comparison of active tcas slant range measurements with ... · tcas on all commercial aircraft with...

Report No. DOT/FAA/RD-95/5

Project Report

ATC-294

Comparison of Active TCAS Slant RangeMeasurements with Interpolated Passive

Position Reports for Use in HybridSurveillance Applications:

Measurements from the June 1999Los Angeles Basin Flight Tests

Lincoln LaboratoryMASSACHUSETTS INSTITUTE OF TECHNOLOGY

LEXINGTON, MASSACHUSETTS

17 October 2000

S.D. Thompson

Prepared for the Federal Aviation Administration.

Document is available to the public throughthe National Technical Information Service,

Springfi eld, Virginia 22161.

This document is disseminated under the sponsorship of the Department of Trans-portation in the interest of information exchange. The United States Government assumes no liability for its contents or use thereof.

TECHNICALREPORTSTANDARDTITLEPAGE

1. Report No.

ATC-294

2. Government Accession No. 3. Recipients Catalog No.

4. Title and Subtitle I I

1 5. Reoort Date Comparison of Active TCAS Slant Range Measurements with Interpolated Passive

Position Reports for Use in Hybrid Surveillance Applications: Measurements from

the June 1999 Los Angeles Basin Flight Tests

17 October 2000

6. Performing Organization Code

7. Author(s) Dr. Steven D. Thompson

8. Performing Organization Report No.

ATC-289

9. Performing Organization Name and Address

MIT Lincoln Laboratory

244 Wood Street Lexington, MA 02420-9108

2. Sponsoring Agency Name and Address Department of Transportation Federal Aviation Administration Systems Research and Development Service Washington, DC 20591

IO. Work Unit No. (TRAIS)

11. Contract or Grant No.

F19628-00-C-0002

13. Type of Report and Period Covered

ATC/August 2000

14. Sponsoring Agency Code

5. Supplementary Notes

This report is based on studies performed at Lincoln Laboratory, a center for research operated by Massachusetts Institute of Technology, under Air Force Contract F19628-95-C-0002.

6. Abstract

Traffic Alert and Collision Avoidance System (TCAS) hybrid surveillance is a technique that makes use of both active surveillance data from the interrogation reply sequence and passive psoition estimates received from Mode S extended squitters. This technique allows TCAS to use passive surveillance once the data have been validated by comparison with active data. The maximum allowable range difference for validation specified by the International Civil Aviation Organization (ICAO) is 200 meters. Data from twenty encounters recorded during flight tests conducted in the Los Angeles Basin in June 1999 were analyzed. The results show that the ICAO specified limits were never exceeded and serve to validate the 200 meter limit.

17. Key Words 18. Distribution Statement

This document is available to the public through the

National Technical Information Service,

Springiield, VA 22161.

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price

Unclassified Unclassified 118

FORM DOT F 1700.7 (8-72) Reproduction of completed page authorized

EXECUTIVE SUMMARY

The Traffic Alert and Collision Avoidance System (TCAS) is a safety system designed to display other aircraft traffic to pilots and to provide alerts and coordinated resolutions necessary to avoid conflicts. TCAS works by actively interrogating other nearby transponder-equipped aircraft, measuring the range and bearing of those aircraft, and tracking them. The FAA has required TCAS on all commercial aircraft with more than thirty passenger seats in U.S. airspace. In addition, the International Civil Aviation Organization (ICAO) has recently issued a world-wide mandate for an Airborne Collision Avoidance System (ACAS), the international version of TCAS.

As the density of TCAS-equipped aircraft increases, it is desirable to explore techniques for reducing the TCAS interrogation rate. One such technique is hybrid surveillance, which makes use of both active surveillance data (position measurements obtained from the standard TCAS interrogation/reply sequence) and passive surveillance data (position estimates from received Mode S extended squitters). The technique allows TCAS to use passive surveillance information from a target once the passive data have been “validated” by comparison with active data. The validation technique is important since it allows TCAS to retain its role as an independent safety system.

The maximum allowable range difference for validation specified by the ICAO ACAS SARPs (International Civil Aviation Organization, Airborne Collision Avoidance System, Standards and Recommended Practices) is 200 meters. However, measurements were needed to fully validate these requirements.

MIT Lincoln Laboratory participated in flight tests conducted by the Federal Aviation Administration (FAA) in June 1999 in the Los Angeles Basin to measure the interference environment and test the performance of the Mode S extended squitter. There were periods during the testing when data useful to hybrid surveillance analysis were recorded. A total of twenty encounters involving four different aircraft were analyzed.

During each encounter, TCAS active range measurements were recorded. “Own” aircraft positions were estimated through linear interpolation of GPS position reports to match the time of the active range measurement. The “target” aircraft positions as reported in the Mode S extended squitter were also interpolated. The positions were converted to 3-D Cartesian coordinates and a passive interpolated range was computed. The difference or delta range was defmed as the active range minus the interpolated passive range. The delta ranges were plotted versus system time and versus range between aircraft for every encounter. Summary histograms of the delta ranges for all encounters were derived.

The validation of the SARPs limit for active/passive range comparison was the primary goal of the work described in this report. A secondary goal was the examination of the active/passive range differences for use in future activities that require the fusion of various sources of surveillance data. Results demonstrate that the range difference specified by the ICAO ACAS SARPS as the maximum allowable difference for validation of reported position was never exceeded and serves to validate the 200 meter range difference limit.

. . . 111

ACKNOWLEDGMENTS

Ann Drumm provided valuable expertise on the principles of operation of TCAS and hybrid surveillance and in reviewing this report.

L-3 Communications Corporation provided the TCAS-2000 units and Mode S transponders designed to transmit extended squitters. These units were formerly owned by Honeywell, Incorporated and generated all of the data analyzed in this report. Note that these were experimental units, developed before the existence of final detailed requirements for either extended squitter or hybrid surveillance. This was the only such equipment in existence at that time, and the fact that L-3 was willing to make these units available ,to Lincoln Laboratory made possible the analysis described in this report. In addition, L-3 Communications supplied software for data extraction from the TCAS-2000 units. L-3 Communications engineers, in particular Stacey Rowlan and Laurie Wyatt, provided valuable assistance in the interpretation of these data.

Ed Glowacki of the FAA’s William J. Hughes Technical Center pre-processed the TCAS data tapes and provided them to MIT Lincoln Laboratory.

Kenneth Saunders and Barbara Chludzinsti wrote the programs for reducing the recorded TCAS surveillance data. These programs extract the active surveillance data and long and short squitter data received from other aircraft.

V

TABLE OF CONTENTS

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V

List of Illustrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..*................................. ix

1.

2.

3.

4.

5.

Introduction ......................................................................................................................... 1

Los Angeles Basin Flight Tests.. ......................................................................................... .3

2.1 Flight Test Overview ................................................................................................... 3

2.2 Hybrid Surveillance Measurements ............................................................................. 4

Sources of Errors in Measurements ...................................................................................... 7

3.1 Active Measurements .................................................................................................. 7

3.2 Passive Measurements.. .............................................................................................. .7

Method of Analysis of Encounters ..................................................................................... 11

4.1 Encounter Analysis ................................................................................................... 11

4.2 Recorded Data ........................................................................................................... 12

4.3 Data Reduction .......................................................................................................... 13

4.4 Interpretation of Results ............................................................................................ 13

Summary of Results .......................................................................................................... 15

5.1 Goals and Methodology.. ........................................................................................... 15

5.2 Validation of SARPs Requirements ........................................................................... 15

5.3 Additional Results and Observations ......................................................................... 18

5.3.1 Additional Data Summaries ............................................................................... 18

5.3.2 Overtake Encounter ........................................................................................... 18

5.3.3 Effect of One Second Update ............................................................................. 19

6. Conclusions ....................................................................................................................... 21

Appendix - Data on Individual Encounters.. ............................................................................ .23

References .............................................................................................................................. 109

vii

LIST OF ILLUSTRATIONS

Figure 1.

Figure 2.

Figure 3.

Figure 4.

Figure 5.

Figure 6.

Figure 7.

Figure 8.

Figure 9.

Aircraft and equipment participating in the Los Angeles Basin Flight Test. . . . . . .._....... 3

Effect of extrapolation on Mode S extended squitter position report. . . . . . . . . . . . . . . . . . . . . . . . . . 5

Illustration of Range Bias Introduced by the Delay in Recording of Target Aircraft Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Position of N40 and N49 During Overtake June 14, 1999, Western Arkansas. . . . . . . . . . 11

Active Interrogations of N49 by N40 on June 14,1999 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Active - Interpolated Passive Ranges for the N40 overtake of N49 June 14, 1999. . . . 14

Summary of Active - Passive Range Measurements for all Encounters with Extrapolated Updates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Summary of Active - Passive Range Measurements for all Encounters without Extrapolated Updates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

N189H target aircraft overtake of N49 on June 17,1999 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

LIST OF TABLES

Table 1. Summary of Encounters with Mean and Standard Deviations of Delta Range Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..a................ 16

ix

1. INTRODUCTION

The Traffic Alert and Collision Avoidance System (TCAS) is a safety system designed to display other aircraft traffic to pilots and to provide alerts and coordinated resolutions necessary to avoid conflicts. TCAS works by actively interrogating other nearby transponder-equipped aircraft, measuring the range and bearing of those aircraft, and tracking them. The FAA has required TCAS on all commercial aircraft with more than thirty passenger seats in U.S. airspace. In addition, the International Civil Aviation Organization (ICAO) has recently issued a worldwide mandate for an Airborne Collision Avoidance System (ACAS), the international version of TCAS.

As the density of TCAS-equipped aircraft increases, it is desirable to explore techniques for reducing the TCAS interrogation rate. One such technique is hybrid surveillance, which makes use of both active surveillance data (position measurements obtained from the standard TCAS interrogation/reply sequence) and passive surveillance data (position estimates from received Mode S extended squitters). The technique allows TCAS to use passive surveillance information from a target once the passive data have been “validated” by comparison with active data. The validation technique is important since it allows TCAS to retain its role as an independent safety system. TCAS can then use the passive data until the target becomes a near-threat, at which time TCAS reverts to active surveillance of that target. The use of passive data is expected to result in a significant decrease in the TCAS interrogation rate, thus allowing TCAS to delay or avoid the range reduction that is now required in high density traffic airspace.

The maximum allowable range difference for validation specified by the ICAO ACAS SARI% [ 11 (International Civil Aviation Organization, Airborne Collision Avoidance System, Standards and Recommended Practices) is 200 meters. However, measurements were needed to fully validate these requirements.

MIT Lincoln Laboratory participated in flight tests conducted by the Federal Aviation Administration (FAA) in June 1999 in the Los Angeles Basin to measure the interference environment and test the performance of the Mode S extended squitter. There were periods during the testing when data useful to hybrid surveillance analysis were recorded. A total of twenty encounters involving four different aircraft were analyzed.

During each encounter, TCAS active range measurements were recorded. “Own” aircraft positions were estimated through linear interpolation of GPS position reports to match the time of the active range measurement. The “target” aircraft positions as reported in the Mode S extended squitter were also interpolated. The positions were converted to 3-D Cartesian coordinates and a passive interpolated range was computed. The difference or delta range was defined as the active range minus the interpolated passive range. The delta ranges were plotted versus system time and versus range between aircraft for every encounter. Summary histograms of the delta ranges for all encounters were derived.

Chapter 2 of this report describes the Los Angeles flight tests. Chapter 3 discusses the sources of errors in active and passive range measurements. Chapter 4 describes the method of analysis of each encounter, Chapter 5 presents a summary of the results, and Chapter 6 presents the conclusions.

