W MULTI-SENSOR SYSTEM (MUSS)

FOR AIRBORNE SURVEILLANCE

OF INSHORE WATERS

G. D. Hickman

1,97

Technical report prepared under Contract N000!4-76-C-l042sponsored by the Office of Naval Research, Code 462.

Reproduction in whole or in part is permitted for anypurpose of the, United States Government. This documenthas been approved for public release and sale; itsdistribution is unlimited.

November 1977

Applied Science Technology,. Inc.1011 Arlington BoulevardArlington, Virginia 22209

S r.".,.-.. .. . .

ACKNOWLEDGMENTS

The author would like to acknowiedge Dr. James Bailey,

Office of Naval Research (Code 462), for supplying the

necessary funds and guidance to complete this project. The

author would also like to express his 3incere appreciation to

the many people who contributed their time in supplying the

information on the various remote sensors described in this

report.

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•L,$ !

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TABLE OF CONTENTS

Pages

I. Introduction 1

II. Sensors 5

A. Microwave hadinineters (passive; non-imaging) 7

B. Radars (active; imaging) 8

C. Optical Multispectral Spectrometers 16(pasmive, imaging)

D. In.zdred Scanners (passive; imaging) 16

E. Infrared Radiometers/Spectrometers 20(passive; non-imaging)

F. C&meras

1. Mapping Frame Camera 22

2. Frame Reconnaissance Camera 23

3. Panoramic Camera 24

4. Strip Camera 25

5. Hybrid Cameras 28

a. Multiband Cameras 28b. Day/Night Laser Camera 29c. Solid State Camera System 30

G, Active Laser Systems 31

Ili. Summary 34

I, Conclusions/Recommendations 36

- -~-~ "

ABSTRACT

Data were assembled and listed in this report on state-of-

the-*rt aircraft sensors which could be integrated to form a

Multi-Sensor System (MUSS) for surveillance of inshore waters.

The following sensor categories are included: radars (active,

imaging), optical multispectral spectrometers (passive, imaging),

infrared scanners (passive, imaging), infrared radiometers/

upectrometers (passive, non-imaging), cameras and active laser

systems. The MUSS might be required to perform the following

missions: 1) collect data on previously uncharted areas; 2)

collect data on previously charted areas using different sensors,

and 3) collect dati for update and/or verification of archival

data. The principal beach parameters which must be measured by

the MUSS include: length, width, gradient, surf and tidal range

and nearshore currents. It is possible that the MUSS would

also be able to yield information on the type of sediment and

trafficability of the nearshore zone in addition to locating

obstacles in the surf zone and mapping the ground cover.

MULTI-SENSOR SYSTEM (MUSS) FOR

AIRBORNE SURVEILLANCE nF INSHORE WATERS

I. INTRODUCTION

Amphibious warfare is one of the most complicated ant

sophisticated forms of warfare, combining mobility anid flexi-

bility with the element of ssrprise. Perhaps no other military

operation is as concerned with its environment and as vulnerable

to the caprices of wind and water.

The principal parameters characterizing beaches, such as -

length, widtih, gradient, approach, material, surf and tidal

range, and L. rshore current are subject to change of wind,

water, and land interactions. The result is that beaches are

the most complex and dyn'inic of land forms.

aRAc-qugae bDea Ch. A-a tuavii* -m^*^ A nv 11,.- nr, 4-n ^nvP ra i a ann

if mobility and flexibility of the mission is to be maintained.

The surprise element of the mission is lost unless the collection

pTocess remains covert. A complicating factor is that the polit-

ical turmoil of the mid-twentieth century demands that U.S,

military forces be prepared to operate upon a variety of beaches

worldwide and within a very narrow time frame. The requirement

thus exists not only for maintaining data file3 on the world

beaches, but the capability to rapidly update and incorporate

data of specific parameters which are time dependent. Present

effortr for maintaining current data have not been satisfactory

1

and conventio:aal methods for near-realtime updating are too

time consuming frequently resulting in insufficient and/or

incorrzect data.

The application of remote s',rveillance of inshore waters

has the combined problems of sensing both the land formations

and the inshore waters. The optimum remote sensing system must

therefore have sensors which can both detect and identify sur-

face and subsurface conditions ans well as sensors which are

capable of supplying information on a variety of atmospheric

parameters.

