status of gps/loran prototype for faa trials by james h. doty and patrick y. hwang, ph.d., rockwell...
TRANSCRIPT
Status of GPS/Loran Prototype for FAA Trials
by James H. Doty and Patrick Y. Hwang, Ph.D., Rockwell Collins, Inc., Linn Roth, Ph.D., Locus, Inc., and Mitchell J. Narins, Federal Aviation
Administration,
Portions of this work are being performed under subcontract SK-00-18 between Locus, Inc. and Advanced Management Technology, Inc. (AMTI) and under subcontract SK-02-02-001-00 between Rockwell Collins, Inc.
and AMTI under a Federal Aviation Administration (FAA) Broad Information Technology Services (BITS) contract.
Outline
• Interest in Loran
• GPS/Loran Integration Program
• Program Status
• Breadboard System design and test results
• Brassboard System features
• DOT’s Volpe Center study on GPS vulnerabilities spurred interest in independent, backup systems for both navigation and timing, i.e. critical infrastructure areas
• USCG interest in harbor entrance and approach• FAA interest for NPA (Non-Precision Approach)• Since 1997, Congress has provided $69M to further Loran
development, and estimate $21-25M in 2003• Loran infrastructure upgrade well underway, and overall
system performance will improve when upgrade complete
Resurgence In Loran Interest
GPS/Loran Integration Program
• The FAA is funding efforts to develop resources to evaluate and demonstrate the use of Loran to enhance the integrity and continuity of airborne navigation systems
• Rockwell Collins and Locus are under subcontracts to Advanced Management Technology, Inc. (AMTI)
– Locus is leading the effort to develop a prototype combined GPS & Loran H-field antenna and a standalone Loran receiver
– Rockwell Collins is leading the Integration of a Locus Loran receiver into a Collins Multimode Radio (MMR)
GPS/Loran Integration Program
Locus
Rockwell Collins
GPS/Loran Antenna
Brassboard GPS/Loran
Breadboard GPS/Loran
Loran Card
Standard SatMate 1020
Loran Receiver
StandardGNLU-930
MMR BreadboardGLIP
Loran CardICD GLIP Card
GPS/Loran Integration Effort
GPS/Loran Antenna Development
GPS Antenna Requirements
H-Field Loran Antenna
Loran Receiver
• Develop Eurocard size SatMate 1030
• Develop combined GPS/Loran H-field antenna
• Support Rockwell MMR integration
• Deliver prototype systems to FAA and Rockwell and support FAA tests
• Program efforts began January 2002
Locus :• Develop interface definition for
embedded Loran card • Perform integrity analysis and
develop integration algorithms• Integrate Locus Loran receiver
into Multimode Receiver (MMR)
• Support Locus antenna integration
• Deliver prototype system and support FAA tests
• Program efforts began May 2002
Rockwell Collins :
Program Responsibilities
Locus Program Status
Eurocard SatMate 1030 prototype receiver
functioning
Combined GPS/Loran prototype antenna
functioning
Uses certified ADF radome for flight tests
Locus Program Status
Front Panel
Rear Panel
Eurocard SatMate 1030 in stand-alone enclosure
Rockwell Collins Program Status
Breadboard GPS/Loran system completed and van tested
GLIP integration processor card for
Brassboard System assembled and tested
Current Rockwell Collins MMR
MMR - GNLU-930
Other GPS users(e.g. FMS, EGPWS)
L-bandL-band GPS PVTGPS PVT GLS PANGLS PAN
VHFVHF
UHFUHF
LocLoc
GlideslopeGlideslope
ILS ILS loc/glideloc/glide
Localizer/Glideslopedeviations
/GBAS/GBAS
C-band MLS az/el
• Current GNLU-930 MMR provides Localizer/Glideslope deviation information for approach, and PVT (position, velocity, time) information for area navigation and other uses
Brassboard MMR Architecture
• Locus SatMate 1030 Loran card will be embedded into Rockwell Collins MMR
• An independent GPS/Loran Integration Processor (GLIP) card will be added to minimize development risk
MMR - GNLU-930
L-bandL-band GLS PANGLS PAN
VHFVHF
UHFUHF
LocLoc
GlideslopeGlideslope
ILS ILS loc/glideloc/glide
Localizer/Glideslopedeviations
/GBAS/GBAS
GPS PVTGPS PVT
LF Loran Integration Proc.