1

The validation of the SARPs limit for active/passive range comparison was the primary goal of the work described in this report. A secondary goal was the examination of the active/passive range differences for use in future activities that require the fusion of various sources of surveillance data.

2

2. LOS ANGELES BASIN FLIGHT TESTS

2.1 Flight Test Overview

The Federal Aviation Administration (FAA) conducted flight tests in the Los Angeles Basin to measure the interference environment and test the performance of 1090 MHz Extended Squitter [2,3]. The flight tests were conducted on four days (June 16-19, 1999) and involved an instrumented Boeing 727 (N40) and Convair 580 (N49) supplied by the FAA’s W. J. Hughes Technical Center (WJHTC). Two other aircraft, a United Parcel Service Boeing 727 (N904UP) and a Honeywell Citation (N189H), participated during portions of the four days of testing. In addition, N40 and N49 took data on June 14, 1999, during their flight to Los Angeles. There was also a ground station that recorded data, but these data were not pertinent to this analysis. A summary of the aircraft that participated in the tests and their equipment is presented in Figure 1.

Honeywell Citation

GPS Mode S transponder TCAS-2000

UPS 8727

FAA B-727

GPS LDPU Mode S transponder TCAS-2000 Additional Data Recording

GPS LDPU Mode S transponder

GPS LDPU Mode S transponder TCAS-2000

Figure 1. Aircraft and equipmeetparticipating in the Los Angeles Basin Flight Test.

The significance of the equipment is as follows. All aircraft were equipped with Global Positioning System (GPS) units that provided updated position reports once per second. All aircraft were also equipped with L-3 Communications supplied Mode S transponders capable of transmitting extended squitters on 1090 MHz. Extended squitters containing GPS position reports were transmitted approximately twice per second. Three of the aircraft were also equipped with TCAS-2000 units supplied by L-3 Communications. These units actively interrogated target aircraft and record the target measured range and bearing and reported altitude. These units also recorded own GPS position reports and GPS position reports contained in Mode S extended squitters received from other aircraft. The TCAS-2000 units were the source of the raw data for this analysis.

In addition, three of the aircraft were equipped with Link and Display Processing Units (LDPU) provided by UPS Aviation Technologies. The LDPU contains a 1090 MHz receiver and a Mode S reply processor and was used to supply processed data to several devices used in the measurement program. The LDPU was significant to this analysis in one important aspect. The LDPU receives once per second position reports from the GPS and extrapolates those reports to provide estimated position reports five times per second to the Mode S transponder. The Mode S transponder which transmits extended squitters twice per second will transmit the last updated or extrapolated position report. Because the N189H configuration did not extrapolate position, the Mode S transponder on that aircraft reported the last position supplied by the GPS. The significance of this is illustrated in Figure 2. The position report contained in the second squitter could be up to one second old. The 1090 MHz Minimum Operational Performance Standards [4] (MOPS) requires the faster update rate, so production extended squitter equipment can be expected to perform the extrapolation. For the flight testing, N189H was equipped with an experimental configuration.

The LDPU data were also used in generating the aircraft tracks plots shown in this report and used to illustrate relative aircraft positions. However, only data recorded on the TCAS-2000 units were used to compare active interrogation slant range measurements with computed ranges based on extended squitter position reports.

2.2 Hybrid Surveillance Measurements

The main purpose of these flight tests was to measure the interference environment and performance of the 1090 MHz extended squitter, not to provide data for hybrid surveillance analysis. However, there were periods during the testing when data useful to hybrid surveillance analysis were recorded. Periods of interest occurred whenever any of the three TCAS-equipped aircraft was within active surveillance range (approximately 20-30 nm) of another test aircraft. During this time, the TCAS 2000 unit recorded three key types of information: the TCAS active slant range measurements, its own aircraft position reports, and the Mode S extended squitter position reports received from the test aircraft. Position reports were based on GPS units on the respective aircraft. For this report, only TCAS data recorded on N40 and N49 were analyzed. From these two aircraft, there were twenty different “encounters” that were suitable for hybrid surveillance analysis. Two of these encounters are subdivided into two parts because of a TCAS data recording reset that created a gap in the recorded data. These encounters last from less than a minute to over twenty minutes. For this report, “own” aircraft are N40 or N49 and target aircraft are N40, N49, N904UP, and N189H.

4

Position Reported

with extrapolation: est. position at 0.650 set

w/o extrapolation: GPS position at 0 set I

w/o extrapolation: GPS position

0 Aircraft position recorded by GPS (once per second)

O LDPU extrapolated position estimates

--L--n Aircraft position when Mode S extended squitter position report is sent (twice per second)

Figure 2. EfSect of extrapolation on Mode S extended squitter position report.

5

3. SOURCES OF ERRORS IN MEASUREMENTS

3.1 Active Measurements

The active slant range is computed by measuring the elapsed time between an active TCAS interrogation from “own” ship and the receipt of a corresponding reply from the Mode S transponder on the “target” aircraft. The computation assumes a 128 psec transponder turnaround time on the target aircraft. According to the Minimum Operational Performance Standards (MOPS) for Mode S transponders [5], this 128 psec turnaround time has a tolerance of ho.25 psec with a jitter of kO.08 psec. This would result in a particular transponder introducing a bias error that remained essentially constant of approximately k37.4 meters with a measurement to measurement jitter of approximately ~k12.0 meters. All of the transponders used in these tests were L-3 Communications Corporation XS950 Mode S transponders. It is unknown whether or not a particular manufacturer might have a similar bias in like manufactured units. The characteristics of production ADS-B capable transponders manufactured by L-3 and other manufacturers are yet to be determined.

3.2 Passive Measurements

The passive range measurements were computed by interpolating own and target aircraft position reports (latitude, longitude, and altitude) to correspond with the TCAS system time of active range measurement. These position reports were used to compute slant range by first using algorithms to convert the positions to a 3D Cartesian coordinate system [6] and then computing the range directly. The ranges were also independently computed using algorithms developed for surveillance systems range computations [7]. Agreement was within approximately 0.5 meters.

There are at least three sources of error in the passive range computations. First are errors in the aircraft reported positions due to uncertainties in the GPS reports. The Standard Positioning Service (SPS), at the time of the flight tests, provided predictable accuracies of 100 meters 2 drms, 95% in the horizontal plane [8]. Errors in GPS position are due to intentional dither of the CIA code (which has since been discontinued), errors in estimating ionospheric delay propagation, and Geometric Dilution of Precision (GDOP) due to satellite geometry. The nature of the error sources implies that there should be some correlation in position error to aircraft in the same vicinity. That in turn should result in less error in range computation than if the errors were uncorrelated.

A second source of error results from the interpolation of position reports to correspond with the times of the active interrogation. Care was taken to verify that there were no large gaps in own or target position reports. TCAS interrogations are transmitted once every five seconds until the target aircraft is perceived to be a potential threat. Then, the interrogation rate is increased to once per second. Own and target aircraft GPS positions recorded on the TCAS-2000 were interpolated to match these times. Based on the GPS position update rates and very low accelerations observed during these encounters, errors due to interpolation are considered negligible.

Third, there will be an error in range calculations due to the time required for the target aircraft to read its GPS position, store that in the transponder, send the position report via Mode S

7

extended squitter, and have the receiver aircraft decode and time-stamp the target aircraft position. This results in an error that is dependent on the time delay and the velocity vector of the target aircraft relative to own ship. The effect is that the target ah-craft seems to be reporting the position it was at some A time past. Figure 3 illustrates this effect for a crossing target aircraft. Initially, the computed range is larger than the actual range, but after the target aircraft passes, the computed range is shorter than the actual range. Similarly, in a head-on crossing, the target aircraft computed range is longer than the actual range before the crossing and shorter after the crossing.

4 True range at time t

t.- ..__. __ Computed range based on delayed position report

Computed range shorter Computed range longer than true range than true range

Figure 3. Illustration of Range Bias Introduced by the Delay in Recording of Target Aircraft Position.

Note that the magnitude of the difference is a function of the ground speed of the target aircraft and relative angles of the velocity vectors of the two aircraft. Thus, the errors will be larger for a head on crossing than for a right angle crossing illustrated above. The effect is to cause a bimodal distribution in the measurements of the range differences with the two peaks corresponding to measurements before and after the crossings.

8

The GPS navigation avionics updates the position report once per second. Aircraft equipped with LDPUs transmit GPS position reports that are extrapolated ahead of the last GPS report to estimate the position at 250, 450, 650, and 850 millisecond intervals. The extrapolation will significantly reduce the bimodal characteristic of the measurements as compared with other experimental equipment not yet providing extrapolated data. In the Los Angeles tests, all aircraft except N189H were equipped with LDPUs.

4. METHOD OF ANALYSIS OF ENCOUNTERS

4.1 Encounter Analysis

A total of twenty encounters were analyzed. Each encounter was analyzed using the same procedure that will be described here for one encounter. The results of each analysis are given in the Appendix and summarized in Table 1 in Section 5. The encounter used here as an example is encounter 1. Own aircraft was N40 and the target aircraft was N49. The encounter involved N40 overtaking N49 on June 14, 1999 after both aircraft departed Fort Smith, Arkansas. The tracks of the aircraft are shown in Figure 4.

06/14/1999 20:10:31 -20:32:04

I 20:20 20:25 20~30

time GMT

Figure 4. Position of N40 and N49 During Overtake June 14, 1999, Western Arkansas.

11

The position data are the GPS reported own position data available from each aircraft’s LDPU. An “0” marks the position at the start of the data recording time period and an “x” denotes the position at the end of the time period. Data recording interrupts will be noted on some encounters. For all encounters except 1 & 2, which took place in western Arkansas, the positions are referenced to the ground station just west of the Los Angeles International Airport. In Figure 4, the positions are referenced to the departure point. The times referenced in the title of Figure 4 and all other plots are automatically generated from the data to ensure accuracy. On June 18, all times recorded aboard N40 were exactly two hours different from the actual time. This is because, on this day only, the TCAS recorded personal computer (PC) time was inadvertently miss-set by two hours. This is reflected in the plots in the Appendix for encounters 11 through 15 where the position times differ from the data analysis times by two hours. The PC times are included in the data as an aid in comparing the data with other data sources and are approximate although believed to be within &l second. These times are not used in comparing active slant range with passive interpolated range; for that comparison only TCAS system time is used. TCAS system time is the time, in seconds, since system power-up.

4.2 Recorded Data

Data of interest are recorded during periods when both active and passive range measurements are available. The data file analyzed in this case contains active range measurements made by N40 on N49 during the overtake and extended squitters received from N49. Figure 5 is a plot of the A time gaps between active interrogations

N40 active interrogations of N49 June 14,1999

20:15 2o:zo 2025 ?.0:30 time (GMT)

-30

* - 25

4 %

-20 p

5 ru.

$15 g 57 E R ”

-10 3. g

-5

-0

Figure 5. Active Interrogations of N49 by N40 on June 14, 1999.

12

and range between aircraft, both as a function of time. We see active interrogation every five seconds until the target aircraft (N49) is considered a possible threat. At that point, average active interrogation rate increases to once a second.

The next step is to check for time gaps in the received squitter position reports. The concern is that the interpolation of target aircraft position will be compromised during coasting periods.