A project was initiated in August 1976 by Applied Science

Technology, to investigate the design criteria of a Multi-

sensor Surveillance System (MUSS) for survaillance and recon-

naissance of tb,, inshore area. The results of Phas4e I of this

project are described in this report. Phase I consisted of a

terhnical assessment of the state-of-the-art aircraft sensors

which could possibly be integreted to form an airborne system

for inshore surveillance.

Development of the MUSS system concept requires one to

consider the operational aspects of the data collection and

reduction process. Some, but by no means all, amphibious

zoneas of the world have been charted. The utility of these

data to directly support a tactical mission is subject to

examiLnation on two accounts.

"Il accuracy of original sensor data, and

"•ii changes in beech structure in the time period since

the original data were acquired.

2

Such archival data can be useful in developing predictive

models of beaches, particularly if measurements are repeated

over a period of time. It is possible, therefore, to derive a

set of viable beach parameters. The use of either the archival

or derived data in a tactical mission requires that such data

be verified and updat- 1 just prior to the mission.

To sumnmarize; the MUSS will be required to perform the

"aollowing types of missions:

e collect new data, area previouslv uncharted,

0 collect new data, area previously charted using

different sensors, and

e collect data for update and/or verification of

archival data.

Three levels of priority for inshore surveillance have

been stated by the Office of Naval Research. These priority £LU,&ins aa aubnown in Tabla i. The application of the various

se sors considered in this study have been included in this

table. Final sensor seloction must correlate the state-of-

the-art sensors with these requirements.

3

Table I - Remote Sersirq C 4 C

Requirements for Inshore cj

Surveillance A

CJ V

tlydrograpb ic Parameter

LEVEL I

e waves

* currents X - -x

e wLnd field Y " X

e bathymetry/modeling X _ X

* btn sediment, types, transport X

* tides _ x_.

LEVEL II

o beach profile - _x A x x

e beach trafficabil-.ty x X X X X* ~ .L~I L~llf... II. - ........ ~..L .L -

*water teM u Z - A - x* atnwospheric visib4,1ity ! Ix -

* barometric xr~ssvre - - -

e channel geometry I x

e salini~ty___ x_________

LEVEL I1iI

& underwater visibility X . x

a internal waves ____,,Ix x

e marine animals -

e ve•etition - x x - -

*all weather

i4

II. SENSC!.S

A number of devices, both imaqinq arid non-imaqinq, known

collectively as "remote sensors", have been and are currently

being developed to measure electromaqnetic radiation emitted

or reflected from the earth at various frequencies, angles,

polarizations, etc. These instruments are also currently

being used aboard many satellites and spacecraft.

The -nultispectral concept qenerlly states that the

level ')f energy reflected or emitted from objects normally

v,4rie with wavelength throughout the elmct,:omagnetic spectrum.

A unique signature of a•; object can therefore often be identi-

fied if the energy that 'b being reflected and/or emitte*( from

it is separated into carefully chosen wavelength bands. Many

cofiventional systems with a wide ranqe of sensitivity tend to

inhibit object.-tc-backgqround discrimination, however, discrim-

ination capability can generally be improved by selectively

recr'zding energy from within different wavelength bands.

While this irultispectral imaging technique may appear to

be relatively simple, complications arise owing to qncertainties

or variations related to the following factors:

o spectral characteristics of the source emitter,

* the a igle of incidence of the emitter with respect

to the surface,

e selective transmission, reflf-tion, absorption,

emission, and scattering effects of the atmosphere,

5

o reflectance and emittance characteristics of the

surface,

o altitude of the sensor platform,

# data collection, processinq, and presentation

techniques, and

o data Interpretation techniques.

An understanding of these factors and the uncertainties asqo-

ciated with their distribution, measurement, and relative

importance is -.ecessary in order to enhance the ob)ect-to-

background contra3g: ratio in any rernote sensinq oper&•icin.

Voiumnous data have beor, obtained duriing #he past decad in

a wide variety of di -iplines with numerous types of sentors.

The majority o! the sensors used are those that produce imwqgezy

or photography in the wavelength bands betwen n.3 micrometers

in'the near ultraviolet to apprcxinate~y 1.3 ma..ers in i-h.

microwave portion of the spectrum. Wit.hin this relatively broad

band, sensing Pystems may include the use of cameras; optical,

infrared and microwavve scanners, spectrometers and radiometers;

as well as active laser systems. With the exception of radars

and lasers, which are active systems providinq their own source

of i.lumination, the systems operating in the bands mentioned

above are qenerally passive; that is, they record the natural

level of radiation frzm a given scene.