Other GPS users(e.g. FMS, EGPWS)
New GPS Loran Integration Processor (GLIP) Functions
• To facilitate flight test evaluation of alternative Loran utilization techniques, multiple solutions of position and integrity limits are generated and output – “GPS-only” passes through GNSS solution– “Loran-only” recomputes position solution from Loran measurements – “Federated” GPS-Loran processes Loran and GPS measurements but
maintains independence between sensors for improved integrity– “Integrated” GPS-Loran calibrates Loran errors using GPS and produces a
more accurate position solution
GNSS I/O
Loran I/O
GPS-Only
Loran-Only
Federated GPS-Loran
Integrated GPS-Loran
Output I/O
ARINC I/O
Breadboard GPS/Loran System
J3
J2
J1
LoranAntenna
Cable 115VAC60 Hz
GPSAntenna +28VDC
CB2CB1
Data J4
DataJ5
GLIPProcessor
BoxLoran
RS-232
GNSS ARINC
GPS Loran
Nav OutputsGPSLoran
Serial Port #4
Loran PCControl
GNLU-930
WOW
ARINC
PowerSupply
Power Strip
Locus Satmate
Antenna
Serial Port A
J3
J2
J1
LoranAntenna
Cable 115VAC60 Hz
GPSAntenna +28VDC
CB2CB1
Data J4
DataJ5
GLIPProcessor
BoxLoran
RS-232
GNSS ARINC
GPS Loran
Nav OutputsGPSLoran
Serial Port #4
Loran PCControl
GNLU-930
WOW
ARINC
PowerSupply
Power Strip
Locus Satmate
Antenna
Serial Port A
GNSS
RS232 I/O
GLIP Functions
IntegratedSolutionARINC 429
Loran-OnlySolutionARINC 429
GPS-OnlySolutionARINC 429
Combined Data RS-232
ARINC I/O
Loran
Integrated GPS-Loran
Loran-Only
RS232 I/O
ARINC I/O
ARINC I/OGNSS
RS232 I/O
GLIP Functions
IntegratedSolutionARINC 429
Loran-OnlySolutionARINC 429
GPS-OnlySolutionARINC 429
Combined Data RS-232
ARINC I/O
Loran
Integrated GPS-Loran
Loran-Only
RS232 I/O
ARINC I/O
ARINC I/O
• Takes data from unmodified GNLU-930 MMR and SatMate 1020 Loran Receiver
• Recreates Loran Position solution from Loran timing measurements
• Produces an integrated GPS-aided Loran Solution
• Solutions available on both ARINC 429 and RS232 output formats
Breadboard Pallet I/O
110V AC 60 Hz
28V DC
Input powerOutput Data
ARINC 1 GPS onlyARINC 2 Loran onlyARINC 3 GPS/Loran
RS232 Combined data for collection
Loran H-field Antenna
GPS Antenna
GPS/Loran Breadboard
Antenna Connections
• The Breadboard GPS/Loran (GPS-aided Loran) solution is a Loran solution corrected with ASFs calibrated using GPS PVT data
• RS232 output includes ASF correction data, all three position solutions, and raw Loran Data messages
Breadboard Loran-Only Position Solution
-300 -280 -260 -240 -220 -200 -180 -160 -140 -120 -100-200
-180
-160
-140
-120
-100
-80
-60
-40
-20
0
No WeightingAmp WeightingPower WeightingLocus Reciever
-300 -280 -260 -240 -220 -200 -180 -160 -140 -120 -100-200
-180
-160
-140
-120
-100
-80
-60
-40
-20
0No WeightingAmp WeightingPower WeightingLocus Receiver
With only three stations weighting does not
change position solution
With more stations the weighting algorithm has a significant impact
on estimated position
Revised weighting algorithm overlays Locus
solution
• Extensive work was required to reproduce the Locus position solution from the delta-time measurements – Locus provided implementation details of the Locus weighting
algorithm– Position solution differences consistently well under 10 meters
Original Collins
Weighting
NoWeighting
Breadboard Van Testing
• The Breadboard GPS/Loran system was tested in the Collins Mobile Navigation Lab Van
• The antenna mount was raised to reduce interference from other van systems