4.3 Data Reduction

Each TCAS active range measurement is recorded along with the TCAS system time at which the range measurement was made. A linear interpolation is then performed on the GPS reported “own” position reports to estimate the position (latitude, longitude, and altitude) of own aircraft at the time of the active range measurement. Another interpolation is performed on the “target” aircraft positions as reported in the Mode S extended squitter. The positions are converted to 3-D Cartesian coordinates and a passive interpolated range is computed. The difference or delta range is defined as the active range minus the interpolated passive range. Because of the time delay in reporting target aircraft position, there is an expected bias based on the geometry of the relative velocity vectors as described above. The delta range is plotted versus system time and versus range between aircraft. This is illustrated in the first two sub-plots in Figure 6. The third subplot is a histogram of delta range measurements over the time period of the event. The mean and standard deviation are computed and printed on the plot. Because the distributions are not Gaussian, care should be taken not to attribute Gaussian confidence intervals to the standard deviations.

4.4 Interpretation of Results

The delta range histogram exhibits a bimodal characteristic due to the time delay bias of the target aircraft as described in Section 2.2 and illustrated in Figure 3. This is most easily seen in the plot of delta range versus system time during the overtake. The active minus the passive range is approximately 111 meters before the overtake and 57 meters after the overtake. This effect was consistent in all of the observed events. Note that there are more measurements before the crossing than after the aircraft pass. This can be seen by the distribution of the density of data points in the fast two subplots. It is due to the increase in active interrogations before the crossing. The mean of the delta range measurements for this encounter was slightly positive (87 meters).

Notice that there is no apparent change in delta range as a function of range or time before or after the overtake, only as the overtake occurs and there is a change in the geometry of the relative velocity vectors of the aircraft. This is consistent with observations in the other encounters.

This procedure was carried out for every encounter. In cases where the data recording was interrupted during an encounter, the analysis was broken into two parts.

13

-50 -

Active - Interpolated Passive Ranges 14-Jun-I 999 20:10:31 -20:32:04

own aircraft :n40, target aircraft :n49

.

I I , I I I

1000 1200 1400 System time (set)

1600 1800 2000

. . - l . . . . .

. ..***

l .* . : . l *

l . . . l

l . .. l

l . . . l l

.

i

-50’ 0 5

_I

10 15 20 25 30 Active Range (nm.)

mean 87.449 40 - std dev 36.07

-300 -200 -100 0 100 200 300 Delta Range (m)

Figure 6. Active - Interpolated Passive Ranges for the N40 overtake of N49 June 14,1999.

14

5. SUMMARY OF RENJLTS

5.1 Goals and Methodology

The primary goal of this effort was validation of the SARPs limits for active/passive range comparison. The SARPs recommendation is that passive and active range data agree within 200 meters in order for the passive data to be considered valid. For purposes of this report, the 200 meter limit was considered to be valid if the delta range measurements corresponding to production equipment were within 200 meters. A summary of the delta range measurements is given in Section 5.2 and Table 1. As shown in Figure 7, for encounters with extrapolated updates, i.e., equivalent to production equipment, all delta range measurements were within 200 meters.

The secondary goal was examination of active/passive range differences for use in future activities that require the fusion of various sources of surveillance data. Additional discussions of the data related to this goal are contained in Section 5.3

There were twenty encounters analyzed using the methods described in Section 4. The data were recorded on N40 or N49 and the target aircraft were N40, N49, N904UP, and N189H. Table 1 summarizes the encounters analyzed. p refers to the mean of all measured values of active range minus the interpolated passive range during the encounter. CY refers to the standard deviation. Encounters with N189H as the target aircraft are shaded to indicate there were no extrapolated updates of GPS position data. Plots of the positions of the aircraft and the delta range measurements for each individual encounter are listed in the Appendix.

5.2 Validation of SARPs Requirements

One approach at summarizing the data is to simply combine all delta range measurements (active minus interpolated passive range) made for all twenty encounters. However, one aircraft, N189H, did not provide extrapolated updates (five times per second) of the GPS position reports to the transponder. Therefore, data from this aircraft are fundamentally different than data from the other three aircraft. For that reason, the data on encounters from this aircraft are separated from the data of the other aircraft. Figures 7 and 8 are histograms showing all delta ranges measurements for all encounters listed in Table 1. Figure 7 is for aircraft with extrapolated updates and represents thirteen encounters. Figure 8 is a compilation of all encounters with data received from N189H and represents seven encounters. For the encounters represented in Figure 7, all delta range measurements are within 200 meters.

The first observation from the data shown in Figure 7 is that the agreement between the TCAS slant range measurements and the computed passive range measurements is quite good and that the data have very small tails with no spurious outliers. The reason for the overall bias is not known. Since the bias is small, it may simply be due to the small sample of four transponders that were observed, all from the same manufacturer. Regardless, the agreement is remarkably good. Examination of the individual encounters in the Appendix shows no indication that the range differences are a function of range.

15

Table 1. Summary of Encounters with Mean and Standard Deviations of Delta Range Measurements

(Shading indicates aircraft with no position extrapolation)

1 N40 N49 N40 overtakes N49 during climbout

2 N49 N40 It

3 N40 N904UP N40 reverses course to fly 45 degrees to UPS904

4 N49 N40 N49 following N40, 20 miles in trail

5 N49 N40 N49 flies inbound to coast while N40 orbits LAX

6 N49 N904UP N49 flies inbound to coast, UPS flies north un coast

7 N40 N49 maneuvering to landings

s. ~.-~ N49 :.~ ‘N189H ~... head-on crossing I~: I. .-.I : -_, r -I? . .

10 N49 N40 maneuvering to landings 11 N40 N189H far anart crossing 12 1, ;. N40 ,-.’ 1 N189H.. 1 head on, data stopped before

13 14

crossing . I - N40. -N189H‘ headon after crossing - --~ -Y N40 ’ NW@ head on &ossing slight&n by ..- _? -i-z

-il” -C .. both aircraft (same track)

N40 N189~ diverging at right angles, far anart 16 N49 N40

17 N40 N49

N40 overtakes N49 during departure N49 departing, N40 departing behind at right angles

18 N40 N49 N49 crosses at right angles in front of N40

19 N49 N40

20 N49 N40

N49 departing, N40 departing behind at right angles. Same as 17 right angles departing continuation of right angles departing ending with “U” turn by N49

6114 lo:55 prior 19 lo:38 after

I! 11:45 prior 11’ 27 15:25 after 85 35

6/16 0:3Oprior 32 23 3:26 after turn 93 14

6/16 I

1:52 74 21 I I

6117 1 5:47 79 1 21 6/17 I 0: 15 prior -88 44

3% after’. I I I78 43 6/17~ 8:14overtake -66 42

.~ ~4:OOturn 80 105 4:29.opposite 207 54

6117 8~28 43 22 6/18 3:09 84 43 6/18 3:15 -50 33

6/18, 2:07 218 49 6/18 I:39 prior -66 46

I:27 after 209 39 6/18 2:28 114 43 6/18 7:04 10 32

6119 3:oo 120 17

6119 3:35 35 27

6119 0:16 21 15 4:50 57 17

16

Active _ Interpolated Passive Range Measurements N4O.N49,N904UP

Los Angeles June 1999 I I I I 8 160

I 160-

14Q-

IM-

IOO- mean 63.902

std dev 42’14

60-

60-

40-

x)-

01 ail -200 -100 3c IO

Delta Range(m)

Figure 7. Summary of Active - Passive Range Measurements for all Encounters with Extrapolated Updates.

Active-Interpolated Passhre Range MBasuremenls N169H

Los Angeles June 1999 , I I I I 45

I 40 -

35 -

30-

25-

20 -

15-

IO-

5-

o- -300

I q -200

Delta Range (m)

Figure 8. Summary of Active - Passive Range Measurements for all Encounters without Extrapolated Updates.

17

The effect of updating the GPS position five times per second is evident in comparing Figures 7 and 8. The bimodal characteristic of the data due to the time lag effect is much more pronounced in the data without the higher update rate. It is important to note that the 1090 MHz MOPS3 require the higher update rate. The LDPU acted as an emulation of the expected performance of all production equipment. A slight bimodal characteristic can be noted in Figure 7 and is easier to detect in certain individual encounters listed in the Appendix. Discussion with UPS Aviation Technologies revealed that subsequent to the Los Angeles tests, the LDPU software- was updated to change the extrapolated position times from 250,450, 650, and 850 milliseconds to 300, 500, 700, and 900 milliseconds to better estimate the time bias. The effect of this should be to tighten the distribution illustrated in Figure 7 even more.

The data collection rate depended on the relative geometry of the aircraft. In some cases, active interrogations increased and thus so did the delta range measurements. However, the geometry also determined the time bias of the passive range measurements as described in Section 3.2. The encounters were chosen based on the availability of active range measurements and may not reflect the delta range measurements that might be encountered in normal flight. It is important to note that the data were limited to two recording aircraft and four target aircraft, and that all target aircraft were equipped with an L-3 Communications Mode S transponder.

5.3 Additional Results and Observations

5.3.1 Additional Data Summaries

Another way to summarize the data is to take the mean of the means listed in Table 1. This process weights each encounter (or part of an encounter) equally regardless of the number of data points. The mean of the eighteen individual means listed in Table 1 for target aircraft performing position extrapolation is 60.6 meters, not significantly different than the mean of all of the individual measurements shown in Figure 7,63.9 meters.

Since there were only two recording aircraft, N40 and N49, we can separate the eighteen individual means for target aircraft performing position extrapolation into two components representing the two recording aircraft. There are seven individual means listed in Table 1 in which N40 was the recording aircraft and the target aircraft was performing position extrapolation. The mean of means for N40 is 85.4 meters, There are eleven individual means in Table 1 in which N49 was the recording aircraft and the target aircraft was performing position extrapolation. The mean of means for N49 is 44.8 meters. Because of the limited number of cases, it is not clear whether or not this difference is statistically significant.

Similarly, the individual means listed in Table 1 can be broken up by target aircraft. There are 10 means in which N40 was the target with a mean of means of 42.5 meters. There are 5 means in which N49 was the target with a mean of means of 95 meters. There are 11 means in which N189H was the target with a mean of means of 74.5 meters and there are 3 means in which N904UP was the target with a mean of means of 64 meters.

5.3.2 Overtake Encounter

There are several individual encounters that offer additional insights into the results. Encounters 1 and 2 are the same encounter recorded by two different aircraft. The encounter is a slow over-take of N49 by N40 during climb-out. In one case, N40 is the own aircraft and N49 is

18

the target aircraft and in the other case N49 is the own aircraft and N40 the target aircraft. The data are unique in this analysis in that it offers over twenty minutes of uninterrupted data recording of the same event as recorded by two aircraft. Table 1 shows that the mean of the delta ranges changes from 111 meters before the over-take to 57 meters after the over-take as recorded on N40. The mean of the delta ranges recorded aboard N49 changes from 11 meters to 85 meters. These changes are consistent with the bias introduced by the time delay of the target ship reporting its position as described earlier except that there exists an overall bias consistent with that observed in the summary data presented in Figure 7. That is, if there were no overall bias one would expect that N40 would measure positive delta ranges before the over-take and negative delta ranges after the over-take. The delta ranges measurements do make a shift down in magnitude with the over-take but remain positive. The data as averaged in Table 1 include the actual over-take event itself. If we examine the data in the Appendix for these encounters and take out the moments of over-take, it is estimated that the mean shifts from 110 meters to 40 meters for N40 own ship and N49 target ship measurements. For N49 own ship and N40 target ship measurements the means change Corn approximately 0 meters to 110 meters. This is a 70 meter change for N40 measuring N49 and a 110 meter change for N49 measuring N40. These results are consistent with the fact that N40 had a higher ground speed than N49. If we look at encounter 16, another overtake of N40 by N49 we see that N49 recorded a mean of 10 meters with N40 as the target in trail. This is consistent with the 11 meters listed in Table 1 for encounter 2 prior to the over-take. The increase by 50 milliseconds in the extrapolation times mentioned above should reduce this time bias.