The following is a list of the senpor categories for

which data were assembled during this contract.

- microwave radiometers (passive; non-imaging)

6

e radars (active; imaginq)

* optical multispectral spectrometers (passive, imaging)

* infrared scanners (passive; imaging)

* infrared! radiometers/spectrometers (passive; non-imaging)

* camoLas

* a=tive laser systems

A brief description of each sensor category is given, along

with the salient parameters for the specific sensor systems in

that category. Information for this study was assembled from

a variety of sources: personal contact with key scientists

and marketing managers, NASA centers, Marine Corps and Navy

peroonnel, private companies, conferences, specification

sheeta, and technical reports and handbooks.

A., Microwave Radiometers (passive; non-imaging)rw-- •a diometry holds promise as a passive all-wcather

technique; it may have improved capabilities over shorter wave-

length sensing in detection of: ground moisture, ocean-wave

heights, and near s rface temperatures. Generally, the wave-

lengths longer than 10cm are surface penetrating and provide

good masurements of subsurface phenomena, soil moisture and

salinity. Wavelengths between 4 and 6cm provide the best

window through the atmosphere to the surface. Wavelengths

between 0.7) and 6crn are utilized to distinguish between temp-

eZature and emittance effects in the energy source such as

wind induced surface roughness and foam, the atmospheric

7

water vapor column, and precipitation levels. Wavelengths

below about 0.6 cm (750GHz) are most useful in providing indi-

cation of storms over land and of sea ice boundaries because

of their finer resolutions for a given antenna size or in

providing temperature, humidity and pressure soundinq due to

differential effects on specific absorption lines.

Table II lists the various microwave radiometers that were

identified by this study while figure 1 shows these same systems

superimposed on the various atmospheric bands. The majority ot

the passive microwave systems are large and weigh in access of

400 lbs. The only exceptions to this are 1) the S-Band radio-

meter of North American Rockwell, 2) the swept frequency micro-

wave radiometer of North American Rockwell, and 3) the elec-

trically scanning (imaging) microwave radiometer of Aerojet

General.

B. Radars (active; imaging)

Radars exist in many different confiqurations, each

designed to perform specific measurements on an illuminated

scene. The type of radar which appears to offer the most

potential for airborne remote sensing applications is desig-

nated as the Side Looking Airborne Radar (SLAR) systems. SLAR

systems can be divided into two basic classes; a) real-aperature

or non-coherent radar and b) Syrthetic Aperture Radar (SAR) or

coherent radar.

Radar provides a specular reflection from smooth objects.

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Hence, it proves to be an especially good sensor not cnly for

identifying calm water bodies (arid therefore their shorelines),.

but also for identifying rough water a-eas. Applications in-

clude the identification of oil slicks on water and estimation

of the strength of winds near the sea's surface. Additionally,

radar has been used to measure soil moisture and in identifying

both sea and lak_ ice.

The most important characteristic of radar is its ability

to penetrate clouds (i.e., to be an "all-weather" sensor) and

map terrain and water features over a broad area of coverage.

The active microwave sensors are displayed in Table Ill. The

majority of these systems fall into the category of develop-

mental systems which have been built mainly to demonstrate

feasibility of a particular design. These systems have been

flown in support of numerous research programs and, in general,

have yi elded good to excellent results. The three production

systems available are 1) the AN/APS-94D (Motorola), 2) the

UPD-4 (APD-10) reconnaissance system (Goodyear), and 3) the

WX-50 (Westinghouse). These vary in weight from 140 lbs. for

the WX-50 system to 650 lbs. for the Goodyear system. The

highest resolution system is the APD-10, which is currently

installed in the Navy Marine Corps RF-4B reconnaissance air-

craft. This system is, however, fairly large and relatively

expensive. One must ascertain that the missions demanded

of MUSS require the use of the APD-10. Perhaps, a less

sophisticated ,:ystem wouild suffice.