Breadboard Position Outputs
42.027
42.028
42.029
42.03
42.031
42.032
42.033
42.034
42.035
42.036
-91.662 -91.66 -91.658 -91.656 -91.654 -91.652 -91.65 -91.648 -91.646
Longitude
Lat
itu
de
GPS-aided
Loran-only
GPS-only
Locus
100x100m
Breadboard Van Test Results
The GPS-aided Loran solution is corrected for position bias errors, but has noise characteristics matching the Loran-only solution
GPS
GPS-Aided Loran
Locus Loran Solution
GLIP Loran-only
100m
100m
Highway Breadboard Van TestingVan Test Results
42
42.05
42.1
42.15
42.2
42.25
42.3
-91.95 -91.9 -91.85 -91.8 -91.75 -91.7 -91.65
Longitude in degrees
Lat
itu
de
in d
egre
es
GPS-only
Loran-only
GPS-aided
Locus
1 km X 1 km
Van Test Results
42.2
42.21
42.22
-91.86 -91.85 -91.84 -91.83 -91.82 -91.81
Longitude in degreesL
atit
ud
e in
deg
rees
GPS-only
Loran-only
GPS-aided
Locus
1 km X 1 km
Passed under power lines
Start
End
Turn
GPS-aided Loran solution tracked GPS position well except for a brief anomaly when the van passed under high-voltage power lines
1 km
1 km
Average North Pos.
Offset
Average East Pos.
Offset
North Position Noise
East Position Noise
Locus receiver solution (no ASF corrections)
-164.3 -195.6 20.9 26.6
GLIP Loran-only solution(no ASF corrections)
-164.0 -196.4 20.9 26.8
GPS-Aided solution -2.0 -1.4 18.8 24.3
Typical Van Test Results
Van test solution errors relative to GPS in meters
GPS-derived ASF corrections dramatically reduce position error
in GPS-aided solution
ASF corrections do not significantly reduce noise
GPS-aiding Loran corrects slowly-varying ASF errors of Loran but a more tightly integrated solution is required to reduce noise
Brassboard System Features
• The brassboard system will integrate the Breadboard system functionality into the standard GNLU-930 MMR form factor
• Brassboard will include Locus SatMate 1030 prototype card and Collins GLIP card
• The integrated solution will be more tightly coupled to GPS to improve noise when GPS is available
• A new Federated GPS/Loran solution will be added for improved integrity monitoring
• All outputs will ARINC 429 and RS-232 monitor port will be eliminated
Brassboard MMR System
• Locus Loran card will be installed in place of the MLS slice on door of a modified GNLU-930
GLIP
Loran
MMR – Added Cards
• The new Collins GPS Loran Integration Processor (GLIP) card will be installed in the center card cluster in place of the FMS slice
• A ribbon cable from the GLIP to the Loran card will provide power and data communications
MMR Card Modifications
• The ILS and other MMR cards will remain unmodified (except for minor additions to the rear interconnect card)
ILS Card Power Supply
RearInterconnect
Card System Processor
Summary
• The FAA is supporting efforts to evaluate Loran for suitability of use in NPA and other airborne navigation applications
• Rockwell Collins and Locus are participating in coordinated programs to develop demonstration prototype GPS/Loran antenna and GPS/Loran MMR– Will be utilized by FAA to evaluate and demonstrate the use of
Loran to enhance integrity and continuity• The Breadboard GPS/Loran system has been completed and
van tested • The Breadboard system is working well and performance
characteristics are about as expected• Components for both the Brassboard System and GPS/Loran
Antenna have been assembled and are being tested