5.3.3 Effect of One Second Update

It is interesting and instructive to examine individual encounters involving N189H, which did not have the extrapolated GPS position updates, as the target aircraft. As explained above and illustrated in Figure 2, the GPS position in this case is updated only once per second. Encounters 8, 12, 13, and 14 are all head on crossings with N189H as the target aircraft. Encounter 8 is recorded aboard N49. The mean of delta ranges before the crossing is -88 meters and the mean after the crossing is 178 meters. The shift is consistent with a delay in the target aircraft reported position. Again, we see an overall positive bias. The change in delta range measurements from before the crossing until after the crossing is 266 meters. Note that this is significantly larger than the changes observed in encounters 1 and 2. Encounters 12 and 13 are a similar head on crossing with N189H but are measured aboard N40. We see a change from -50 meters delta range before the crossing to 218 meters after the crossing, a total change of 268 meters, almost identical to that observed aboard N49 in encounter 8. Encounter 14 is another head on encounter with N189H recorded aboard N40 with consistent repeatable results; -66 meters before the crossing and 209 meters after the crossing, a change of 275 meters.

Finally, encounter 9 records an overtake of N49 by N189H as recorded aboard N49. The data averaged in Table 1 are somewhat misleading in that it averages the mean after the takeover with a turn by N49. If we examine the data during the overtake as illustrated in Figure 9, we see that the change is from approximately -65 meters in delta range to 175 meters in delta range, a total change of 240 meters which is consistent with the results for the head-on crossings. Also, after N49 turns around, the delta range measurement mean is 207 meters which is consistent with the head-on crossing encounters after the crossing. This is encouraging because we would expect

19

Active - interpolated Passive Ranges 17-Jun-1999 21:00:00 -21:04:00

own aircraft :n49, target aircraft :n189h 1 I I I I

-2M) ’ 6250

, 6300

I I 6350 6400

System time (set)

I I 6450 6500

300 I I I I I I .

200 - . .*.***.. . * .

. &..*. **’ * *.“- . l

** .:

l .-. *...* . . . .

E t.‘.\ . :a . . . . * l *** .* *

*..* * lh “5

1

. . r’

. .- .*

2. *

g) ioo- .

.

5 !z

@ Q-

x

&.. : -*

. . * : d-y....% *,,*. . * .

-100 - * *

- . ‘.-. . ’ ,

l . .

-200 ! t r I I I 0 0.5 1 1.5 2 2.5 3 3.5

Active Range (nm.)

25 1 I I

mean 80.369 20

t std dev 105.1

0 Delta Range (m)

Figure 9. Nl89H target aircraft overtake of N49 on June 17,1999.

that a change in delta range measurements created by a time delay in recording the target aircraft position would be the same regardless of whether the event were an overtake or a head-on crossing. This seems to be the case.

An estimate can be made of the actual time delay in the reporting of the position of the target aircraft by examining the change in delta range and estimating the ground speed of the target aircraft, in this case N189H. We assume an average change in delta range of approximately 270 meters during the three head-on crossings. Examining the position plots of N189H in the Appendix for these events, we estimate ground speeds of between approximately 269 kts. and 330 kts. with an average of 294 kts. If we take half of the 270 meter delta range change, or 135 meters, it will take an aircraft traveling 294 kts approximately 0.9 seconds to cover that distance.

20

6. CONCLUSIONS

Data indicate that for aircraft meeting the 1090 MHz MOPS requirement of five per second GPS position update rate, passive computed range measurements consistently agree with TCAS active range measurements within 200 meters.

There is a bias in the mean of the grouped data of approximately + 64 meters; that is, on average the measured active range is 64 meters greater than the interpolated passive range. This bias is greater than can be explained by the transponder turnaround time tolerance specifications oft 0.25 psec (5 37.4 meters). It is important to note that the magnitude of the bias observed in this data set would be irrelevant for TCAS operational effectiveness. Factors that can contribute to this bias include transponder and TCAS antenna cable lengths, transponder turnaround time, and TCAS range calibration. These are factors that may be calibrated out in certified standard installations.

The units aboard N40 and N49 were bench checked to verify that their turnaround times were within tolerance, however the transponder aboard N49 was at the upper limit of the tolerance and the transponder aboard N40 was in the middle of the specifications. This is consistent with the observation’that the bias for N49 as a target was greater than for N40 as a target.

The standard deviation of the delta ranges is approximately 43 meters. The time tag bias described in section 3.2 and illustrated in Figure 1 will account for an unknown portion of this deviation. The data exhibit a sharp cutoff in the tails of the distribution; that is, there are no outliers.

There was no indication that the differences in range measurements were a function of range.

There were no indications of erratic passive range measurements.

The validation of the SARPs limit for active/passive range comparison was the primary goal of the work described in this report. A secondary goal was the examination of the active/passive range differences for use in future activities that require the fusion of various sources of surveillance data. Results demonstrate that the range difference specified by the ICAO ACAS SARPs as the maximum allowable difference for validation of reported position was never exceeded and serves to validate the 200 meter range difference limit. The SARPs represent the first attempt- at specifying range limit differences for airborne surveillance data fusion. This report is the first look at any data to validate the 200 meter limit. No active and passive data have been available until the Los Angeles tests. From this data, we conclude that the 200 meter limit can be supported with production equipment and that we can commit to proceed with hybrid surveillance development based on the current SARPs requirements.

21

APPENDIX - DATA ON INDIVIDUAL ENCOUNTERS

23

Encounters 1 and 2

N40 overtakes N49 during climbout

24

80

60

40

-40

-60

06/l 4/i 999 20:10:31 -20:32:04 . . . . . _

. . . . .

.

. _ . . . . . . . _.

.._ . . . ..-.

-120 -100 -80 -60 -40 nmi. east of reference

-20 0

x104 3- . . . . . . . . . . . ‘ . . . ..‘..‘...““......‘.....“...‘.‘.‘.”..~ _._.__ . . . . . . . . . . ...‘. . . . . .

2.5 _. . . . ..I . . . . . . ..____._. .._ I. ._t_.. . .._...___.~ ._._______

20:20 time GMT

20:25 20:30

25

06/i 4/i 999 2O:i 0:31 -20:21:26 80

60

40

. .._.

. . . ..~

r....L

. . . .

...“.

-40

-60 . . .

. .

.

. .

.

. . .

.

. .

. . .

.

. . . . . . . . . . . . . .._..


0

I 20:15

time GMT

26

.

80

60

40

-40

-60

06/l 4/l 999 20:21:26 -20:32:04 . . . . . . . . ‘ . . . . . . . . . . . . . _ .

. . . . . . . . . . . . . . . . .._.....

. . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . .

._...................................~ ......

..... .._ ....................................

............................................

._............................~..~ ..........

. . _ .

. .._...

. . . . . .

. . . . . . .

I . . . . .

. . ..~........_..... . .

.

.

.

.

- .

... .._......_.......~ -

.......................

.......................

.......................

.......................


-20

x10” 3r __..____._.__._______....__...,._________..... __ . .._..___..__._.. _ . . . .._ __ . ..-.

2.5 _...._.._..... .._ _ .._.._. I ...............I...._

1 20:25

time GMT

I 20:30

27


own aircraft :n40, target aircraft :n49 I I I I I 160

140 l . .

. l .

. .a*.. .

.

. . . 0..

. * : l

. . . .

. .

. . . -0 .

.

.

. .*

: l .

.* . .

. .

. .-

l . . .

. 0.

. .

. .

.

80 .

60’ 1 I I I I I .

600 700 800 900 1000 1100 1200 1300 System time (set)

160

140

E &120 5 fx cd 100 22 6

80

60

. .

. I 1 I I -

0 5 10 15 20 Active Range (nm.)

50

40

30

20

10

mean 110.69

std dev 18.72

Delta Range (m)

28

c

150 I


own aircraft :n40, target aircraft :n49 I I I I I I

-50 1200

I

1300 I I I I I I

1400 1500 1600 1700 1800 1900 2000 System time (set)

Active Range (nm.)

mean 57.399

std dev 30.47

Delta Range (m)

29

150 I


own aircraft :n49, target aircraft :n40 I I I I I 1

poop.’ /

8 * * .*.

2 50- l :* l

.

l : .

. . .

l * . ., . . .

. -0 . :-

a . . :

2

I2 o-

l %r

-.*. l ‘.

.* . *..a ,’ l : u* . . .’ -

. :.,

.

s l *.. ’ .- . ’ . . /

‘. ..-

l ..* l l . . .** l r-3 l .* +

l ’ *. . 0. l

. l .A .hr=.

. . .-- .

‘0% c,

‘. . .

. 0.. z

.

. . . *

-50 I I I 1 I I . I 2100 2200 2300 2400 2500 2600 2700 2800 2900

System time (set)

150 I 1 I 1

.

PO0 . . . .

$I fj 50-

2

d o-

. l

.

. .* . . .

. l .

.

0.. . . l *

** . -0.

.

. . l

.

-50 ’ .! I I I 0 5 10 15 20 25

. .

.

Active Range (nm.)

-200 0 Delta Range (m)

30

200

Active - Interpolated Passive Ranges l4-Jun-I 999 20:21:26 -20:37:51

own aircraft :n49, target aircraft :n40 I I I I I I I 1 I

-50 l I I I I I I I I I

2800 2900 3000 3100 3200 3300 3400 3500 3600 3700 3800 System time (set)

200 I I I I I I I I

150-

E &loo- Ei IT g 50

rz O-

-50 l I I I I I I I I

0 5 IO 15 20 25 30 35 40 45 Active Range (nm.)

30

25

20

15

IO

5

0

I

mean 85.324

std dev 35.03

Delta Range (m)

31

Encounter 3

N40 reverses course to fly 45 degrees to UPS 904

32

06/l 6/l 999 17:58:54 -18:03:18 2c

15

10

5

0

-5

__.,...._....................-.........-.................-.._._ __

-5 0 5 nmi. east of reference

0’ i I

17:59 18:OO I

18:Oi time GMT

I I

18:02 18:03

33

06/l 6/l 999 17:58:54 -17:59:27 20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . : . . . . . . . . . . . . . . . . . . . . . . .

I 0

nmi. east of reference

34

06/l 6/i 999 17:59:52 -18:03:18

\,x 8 \ . . .._...~_..................~...,....

0 nmi. east of reference

35

80 I

Active - interpolated Passive Ranges f6-Jun-1999 175854 -17:59:27

own aircraft :n40, target aircraft :n904u I 1 I I I I

.

60 - . .

E . . l .

g) 40- l . .

5 : *

a

.

.

2 20 .

8 . .

(-j- l :

.

-20 3015

I 3020

I 3025

1 I 3’035

I 3030 3040

System time (set)

I I 3045 3050 3055

60 - ’ .

E l .

. . 8 40-

.: -*.

s . a . g 20

.

l2 . .

. O- . .

.

80 I I I I I I 1

.

-20 1 1 I . , I ! I 7 8 9 10 11 12 13 14 15

Active Range (nm.)

6 I I

5- mean 31.975

std dev 22.55

4-

3-

2-

l-

0 I I

Delta Range (m)

36

Active - Interpolated Passive Ranges 16-Jun-1999 17:59:52 -18:03:18

own aircraft :n40, target aircraft :n904u 140 1 I 1 I

. . . 120 - . .

E . . . . . . &loo- * ! 1 . .

-

2

a

.:*

l ’ l . *. . l . l *

.

. . ‘*

. l .

g 80

. . l

. . .

.

6

2’

. l

.

60 - .

40’ I I I I

3050 3100 3150 3200 3250 3300

.