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C. Optical Multispectral Spectrometers (passive; iMjiMf)

The class of multispectral imaging spectrometers must be

considered for possible inclusion in any multisensor reconnais-

sance system. These systems simultaneously register data on

magnetic tape from several spectral bands, from the visibic

through the infrared region. These data are then analyzed on

ground-oased computers to extract classes (I features having

similar spectral characteristics. Examples of several applica-

tions of this new technique to various aspects of the inshore

environment include (1) mapping of aquatic vegetation, (2)

bathymetry, (3) thermal effuents and associated mass movements,

(4) detection of industrial discharge, (5) mapping oil slicks

and (6) chlorophyll distribution. Table IV lists the current

state-of-the-art multispectral imaging spectrometers. All of

these spectrometers are similar, having 5-10 bands in the visi-

ble, with some systems having a band in the thermal IR. The

field of view of these instruments is very small; in the order

of a few milliradians. Except for the prototype systems being

developed by ERIM and NASA the systems are generally small and

weigh less than 200 lbs. The two production units that are

possible choices for inclusion in the MUSS are 1) the DS-1200

series, passive line scan systems (Daedalus) and 2) the modular

multisb.ctral scanner - M2 S (Bendix).

D. Infrared Scanners (passive; im4iq )

The thermal infrared scanner (see Table V) normally has

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one channel in the infrared, located some place between 7-14,'m.

The NASA TIRS system has an additional channel to detect the

3-5um radiation. The systems are so designed that the forward

motion of the aircraft is 'used to generate an imaqe of the

tad.ation pattern. The I! sca.pners Are -seful in detecting and

mapping thermal anomalies in both the water and on land. The

most advanced prodtiction system appears to be the .AN AAD',

(Honeywell). The AN-AAD5 has been inst.alled in the Navy/Marine

Corps RF-4B reconnaissance aircraft. This system is relatively

light (283 lbs.) and should be considered as a candidate for

the MUSS.

E. Infrared Radiometers/Spectro.mters (passive; non-imaging)

This category (shown in Table VIV is reserved for non-

Imaging radiometers that are used to detect thermal radiation

in the Epecti 1 region ranging betweer 6 and l4om. One system,

the S191 Field Spectrometer System (FSS) has a second channel

to detect radiation between 0.4-2.4um. In some cases, spectral

filter wheels are used to obtain radiation values for various

spectral bands. InfrareG ra4liometers have been used for various

ocean and meterological studies to detect.temperatures to +O.1*C.

These systems are generally small and could easily be used as

part of the MUSS. All systazms listed are possible candidates

for the MUSS.

F. Cameras

Four basic types of aeiial cameras are currently being

deployed. These cameras are listed under the following cateqories:

20

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"* Mapping frame camera

"* frame reconnaissance camera

"* panoramic camera

"* strip camera

A brief description of each category is given along with

a few examples of commonly used cameras. Aaditionally, a fifth

category designated, "hybrid camera" has been introduced to

cover cameras that do not exactly fit one of the basi- generic

categories. No attempt is made to list the more than 100

different aerial camera models that are in current use. The

reader is referred to the following references* which give

listings of aerial cameras.

1. Mapping Frame Camera (Metric Camera)

Mapping cameras are all of the same basic design and

their distinctive feature is its high degree of distortion

correction. The niapping camera can be characterized as having

a wide field of view, in addition to being restricted to air-

craft usage of low v/h values.

;Cimerman, V.J., and Z. Tomasegovic, 1970, Atlas of Photo-gra-rnetrics Instruments: New York, Elsevier Publishing Co.

Data Corporation, 1965, Airborne Photographic Equipment,Vols. I, I1, and III: Report RC013200 for Recon Central,WPAFB (and supplements, Report RC076575).

Data Corporation, 1967, Aerial Camera Lenses: ContractAF33C65D-14443 for Recon Central, W'-AFB.

McDonnell Douglas Corporation, 1973, ReconnaissanceReference Manual: Prepared for Naval Air Systems Commandby McDonnell Douglas Reconnaissance Laboratory, St. Louis,Missouri.

22

One mapping camera which is widely used by NASA, is

the Wild Heerbrugg RC-10 system. This camera is described below.

RC-10 Metric Camera

FilmFormat 9-inch x 9-inchRoll Size 400 feetNo. of exposures/roll 450

Lens Wild-Heerbrugg Universal AviogonII 6-inch f4, with an angularfield of view of 730451, or aninterchangeable 12-inch Aviogonf4, with an angular field ofview of 410.