System time (set)

140 I I I I I I

. . . 120- . .

E . . . . . .

gJoo- . ! . . l * l . l l

1

. l .

53 . .

. .

a 4* .*** l . . .

2 80

8

l j- l

. . .

60 - .

40 I I I 1 I I

4 6 8 10 12 14 16 18

25

20

15

10

5

Active Range (nm.)

mean 93.102

std dev 14.04

-300 -200 -100 0 Delta Range (m)

37

Encounter 4

N49 following N40,20 miles in trail

38

,

.

-30

-35

-40

-60

-65

-70

. . .

. I

I .

. .

.

. __

.

. .~.

_ . .~. .

. . .

06/i 6/l 999 17:26:49 -17:28:41

. .._.

..........

..........

..........

..........

. .

. .

__..___......

__._._____._.

1 . .

. ..__.._..._.

. . . . . . . . . . . . .

30 35 40 45 50 55 nmi. east of reference

60 65 70

tvliramar NAS

x104

2 . . . . ..~.....................‘.....................I................... ..:.......

. . ; . . .*..... l *-* :

. . . *- . . :. . . . . . . ‘ . . .:; ‘.: ;........ I ._... . _.C . ..*.. ,.:~.*...‘.‘.‘.‘: :: . . . . . . . ,, . . .

,.. . . . . .‘. . . . . . . . . . - *** . *.*... *“:

; N40

”

17:27 17:28 17:28 17:29 time GMT

39

120

100

E 80

g ii

60

% 40 L!k 2 20

0

I


own aircraft :n49, target aircraft :n40 I ‘. I 1

. l

. 0’

* :

. .

. . . l *

.

. . . . . l t . ** .

. .

l ’ #.

.

l . : . *

t .

. . .

.

240 260 280 300 320 340 360 System time (set)

100

E 80

i?~ 60- ii a 40- 2! g 20-

O-

. . - . -I

. l * “‘.: **

t . .

. . .

.

-20 ’ I I I I I . 1 I I I 19.4 19.6 19.8 20 20.2 20.4 20.6 20.8 21 21.2 21.4

Active Range (nm.)

20 r

15

mean 74.03

_ std dev 21.02

10

5

-300 -200 -100 0 Delta Range (m)

40

Encounter 5

N49 flies inbound to coast while N40 orbits LAX

41

2c

C

-60

-80 4

I.........

?-- . . . . . . . . . .

. .~_. .

TL

. . . _

.

.

06/l 6/i 999 19:25:00 -19:36:30 . . . . . . . . . . . . . . . . . . . . ..~.........~~..~.._...~.~......L........

I

-40 I I

-20 0 nmi. east of reference

I I

20 40

x10”

,‘. . . . . . . . . . . . . ..,. . . . . :.-.. . . . . .

=

I::25 I I

19:30 19:35 time GMT

42

.

.

I -.

/

I -.

-80 - -60

. . . ,i.. . _. .

c?- ..,...._..

.

. .

06/l 6/l 999 19:27:34 -19:29:06 . . . . . . . . . . . . . ..-..--................. ‘tr

d

-40 -20 0 nmi. east of reference

20 40

.

43

3 . . .

. .

06/l 6/l 999 19:30:00 -19:31:54 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..- _.__.

Y-.....:..>r< - # .:..LAX.........:...........----

. . . , . . .

. . . ..__.... cl

. . . . . .

.

. . . ..~..........~................____.__...... . . . . . . . . . . .

Kl ;

; %

; \;

,.....,..,.._._._._.___......_.___..._.__........... . . . . . .

..~..............~... . . . . . . .._....................~..~....

; *\

-40 -20 0 nmi. east of reference

20 40 *

44

c


own aircraft :n49, target aircraft :n40 120 I I 1 I I I 1 I

loo- : .

80 .

-

60 - . .

40 - . . l

. 20

. l

- .

30440 I 1 I I I I I I

3450 3460 3470 3480 3490 3500 3510 3520 3530 System time (set)

.

120 1 I I I 1 I I

0. IOO- .

E .

80- .

iz $ 60- . (d 2 40:

. .

. 20 -

. .

.

67.5 68 68.5 69 69.5 70 Active Range (nm.)

70.5 71 71.5

3 I I I I I

2.5 - mean 56.168

std dev 32.29

2-

1.5 -

l-

0.5 -

n I 1 -300 -200 -100 0

Delta Range (m)

45

60


own aircraft :n49, target aircraft :n40

. :

1 I 1

.

.

.*

.x : . .

. l

.

. l

-10 I- 3560 3580 3600 3620 3640

System time (set) 3660 3680 3700

60 I I I I 1 I

. . 0. 50- . .

. I .

E 40- l . . l ..* . 1. l . . .

g : 5 30-

. .I* I .

. l . . . .

a,20- . . . .

*

. .

.

$ IO--

o-* l

.

-10 I I I I I I

58 59 60 61 62 63 64 65 Active Range (nm.)

20 I I I I I

mean 32.746

15 _ std dev 13.27

IO-

5-

-3000 I

-200 I I I

-100 0 100 200 300 Delta Range (m)

46

l

. Encounter 6 -

N40 flies inbound to coast UPS fries north up coast

47

06/i 6/i 999 19:27:02 -19:3&l 1

-10

-50

-60

‘2.LAX.L .._.___: _____.. I.... _.......___.........

. . . .._

. . . . . .

. .._._

i.._._

d _.... . . . I . . . . . . 1%

.._______.___

. . ..‘._........... . . . . _._ . . I__ _

. . . . . . . . . . ......

+y 49; ...................

. . . . . . . . . . . . . . . . . .

. . .._.._._.._

-20 -10 0 IO 20 nmi. east of reference

30 40 50 60

x104

. .._..

N49

.............. . .... ..~..-.-~....--~- .........

...............

~._...-......-.....~..~..~...~..~~.~..~~ ...

.;............:..........-~~............:~ ...

2 - . . . . 1. . , . . ; . . . _ _

. . . : . .

El.5 -..... _ . . . . ;.~.--..

2 g l-a

I-...... -.-...i . . . .

0.5 -. “. . . . ;. . . ,

. I

., . . . . . . . . . .

.‘............ J.......... I ~ L............‘.... . . . . . . . . : . . .

”

19:28 19:28 19:29 19:29 19:30 19:30 time GMT

48

120

Active - Interpolated Passive Ranges 16-Jun-1999 19:27:02 -19:3&l 1

own aircraft :n49, target aircraft :n904u I I L I

ioo- .

z

. . - . . .

$j, 80- . l l

5

. . l

. .

rc

. .

l l .0

g 6o l l .

. .

8

. .

.

l ‘. .

40 - . .

l

20 3350

I 3400

I I 3450 3500

System time (set)

I 3550 3600

‘OO- E - ;. .

$j, 80- * l

. s 0 . . . . cc

. .

$ 60- l * ’ .

.

2i l . t

40 - . . . l .

.

120 I I I I I I I

20 43

I

44 I

45 I I I

46 47 48 Active Range (nm.)

I I

49 50 51

8 I I I

mean 68.162

6 _ std dev 18.25

4-

2-

-3000 I

-200

I I

-100 0 100 200 300 Delta Range (m)

49

Encounter 7

N40 and N49 maneuvering to landings

50

.

-40

-45

-50

430.- 40

. . .

. . .

. . . .

. . . .,.. . .._

06/17/1999 21:16:46 -21:22:33

...L.._.....e.-.... . . . . . . . . . . . . . . . . . .._....._.._............. s \ ; ;*;

45 50 55 60 65 nmi.eastof reference

70 75 80

x104

2

I- .! . . . . . . .

1.5 -.:~............ t I N40

:. ............ . .................................... ..-....: .......

........................ ..~.-..-~~~~~.-.-~.~...~.......- .......

c ’ ! ,

1 . . . . . ..!.!..............................-...-,.............................,.....~~

’ 8 o.5+“;*~~??...; . . . . ..__.____ ;.............:~-1.1-I.~.:.r.~.*..,.,.......~ ,‘......,.

--“+, --I.-_ . .

--*----- -.._-- -.-~I--- _.._ n i 1 I I -‘-f-w---...,, I -II..-

" 21:17 21:18 21:19 21:20 21:21 21:22 timeGMT

51

RangebetweenN40andN49on17-Jun-1999

\ :

\. . . . ..“......‘..........~.................................:~..~........~.~.....‘.......~.......,.... ‘\

18 !\ . . . . . . . . . . . . ..-. . . . . . . . . ..‘.............~............ ..L............“\-_......-...-:............

. . . . . . . . ..~....~...~~.....................~..............~~............__.........................

\,

. . . . . . . . . . . ..-.......... . . . . . .:. .

10 . . .

8 ~. . i . . . .

elf I I I I I I

300 21:17:00 21:18:00 21:19:00 21:20:00 21:21:00 21:22:00 21:23:00 time

52

.

Active - Interpolated Passive Ranges 17-Jun-1999 21 :I 6:46 -21:22:33

own aircraft :n40, target aircraft :n49 1 I I .I

20’ I I I I I 1 300 350 400 450 500

System time (set) 550 600 6;O

. . . . .

l l .

. . ‘.*r .

.- . .

.* .

.

. .

l . .

.

. . . . l * . . .

. . . .

.

.

. . .

l .

. . . . .

. .

. .

* . . . . .

.

. .

.

201 I I I f I I I

6 8 10 12 14 16 18 20 22 Active Range (nm.)

mean 79.208

_ std dev 20.85

20

15

10

5

I

-300 -200 -100 0 Delta Range (m)

53

Encounter 8

N49 and N189H head-on crossing

54

.

. r”. . . *.

. . . . n

. . .._._.__

. . . . ..__..

i . . . L _ . . .

. . ..-___.

.__-._...

..__.‘___

. . , .

_._.

. . .

06/17/1999 19:14:25 -19:14:40

0 :

t &

_..___..__......._____._.

F! “... . . . . . . .._..._ \ u . . . . . ..__.___._____

. . . . . . . . . .

-40 -20 nmi. east of reference

0 20

55

-30

-40

-80

-90

-100 - -60

.-.. . . . . . . . . .~ . .

. . Cl5

06/17/1999 19:15:47 -19:19:31 __.__._....._............

0 : . .

. . . . . . . . . . . ..___._.

. . . . .

. _ - .

_____ _.... i __..__. _ . . . . !/ . . . . . 189HLm.

N49:

. .._.. .._._...._

_.._._*.__..

. . . _ _ _ . ” . .

_....._...........

9 . . I .- --r-r- . . . . . ‘ . . ;. . . _ - . . .

. . . . . . . .._...~_...__.‘...__.....

. . . . . . . . . . . .._...___..____...__.

-50 -40 -30 -20 -10 nmi.east of reference

0 10 20

o- i 19:16

I I I 19:17 19:18 19:19

timeGMT

56

0

2 -50

iti 2 -100

a =

$ -150

I

Active - Interpolated Passive Ranges 17”Jun-1999 19:14:25 -19:14:40

own aircraft :n49, target aircraft :n189h I I I I

i . l

. f

r’ ; .

.

. : .

-200 L 9000

I I 1 I I I I

9002 9004 9006 9008 9010 9012 9014 9016 System time (set)

0

-200 I I I I

5 5.5 6 6.5 7 7.5

. i .

. i

. : .

. : :

.

Active Range (nm.)

mean -88.474

std dev 44.22

0 Delta Range (m)

57

300

Active - Interpolated Passive Ranges 17”Jun-1999 19:15:47 -19:19:31

own aircraft :n49, target aircraft :nl89h I I I I

2250 . ;

l

. . .

b

3’ .

. . l

ii 200- :: . . . .

cc . .

. c-a . = . .

$150- l ’

. . .

i . .

100 I l I I I

0 50 100 150 200 250 System time (set)

IO

8

6

s250 . ; I .

. . . a 3’ . . . P

s ; . . . .

CQ 200 - cc f . .

. a . r . . .

&50- l ’

. . . .

i *.

300 I I I I I I I

100 I I . I I I I

5 10 15 20 25 30 35 40 45

r

Active Range (nm.)

mean 178.43

std dev 43.43

Delta Range (m)

58

L

Encounter 9

Nl89H overtakes N49 from behind, then N49 reverses course

l

,

59

06/l 7/l 999 20:51:46 -21:08:29 . a

-10

-20

-30

-70

-80

-90

I-

5

-100 - 60

. . . . _..._

. _ _ _ . . . . .

__.._...._......... . . . . . . . . ..___A..

. . ..__-.. _...........................

. . . . . . . . . . . . . . . . . . . .~_ .

. . . . . . . . . . . . . . . . . . .

. .

.

.

. . . . ..- -.

. . . . . . _. .

. . . . - . - . .

,........... _..... . . . . . r i . . . , .__._,...... . . . . . . . . __.__.........-

70 80 100 110 120 nmi. east of reference

x104

2 -............... f . . . . . . . . . ..__._..____... f . . . . . . . . . . . . . . _ . . . .._._. ;.--.- .,.-- _... N49

N189H: g ’ -5 -7. . . :~.‘.-r-.-rYY-r.:.‘.‘: _ I_‘~-...~.....‘--.~.‘-.~~:-:

_:___. .-.._. .~. _. . . . . . _. . ._ _I. . , . . . _ . . . .._.. _ .;._.._..__......_.._....

0 I I I 20:55 21 :oo 21:05

time GMT

60

0 06/i 7/l 999 20:51:46 -21 :OO:OO

. .

.

.

. . . . . . . . . . . . . . . . . . .

. . . .

_.._

_...

. . . . . . . . . . . .

. . . . . . . . . .._.__._____

-10

-20

-30

._.L

. . . .

. . . . . . . .

. _

. .

. .

.

_._. _*_-_ __ _ .

. . . . . . . . . . . . . . . . ..___.____.__.._.__. .&K,Jf,@, I....,.; .._.__.; _______; -70

p

-80

-100 - 60 70 80 90 100 110 120

nmi. east of reference 130 140 150 160

0.5

t

. . . . . . _. . . . . . . ‘1.. . . . . . . . . . . . . I.. . . . ‘. . . . . . . . . . . . . . . . . . f

0’ I I

20:55 21 :oo time GMT

61

’ 06/i 7/l 999 21 :OO:OO -21:04:00 0

-10

-20

-30

-70

-80

I- I I 1

. .

Miamar N&S ! :

.

. . . . . . .._.... . . . . . . . _

-100 L 60 70 80 90 100 110 120 130 140 150 160

nmi. east of reference

200 - . . . _............

. - .

. .;. . . . . “.. .

. . . . . .

. . - . -.. .* :. - . .

-. . -

-. . . . i .‘“....“....;:.......‘.............:...................I...................’ . . . .

-- -. : . .

. . . . .

. *

73 & ‘G5 100

:oo time GMT

62

0 , 1

-10

-20

-30

.

.

.

. .

. . . . . . . . . . . . . . . . .

-70

-80

-90

-loo_ _ 60 70

06/i 7/l 999 21:04:00 -21:08:29

.._..

. . . . .

. . . . .

. . . . .

. . . . .

. . . . .

. . .._

. . .._

. . .._

. . . .

. . . .

._..

. . . . . . .

. . . . . . . .

. .

.

. . ..... ........................... 3;; i N49 f t

. _ .... gJg#jjj. ...... t ..... ._..____..____

.A............

. . . . . . .

. . . . . . .

. . . . . . .

. . . . . . .


130 140 150 160

160,s. . . ..I..... ~...; . . . . _ . . . . . . . . . . . . . . . _ . . . . . __ .-.: _ _......... _ .--:......-.... ___.,

: . . . _ . . . .

80 -.

._.._._’

. . . . .

.__.,..:

. . I I 21:06 21:07

time GMT

63

45

40

35

30

$ “E 25

3 ‘Z= 3 20

15

IC

5

20:

Range between N49 and N189H onl7-Jun-1999 I I I

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . ..t...L......~.....__.._.___..._.. . . .

._. .

.I. .

_._ .

. . . .

. . . . . . . . . . .

. . . . . .;.

. . , :.

_............,..,.......,

LOO 20:55:00 21 :oo:oo time

21:05:00 21:10:00

64

I

Active - Interpolated Passive Ranges I’-/-Jun-1999 20:51:46 -21:08:29

own aircraft :n49, target aircraft :nl89h I 1 I I

. I I I I I 5800 6000 6200 6400 6600 6800

System time (set)

500 I I I I I I I -

400 -

E 300- - . . . .

. _

.

.* l *

-200 I I I . I I I I

0 5 10 15 20 25 30 35 40 Active Range (nm.)

25

20

15

10

5

0 i

mean 44.81

std dev 122.5

-300 0 100 200 300 Delta Range (m)

65

Active - Interpolated Passive Ranges 17-Jun-1999 20:51:46 -21 :OO:OO

own aircraft :n49, target aircraft :nl89h 50 I I I 1 1

l .

. .

. .-

O-

. .

.* .

. .

E

. .

. .

. . . l . .* 0.

.

g) -50 - . .

.*- l .

. . : . . .

l . . . .

5

l . . . L ’

0s . l . l . . l . 0. . .

IT l .*

. . l .0 .

. 3

..’ l

. t -

ccl -100 -

i: l . .

.

= . . . :

e***e* .*a .

3 . . . .

2 l . . l # .

. . . . . .

-150 - l . .

.

-200 5700

I I I I I

5800 , 5900 6000 6100 6200 6300 System time (set)

mean -66.454

_ std dev 42

20 r 15

10

5

Active Range (nm.)

0 Delta Range (m)

66

.

.

.

300

200

E g) 100 c

Active - Interpolated Passive Ranges I-/-Jun-1999 21 :OO:OO -21:04:00

own aircraft :n49, target aircraft :nl89h I I I I

.

-200 ’ I I I !

6250 6300 6350 6400 6450 6500 System time (set)

300 I I I I I I

I I I I I I -200 - 0 0.5 1 1.5 2 2.5 3 3.5

Active Range (nm.)

25 I I I I I

mean 80.369 20 - std dev 105.1

15-

IO-

5-

-3000 -200 I II -100 0 100 Delta Range (m)

1

67

500 I


own aircraft :n49, target aircraft :nl89h I I I 1

400 -

E &300 - 5

. l .

.

a .* . l .* . .

cd 200 - .

..a*.. l l * l

. . . l 0..

l . . l

. . . .

et . . . l

6 .- . . .

l .

. IOO- .

0 I I I I I I 6450 6500 6550 6600 6650

System time (set) 6700 6750 6800

500 I I I I 1 I I -

400 -

E &300 - 2 . l .

. .

a . . l .

a 200 - l **a . 0.0 .* . . . l .

l **. l . . ’ .

. . . . _

= .

. . . . l

2 . l .

. . . .

. IOO- .

0 0

I I I I I I I

5 10 15 20 25 30 35 40 Active Range (nm.)

std dev 54.45

Delta Range (m)

68

.

Encounter 10

N49 and N40 maneuvering to landings

69

MIDDS

-20

-30

-70

-80 - 40

06/l 7/l 999 21 :14:14 -21:22:42 . . . . . . . . . . . . . . . . ..__...................____.._....__________._...-_-......-...

. . . . . . . . . . :_ . . .___.....:

x104

50 60 70 80 nmi. east of reference

90 100

21:15 21:16 21:17 21:18 21:19 21:20 21:21 21:22 time GMT

70

Rangebetween N40andN49on17-Jun-1999

35

30

15

10

5 21:14:00 21:15:00 21:16:00 21:17:00 21:18:00 21:19:00 21:20:00 21:21:00 21:22:00 21:23:00

time

.

!

.........

I ........

: ........

:.. .

, . ,

,......._..._.

.f..,......Ti..

. . . . .

._....

.._...

. . . . . .

. . . . .

..:-........-:.....-.-.-1....-..--.

..i.*........i...-.*----r..- ......

..; ......... ..r . ..-..----.:.......-.

27

....................... ..____.__ . .

71

100 I

Active - Interpolated Passive Ranges I-/-Jun-1999 21:14:14 -21:22:42

own aircraft :n49, target aircraft :n40 I I I

. I

. . 80 - l . .

l l *. l .

E 60-

. . * . . l . .* l ** .’ .

is

. . . . l - .

. .

Ei 40 - . . ’

l 8. . . . .

a l l .* . . l * . l : l , , l ,. .

. . J$ : . . . . .

. l .

g 20 - * : l *

. l .** . . l * l * . ’

. . . l .

. . . .

-20 ’ I I I I I 7100 7200 7300 7400 7500 7600 7700

100

80

E 60 is 2 40

1 20

0

-20 -

System time (set)

.’ I I I I I I

. . l . .

b l .

.

l *. : . l *- . . .

. . . l . .

. . .

. z.

. .

0. l

. l l .

l . .*., l . 0. . .

. . . . g .

.* . ‘i

. . . .

.

. l . . .

. l l * . *. l .

. .

. .* . .

. . . .

5 10 15 20 25 30 35 40 45 Active Range (nm.)

I

mean 43.02

std dev 21.82

1

I I -200 -100 0

Delta Range (m)

72

Encounter 11

N40 and Nl89H far apart crossing

73

06/l 8/l 999 17:41:33 -17:44:42 -10

-15

-20

. - .

i

. .__.._.._.......,

. . :\: :

\: : . . . . . . . . . . .____._. ._ . . . . ._ . . . ._ ._ .__._ . ._ ._ . . . . . * . . . t . “ . . . . . . ~ . . . “ “ ‘ . ~

. . . . . . . . . . . . . . . . . . Y

-40

-45

-50 _ 0

. . . . . .

. . . . ..____


30 35 40

x104

2 1 . . . . . . . . . . . . . . . . . . . . . . ~;-.-- . . . . . . ..I I............; . . . . . . . . . . . . . i...- . . . . ..-.. I : ..... . ..... ....... .. . ....... . . ..... MO ........ ...... . .... ....... .... . . .... ............... .... .; .. . . . . ... ... ....... ... . .. ..... . .... .......... ..;. . . ... . .

0.5 -...........I . . . . . . . . . . . . . . . . . . . _ . . . . . f . . . . . . . . ..- -.; . . . . . . . . . . *.; . . . . ..__..... f . . . . .

.

0 I 1 17:42 17:43

I I 1 I 17:43 17:44 17144 17:45 time GMT

74

__

200

150

E &IO0

ii a g 5o

2s 0

-50 - 1320 1340 1360 1380 1400 1420 1440 1460 1480 1500 I<20

System time (set)

Active - Interpolated Passive Ranges 18Jun-1999 15:41:33 -15:44:42

own aircraft :n40, target aircraft :n189h

. !

. l .

r

200 I I I I I I I I I

.

. .

150- . l . .

E l .‘..*.* l l *-. $jJoo- 5 *:’

I 5 .a.’ a ST 2 5o $1 l :; . I 8 ; s O- . . x -50 I I I I I I I I I

14 15 16 17 18 19 20 21 22 23 24 Active Range (nm.)