Weiglt (System) Approximately 75kg

Resoluting power 70 cycles/mm

Ground coverage From an altitude of 6.,,000 feet:1.6 x 16 nautical miles - 6-inch lens8 x 8 nautical miles - 12-inch lens

Ground Resolution 15 to 25 ft - 6-inch lens;4 to 15 ft - 12-inch lens

2. Frame Reconnaissance Camera

Frame reconnaissance cameras, in contrast to the map-

ping cameras, can no,. be characterized by a single physical

configuration. There are, however, several important parameters

that are conmwcn among this type of camera. These features are

listed below:

* high resolving power and low f-number,

e highly corrected distortion is not a requirement,

• narrow fields of view (10' to 40*),

* film widths range frijm 7F to 240nm,

23

IL

* focal lengths range from a few cm to more than

a meter - common focal lengths are 6-inch.

12-inch and 18-inch,

* fccal plane shutters, and

* used in high-performance aircraft and high

v/h ratios.

One commonly used frame reconnaissance camera by the military

is the KS-87 built by Chicago-Aerial Industries. The KS-87

camera is currently installed in the Marine Corp's Marine

Tactical Reconnaissance Squadron Three (VMFP-3) RF-4B. Speci-

fications for the KS-87 camera are given below.

KS-87 Camera

FilmFojimat 4 1 ' /2 innh v A 1 inchRoll Size 500 feetNo. of exposures/roll 1300

Lens Dayphoto3,6,12or 18-inch focal lengthNhthoto

or 6 inch focal length

Weight Approximately 30-40kg

Ground coverage (lateral)Focal Length Lens Coverage3-inch 1.5 x A/C altitude6-inch 0.75 x A/C altitude12-inch 0.375 x A/C altitude18-inch 0.25 x A/C altitude

3. Panoramic Camera

The panoramic camera is characterized by its small

24

instantaneous field of view which yields a resolving power of

over 100 cycles/mm. The large resolving power of the panoramic

camera makes it popular in photo reconnaissance. Listed below

are some of the characteristics which are common among the

various types of panoramic cameras:

* the film surface is cylindrical and the width of

the film is parallel to the axis of the cylinder,

e the instantaneous field of view is small because

the image falls onto a narrow slit irimediately in

front of the film,

* the slit length equals the width of the picture

format, and

e the slit width is usually variable to control the

exposure time.

A few panoramic cameras presently being used are give in

Table VII.

4. Strip Camera

The continuous strip camera works on the simple prin-

ciple of moving the film behind a slit in the focal plane of the

camera at exactly the same velocity that the image is moving

past the slit. Only limited developments have been made on this

camera type during the past 30 years. The lone survival in this

field is the KA-18A manufactured by Chicago Aerial Industries.

Although this camera is not widely used, many of its features

make it well-su ted for multiband use. Additional characteristics

25

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of the strip camera are:

* it has few moving parts, and these are continuous

rather than intermittant ar in other camera types,

"* very reliable,

"* an array of cameras can be readily synchronized by

driving them from a single shaft. The film rates

in each camera are therefore identical, and photo-

graphy of an area (with perfect boresighting) i3

simultaneous, and

"* the photography is continuous, so that no film is

wasted as in other forms of photography where a

safety margin of overlap is introduced.

5. Hvbr-id Cameras

a. Multiband Cameras

A number of different types of multiband cameras

have been built, however, they all operate on the same principal

- that of recording images of a scene simultaneously through a

variety of spectral filters. Excellent reviews of multiband

cameras are given in the following references* and will not be

repeated here. A list of some of the more widely used multiband

cameras is given below.

*Slater, P.N., 1972, Multiband Cameras; Photogram. Eng., vol38, p. 543-555.

*Manual of Remote Sensing, 1975, Robert G. Reeves (Editor),American Society of Photogrammetry, Falls Church, VA, vol I,p. 286-323.

28

* Nine lens (Itek)

* Model 10 (Spectral Data)

* Mark I (1 2 S)

* Aero I (Dot Products, Inc.)

e MPF (Itek)

These cameras all weigh in the order of 100 lbs. or less and

have shown to have good operational characteristics. Spectral

Data reports that U.S. Army tests comparing the Model 10 with

the KA-76 Frame Camera showed superior performance for target

detection using the multispectral camera.

b. Day/Night Laser Camera System

KA-98 Realtime reconnaissance system(Perkin-Elmer Corporation) *

Mu c. - mera A .e. Io__ped A a .. gallium

arsenide laser. The system was designed to be compatible with

the RF-4 and the RPV environment and mission profiles. The KA-98

system has been flight tested and imagery collected. The salient

characteristics of using gallium arsenide as the illuminator are:

"* spectral covertness (850nm:,

"* compactness,

"* efficiency, and

"* inherent contrast environment

"Toles, Marvin, KA-98 Realtime Reconnaissance System, Proceedings:SPIE, vol 101, Airborne Reconnaissance (1977), p. 6-9.