12 - mean 83.94

std dev 42.71 10 -

8-

6-

4-

2-

0 I I

Delta Range (m)

75

Encounter 12 and 13

N40 and N189H head-on crossing before and after

76

-60

-110

06/l 8/l 999 19:06:09 -19:09:24

. . . . . . . . .: . .

. . . . . . . . . . . .

N40

. . _ . . .,-_-.

. . . . . . . . . ,.._ . . . . . . . . . . . . . . . . . . . . . ..~........... .-;-............:.............;..-..~...---~.

I I 1 I I I

-70 -60 -50 -40 nmi. east of reference

. :. . . . . . : . . : . . . . . . . . . ..‘........-...L..............

”

19:07 19:07 19:08 19:08 i9:09 19:09 time GMT

77


own aircraft :n40, target aircraft :n189h

2

b ii u a ii

o”-

E

50

0

50

00

. . . . . .

: . . . . l

. .

9 . . .

. . c l

. .

. l . .

+-. . l : . .

. l *z. l

.* l ** . . . . . . l .

.

. . . . .

. .

50 I- 6400 6450 6500 6550

System time (set) 6600 6650

50 I . I I I I I I . .

. . . . .

. . : . l

l .

. .

O- o- l . .

. . . . . . . .

. . . . l . l .

. . : . . .

l *

-50 - ;* l l “. .

. . .

. l .

-50 - . . l + . . . l

. . . 0’ . . . . . . . . -0 . -0

‘..e- ‘..e- . . . . . . 0. 0. . .

. .

. l . . . . . . . .

-100 - -100 -

. . . . . . . .

. .

. . . .

-150 - -150 I I I I I 1 I 5 5 IO 15 20 25 30 35 40 45 IO 15 20 25 30 35 40

. .

12

IO

8

6

4

2

0

I-

,-

I_

I-

Active Range (nm.)

mean -50.416

std dev 32.98

I I

0 Delta Range (m)

100 200 300

78

.

-60

-70

-110

06/18/1999 19:11:11 -19:13:18 . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . . _ . . ~ . I . . . .

k 189H

N40

-90 -80 -70 -60 nmi.east of reference

-50 -40

i . . . . . . . . . . . . . . . . . .

0’ I 19:12

I 1 I 19:12 19:13 19:13

timeGMT

79

Active - Interpolated Passive Ranges l8-Jun-1999 17:11:11 -17:13:18

own aircraft :n40, target aircraft :nl89h

E250 % 2 200- cc cd = &50-

IOO- 0

300

E250 Fi 53 200 u cd = d 150

. . . . I l .-

.* l

,.- .

.

. .

l .

.

.

. . .

. .

.

l .

.

. . .

.

System time (set)

.

I I I I I .

-a. =.* .

.- . a---

. . .

l . . .

. l . . .

. . . .

. . .

.

. . . .

I I , . I I

IO 15 20 25 30 35 40 Active Range (nm.)

7 I I I

6 - mean 217.83

std dev 48.59 5-

4-

3-

2-

l-

-3000 -200 I -100 I 0 1 100 200 300 Delta Range (m)

,

t

_

80

.

Encounter 14

N40 and N189H head-on crossing with slight turn by both aircraft (same track)

81

-15

-35

-40 - 50

. . . , _’ . . . I

. . . . . _ ..: .

06/18/1999 20:10:52 -20:14:18 . . . .._..I.......t.....l.............t........_.......r..i.~.

. . . . . . ..‘...............r...........‘............rl..........r..~

. . . . . . . . . . . . . . . . . . . . ..)...........................~....... ~.__:

._.....*l.

. . .

. :

55 60 65 70 nmi.eastof reference

75 80

x10” I :

2 c ..; . . . . . . . . . . . . . . . .’

:......

... ..;. ........................ . .... NM : .............. ............ .” ...... ..l.....“. .“I.. .... ..“.“...:“.“.” .............................. .I ..... .; ...............

g 1 -5 z.c*.;*f**;.;~ :.;.:.,.:.r.;,; ;..gjpJJ&. .: ....... ............................................................... .:. ...................... : ...... ............ ....... ............ ....... . ...................... . ...................

* .g (d

I- ..i.. .................. . __i.. ..................... . ....................... [. .....

0.5~.;.......................~.......................~..................~....~ ......

01 i 2O:ll

I I I 20:12 20:13 20:14

timeGMT

82

300

200 -

E

g) IOO-

5

u

a O- 22

z -100 -


own aircraft :n40, target aircraft :nl89h 1 I I I

.$. 0 .

. l a.- l . . l

-. -a - . . - .

. . . .

. . l - .

.

f

: . -a l

c a.. l a* -a

. l . w- l . --.a l a-

.--. a.- l

1. .a* l

l -a l -

.- . .a

a-- -a *-

a.. l - .-a .

i .

-a . .

-200 ’ I I I I I 3550 3600 3650 3700 3750 3800

System time (set)

300

200

E g) 100 s IT a 0 = 2

-100

IO

a

6

4

r!

I 1 I I I I I I I

l . -a . .

. l . .-

. .

. . l .

. . . . . * .

. .

--a . .

. .

.

-i

0

.- a- .

.

-a l . . . . .

: -a

. l -aa l l .

. . a- . . .

. l . -a l

. .

- -a a. .- l l - . . . l t

a-. a- .-

. .

. - a-

.

. . -a- . l .

i

I I I I I I I I 1

0 2 4 6 8 IO 12 14 16 18 20

r Active Range (nm.)

I

mean 13.744

I I I

std dev 126.8

-300 0 Delta Range (m)

i

83


own aircraft :n40, target aircraft :nl89h 50 I I I I 1

. . . .

E O . . . . . . a- .

l .

zh

. . .

. .

. l .

g -50 - -a . . .

. a- . . l .

.

2 . . . . . l .

8 -100 -

. . l - . l . .a

. . l

. . :

. l .

. .

. . a- l

.

. . . . l

. .

-150 I I I I I 3580 3600 3620 3640 3660 3680 3700

System time (set)

.

. . . . -a

. . . . .

. : . . .

. .

-150 1 I 1 I . I 1 I I I I 0 2 4 6 8 IO 12 14 16 18 20

IO r

8

6

Active Range (nm.)

mean -65.771

std dev 45.94

0 Delta Range (m)

84

280

Active - Interpolated Passive Ranges 18-Jun-1999 18:12:51’-18:14:18

own aircraft :n40, target aircraft :nl89h

260

g 240

$220 5 5 200

&80

. . .

.

. .

.

. .

.

.

160 . . .

. I I I I I I I I I 140 1

3700 3710 3720 3730 3740 3750 3760 3770 3780 3790 3800 System time (set)

280- . I I 1 I I I I . .

260 - l s

. .

E240 -

g220 - .

. 5

. .

2 200 - .

. . .

g 180- . . . .

.

160= . .

1401 l I I 1 I I I I

2 4 6 8 IO 12 14 16 18 Active Range (nm.)

5 I I I I

mean 208.75 4- std dev 39.21

3-

2-

l-

-3000

I -200

I I I

-100 0 100 200 300 Delta Range (m)

85

Encounter 15

N40 and N189H diverging at right angles far apart

86

.

-10

-20

-40

-45

-50 - 20

06/l 8,1999 20:48:12 -20:50:40 ..,....*..........-.-‘............................;....iI.......--..r..........

. . , . . _ .

. . . . . . . . .._.


50 55 60

I I 20:49 20:49

I 20:50

time GMT

I I 20:50 20:51

87

250

200

E $50 5 u g 100

B : -a ::

50 - .

0 I I I I I 1 1

I


own aircraft :n40, target aircraft :nl89h I I I I I 1

. .

. . . . . .

. l . .

. l - . . .

l .-. I .

i -a- .

.

.

.

5820 5840 5860 5880 5900 5920 5940 5960 5980

.

System time (set)

250

. . . .

. . . . . l .

. .

. . l - . .

** . .

: : -.: . .

: l t- . .

OL 20 22 24 26 28 30 32

Active Range (nm.)

7- I I I

6- mean 113.51

std dev 42.7 5-

4-

3-

2-

l-

0, I I I

34 36 38 40

-300 -200 -100 0 100 Delta Range (m)

88

Encounter 16

N40 overtakes N49 during departure

89

-30

-40

-70

06/18/l 999 17:30:00 -17:37:04 ‘.._........._-.......................~~.-.~.......~~~~~~.

\

. . . . . . ..__..... . .._______.

. . ..____.....

. . . . .

. .

. .

. .

. . . . . . . . . . . . . . . .

. . . . . . . . . . . . . ...*

Miram& NAS !3K 40 50 60

nmi. east of reference 70 80

x104

2 -...........I .*.....-.. -i . . . . . . .._.i ;.-+ -=..... -; . . ..___..._. . ..___ -4 ___..__...;

g1.5 -.,.....,=.. f =...... -.--[ . . . . . . . . -+ . . . . ‘ . . . . +..- . . . . -**; ..____” ____; .._.__ . . . . .

:

. . ‘1. . . ** ..-’

. s 1 - . . . . . . . . . . . . . . . . _ . . . ..- :...-- . . ..__. ____.*..... :.

) . . . . t..:::::.’ . . . . . . . .a;* ‘;~.~..‘...‘. ..*... T.:r rr. . 1 ) . . . . _ . . . . ;

a . . . ...-.’ .*- . ..- .

. . . . . . . . N49’ - - - * * * * ..: . . . . .-* .

: 0.5 -....... *..-I . . . . . . ..%.L. :.._ ..;.. 1 .*.. y?.::‘....... ;.~..- . . . . ..I ._....... -.; __._._.._._;

. ** . .*:a .’

. ..*

A30

*...N4:.“” ; I I I I I 1

17:31 17:32 17:33 17:34 17:35 17:36 17:37 time GMT

90

100 I


own aircraft :n49, target aircraft :n40 I I I I I I I

l

E

50- l l . . a. . . . l -

a... .

. l -. . . . . a. a-

. -*a l

-.. l -a

.

E-i 0

a-- . -a .

. . . a- a-

l .

Ei

- . . . l

. l .-. .- .

. -a

. l . . . u

.

a -50 - . l

=

23

-100 -

.

I I I .

-150 I I I I I

2650 2700 2750 2800 2850 2900 2950 3000 3050 3100 System time (set)

. . . ;-

. .;, -- l

. .t

a- .

:?.a .a-. .

a-

-.-. . a.

. - a. -

.- .

.

. l - :. . .

. l

.a- - .

. . . .

. .

.

I I I I .

I -

7 8 9 IO Active Range (nm.)

11 12

15

IO

5

mean 10.352

std dev 31.71

13

-300 -200 -100 0 Delta Range (m)

100 200 300

91

Encounter 17

N49 departing, N40 departing behind at right angles

92

-30

-35

-40

-60

-65

-70 - 30

Y

.

2

06/l 9/i 999 20:37:00 -20:40:00 . . . . _ . . . . . . . _ . _ . . . _ _ . _ _ _ . . . _ . _ _ . . ~ . . . . . . . . ~ . . . . . . ‘ . . . . . . . . . . .

\

l.i.t.r..._ .._.r.__.f.____..._._.............‘.~__..__.,._._.

\\

I\: : : : :

. t . . . . . . . . . . . _ . . . . . _ . _ _ . _ . . . . . . _ . . . . _ . ~ . . . . . . ~ . . l ~ . * t . . . . . , _ .

; \

: \ :

. .) . \ . . . . I\ . . . . . . . .._.. ..N4-9

x IO4


60 65 70

Miramar NAS

. . . ..‘.....-‘...........*..r...........:........-.....‘.....-........‘.............~

. . . . . *m..*. . . . . ...’ ..a . . . . ..* . . . . ** . . . . . . . . . . . . 1. . . . . . .ns. o . ..‘ . . . . . . . .- ’ ‘. . . . . . . .... . . . . . -y I N40 :

. . . . . . . . . . . . . . . . . . . . . i “... “. . . . . . 1.o.s .w. ..* . . . . .

200:37 I I I I

20:38 20:38 20:39 20:39 20:40 20:40 time GMT

93

21

20.8

20.6

20.:

2(

'2%

Rangebetween N40and N49on19-Jun-1999

. . . .._.._.___. \..+

I

......_....I.‘,...,_....

____.._____...___._.....

‘:OO 20:37:30 20:38:00 20:38:30 20:39:00 20:39:30 20:40:00 20:40:30 time

94

180 I


own aircraft :n40, target aircraft :n49 I I I I 1 1 1

60 - . .

. . 40- ’ l . . l * l . .

. .

2(-)- 8; .-=** l l

.

.

.

* . . l . .

.* .

oo- l . .

. .

l

80 - .

60. 760

I 780

I 800

I I I I 1 I 820 840 860 880 900 920 940

System time (set)

1801 I I I 1 1

160- l

E,40-. l l * . . . .

i%

. . . . l . .

s 120- l

. .

. . .

. l .I

CT

.

. . l .

;

g loo- .I

. . . . .

80 - .

60 I I I I I 19.8 20 20.2 20.4 20.6 20.8 21

Active Range (nm.)

20

15

10

5

I

mean 120.3

std dev 16.78

I I I I

0 -300 1

-200 I I n _I

-100 0 100 200 300 Delta Range (m)

95

Encounter 18

N49 crosses at right angles in front of N40

96

b

0

-5

-10

-30

-35

-40 - 0

LAX 06/19/1999 20:51:45 -20:55:00

,____L.____ ‘._~~~........~._...1.‘~........1...‘.‘................~.~.......

. . . . . . . . . L._ . . . . . . . . . . . . . . . . . . . . . ..__.__............‘........._.

. . . . ..lr~~.................I....j.......I..l.......L......

3 \I .‘~““.~“-;““.‘.“.‘.‘.‘.“““““..‘.......,..’..””.““““““‘........

4 I I I I I I I I

5 IO I5 20 25 nmi.eastof reference

30 35 40

0 i I I I I I I 20:52 20:53 20:53 20:54 2054 20:55 2055

timeGMT

97

RangebetweenN40andN4!3on19-Jun-1999 16

14

12

8

6

20:

,,i..~-r-_~_~-_i-_ii~/_j ,........._._. :.. ,, ,,

-

:30 20:52:00 20:52:30 2o:m:oo 20:53:30 20:54:00 20:54:30 20:55:00 time

98

Active - Interpolated Passive Ranges I8Jun-199920:51:45 -20:55:00

own aircraft :n40,targetaircraft :n49 160- I I I I 1 1 I I I

. .

140- .

. . .

E . . .

l . l . . l .

&120- . 0.’

Es . l .- . . .

. . 0. l

.

[I:

.

g IOO- . l '.' .*m** :

.

l

. . . . .

2i

. l

1 -..*. .

60 *'

. I I I I I I I I

1640 1660 1680 1700 1720 1740 1760 1780 1800 1820 1840 System time (set)

. . . . . . 140-. l 140-. l

. .

E l * E l * . .

g 120 ;=:::* l g 120 ;=:::* l

. . . . . . .

gr 0.9 . gr 0.9 .

. . . .

. . .

u u

. . .

g loo-' l . g loo-' l . l . l l . l

l * . l ; l . l * . l ; l . .

. . . . . . 2 2

. . . . . . . . l . l

80- . . ..* / l 80- . . ..* / l

. .

. . . .

. .

60 60 I I I I I I I I I I

4 4 6 6 8 8 IO IO I2 I2 I4 I4 I6 I6 Active Range (nm.)

20 1 1 I I I

mean 106.25

15 _ std dev 20.38

IO-

5-

-3000 I

-200

I I I

-100 0 100 200 300 Delta Range(m)

99

Encounter 19

N49 departing, N40 departing behind at right angles (same as Encounter 17)

100

06/I 9/I 999 20:37:00 -20:40:35

-40

-70

N49

. . . . . . . . . . . . . . ..I............_

. N40

40 50 60 nmi. east of reference

80

x10”

I 2

I . . . . . . . . . . . . . ..;_. . ..I., . . . ;.. . . . . .

El.5

I

...C_ . . . . . . . . . . ..I . . . ..______........... ;..~ ._........_.._.._..~ .,..__..____

s g , a

. .~. . . . . . . . ” ; . . . I.. ;,.,.;; .;, ;.; .;. ;.* ;.i ,i,r ..,._. “““..j ._.. Y..: .: ~‘:‘“‘.?:‘:’ . . . . . . . . . . . . . ..a- ..,. Fla;g”... L”’ ,.,* .I... .” -9 ““‘“““. . . . . “.. . . . . . . . . . . . . ..““. - .” ***

;

0.5t. . . . ..I................ . . ..l................. 1‘ . . . . . . . . . . . . . . _ . . . . . i . . . . . . _ . ..-.

. . . ..i ” . . I.“.“.... “. . . . . . . . ..I “.. . . .” . . . .A. . . . . “. . ..““.. . ..,... . . .

-*““*

. _..... .“a”. ““.I... -“: .I ..** . “.. . . . “. “. .“. . . . . . . . . .

N40 ..L . . . .

2::37 1 I

20:38 20:39 20:40 time GMT

101

200

150

E

Active - interpolated Passive Ranges 19”Jun-I 999 20:37:00 -20:40:35

own aircraft :n49, target aircraft :n40 I 1 I I

$j)IOO- 2 E

. . g 50

. . . . . . . l . .

-0.. l

. . . . .

6

. . . l l :*

. . l * . - .

.

O- .

.

. .

-59 350

I 400

I I

450 500 System time (set)

I

550 600

.

200. I I I I I

.

150-

z &loo- s cc

. . (d 50 -* l l * 0. zz . . . .

k!i l

. . .

. . . .

. l l *. : l *. . .

l .

. .

.

O-

. .

. .

-50 19.8

I 20

I I I I

20.2 20.4 20.6 20.8 21 Active Range (nm.)

12s I I I I

IO- mean 34.791

std dev 27.39

8-

6-

4-

2-

-3000 I

-200 I I I I

-100 0 100 200 300 Delta Range (m)

102

Encounter 20

Right angle departing

Continuation of right angles departing ending with “U” turn by N49

103

-5

“IO

. . . . . . . . . . . .

. . . . . . . . ..__._......

-30

-35

-40 _

.................... :1\, ! .......... .........

0

06/I 9/I 999 20:53:10 -20:53:26

. . . . .

. . . . . . _..._ . . . . _ .

. . .

. . .

.

~..Y . . . . . . ..i . . . . .._.. I . _

. . .

. . .

.

. . . . . . . . .._._.._._________.

5 IO I5 20 25 nmi. east of reference

30 35 40

x10”

2 I . ..I..... _ . . . . . . . . _.__.__ -........_._. __ . . . . _ . . . . . . . . . . . . _ . . . . . . . . . . . . . . __ . . . . I

c - ...... ; . gI.5 .... i .. ..i....,....,...., ........................ /. ....................... , ....

g g , . . . . . . . . . . . . . . . . . . . ..- _.._ . . . . . . . ..I. i . . . . . . . .._. m

I 0.5 1.. . . . . . . . . , . . . . . . . . . . . . , . . . . . . . . _ _. . . . .

2&53 20:53 time GMT

104

06/I 9,I 999 20:53:43 -20:58:33 2c

IC

C

8 s -i 2 -5 "IO c 2 E .-:

5

-20

-30

-40

. . . L _ . _ . L . . . . . . . . . . . - . . . . . . . _ . . . . _

_ . *.__.

-20 0 10 20 30 40 nmi. east of reference

x104

2 I I .,..I . . . . . . . . . _ . . . . . . . . . . . .._. _ . . . . . . . . . ..__-= ~_.i . . . . . -.:-...- . . . .._...... I . . . .._ _. - : ” I’” t

-d- - ~I.5ccT-jC:.~..!!? . . . . . Jo . . . . . . .._...._.. j . . .._........__. iS..-v-.p.- _...__ i ___._._.

s g 1 ca i 1

. . i . . . __..__r . . .

0*5-.~..f . . . . . . . . . . . . . . . . 1...~ .I...........; . . ..--..--......-. . .._.... --...-.-; .__. _._.

0 i 20:54

I 20:55

I 20:56 time GMT

I I 20:57 20:58

105

60


own aircraft :n49, target aircraft :n40 I I I I I 1 I I I .

.

2 4o 7- * : .

. ? -20 I I I 1 I I I I I

14 16 18 20 22 24 26 28 30 32 34 System time (set) System time (set)

60 60 1 1 I I 1 1 I I I I I I I I . .

. .

g 4o g 4o t t : :

s s I l I l

.

2 2 20- 20- i cl3 cl3 I I I= I=

iii o- iii o- i i I I

-20 l ’ -20 l ’ I I I I I I I I 1 1 I I

4 4 4.1 4.1 4.2 4.2 4.3 4.3 4.4 4.4 4.5 4.5 4.6 4.6 4.7 4.7 4.8 4.8 Active Range (nm.)

20 I I I I I

106


own aircraft :n49, target aircraft :n40 100 I I I I I I

. .

.

. l 80 -

E :!

l . . . . l .

330-.. i;

. . .* ”

l * l . .* *

2 f- . : . . cc m;: 0. .

3 40 .:a .

t 0” .

. l . . .

20 - .

0 0

1 50

I 100

I I 150 200

System time (set)

I I 250 300 350

20

t

. .

.

-5 10 15 20 25 30 35

25 I I I I I

mean 57.132

std dev 16.81

Active Range (nm.)

1

0 Delta Range (m)

107

REFERENCES

1.

2.

3.

4.

5.

6.

7.

8.

ICAO, Amendment No. 73 to the International Standards and Recommended Practices, Aeronautical Telecommunications, Annex 10 to the Convention of International Civil Aviation, Volume IV (Surveillance Radar and Collision Avoidance Systems), adopted by the Council of ICAO on 19 March 1998.

Federal Aviation Administration, Measurements of 1090 MH.. Extended Squitter Performance in the Los Angeles Basin, Final Report, DOT/FAA/ND-00/7, May 2000.

D. Jonathan Bemays, Steven D. Thompson, William H. Harman, Measurements of ADS- B Extended Squitter Performance in the Los Angeles Basin Region, Proceedings, lgfh Digital Avionics Systems Conference, Philadelphia, PA, October 7-13,200O.

RTCA, Minimum Operational Performance Standards for 1090 MHz Automatic Dependent Surveillance - Broadcast (ADS-B), RTCAIDO DRAFT, 12 May 2000.

RTCA, Minimum Operational Performance Standards for Air Traffic Control Radar Beacon System/Mode Select (ATCRBZMODE S) Airborne Equipment, Document NO. RTCA/DO-18 lB, July 1999.

Harald Wilhelmsen, Distance Calculations for Flight Data Processing, ATC Project Memorandum No. 41PM-Oceanic-0004, MIT Lincoln Laboratory, Lexington, MA, 18 June 1997.

U.S. Department of Transportation, Numerical Studies of Conversion and Transformation in a Surveillance System Employing a Multitude of Radars - Part I, pp. 5-7, Report No. FAA-NA-79- 17.

Elliot D. Kaplan, Understanding GPS, Principles and Applications, Artech House Publishers, Norwood, MA., 1996.

109

comparison of active tcas slant range measurements with ... · tcas on all commercial aircraft with...

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