29

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The KA-98 system consists of the gallium arsenide laser line

scanner, video tape recorder, a TV display console and a laser

diode film recording console. The TV display console consists

of two 2000 line TV monitors, one for the moving map display

and one for freeze frame viewing and enlargement, three scan

converter tubes, and associated electronics. The total weight

of the system is under 90 lbs. A similar type of system could

be built for mini-RPV's having a size of less than 0.2ft 3 and

weigh less than 10 lbs.

The KA-98 system has been flight tested in the

RF-4 aircraft and the BGM-34B RPV. During the RPV flight test,

the KA-98 was used in a realtime reconnaissance mode. Imagery

taken by the sensor was data linked to a ground TV display

console for realtime readout of the data.

c. ESSWACS - Solid State Camera System

(P.A Automated Systems/Air force)

A new type lightweight ( 64 lbs.) camera system

has been designed and constructed for realtime wide angle

reconnaissance from low flying, high performance aircraft*.

This system is composed of a multiple lens-linear CCD array

airborne sensor head, an air to ground data link; and a ground

based, dry silver film, laser beam recording system that pro-

duces hard copy imagery on the ground within 30 seconfts of

*Barton, G.T., Electronic Solid State Wide Agle Camera System -

ESSWACS, SPIE vol. 101 Airborne Reconnaissaace (1977), p.10-19.

30

r7

data acquisition. Flight tests of the ESSWACS system is sched-

uled for early 1978. The current silicon CCD sensors limit the

system to daytime, fair weather reconnaissance. Substitution

of an YR sensor or active illumination could extend the sensi-

tivity range, permitting nighttime and all weather cperatl.on.

The salient characteristics of the ESSWACS system are given in

Table VIII.

Table VIII - ESSWACS System Characteristics

Number of lenses 5Focal lengths 18mmt1), 53mm(2), 0llmm(2)Scanning mode Link_. Scen/Push BroomFOV 1400PhotoSensor

number-type 5-Fairchild CCD-121Helements/sersor 1724 (active)data rate 10.5 megasamples/sec

Video processing AGC, band limiting. ABLCVideo bandwidth

array sample rate 10.5 megasamples/secRecorder laser beam film recorderFilm width 4.55 inches activeFilm Dry silver (3M type 7869)Ground coverage 5210ft (from A/C altitude of 1000ft)Resolution l.Sft/lp central 80% @ 100,0001m mz

2.Oft/lp central 80% @ 3,0001m/m'

G. Active Laser Systems

The airborne laser sensor is the newest of the remote

sensors described in this report. La3er systems have been

built to measure various parameters of both the atmosphere,

the hydrosphere, including the following:

"* water depth

"* water temperature

31

e water salinity

* pollutants (water and atmosphere)

e wave heights

* atmospheric pressure and temperature

In spite of the research that has taken place in this field

during the past few years, such systems have not advanced to

the point where they can be considered off-the-shelf items. As

such they Frobably should not be considered as prime sensors for

inclusion into the MISS. The laser profilometer is the most

advanced type of laser system that has been built and tested

over the past few years. Wavelengths in the order of a few

centimeters have been measured with such laser systems.

Two developmental airborne pulsed laser systems to measure

water depths have been built to date in the U.S. One laser system

L4 U& J partLr Uf nIM' acti.;.ve Passi.ve sys~tem. ThiSJ. asY*Dttii was

flight tested in the summer of 1977, with reportedly good results.

The second system, designed and ansembled at NASA Wallops Flight

Center is in the process of being flight tested. Salient char-

acteristics of this laser system are given in the following table.

Table IX - Characteristics of NASA's Airborne Oceanographic

LIDAR (AOL) System

Laser Transmitter (Neon)

wave length 5101Abandwidth 1PRF 400ppsbeam divergence 3-20mrad variable with beam expanderpeak output power lOkw

•,' 32iI

Si~ .

Receiverspectral resolution 5401+2AFOV -?20mrad, variabletemporal resolution 2.5nsecpolarizat ion av ilable for both transmitter

and receiver

Weight 1000 lbs.Power Requirements 50 ampsPerformance

altitude (max) 600marea coverage derigned to produce one data point/

20ml, +5 decree from NADIR; capabilityto '15 degree - 280km/hr.

measurement depth 6m w4ith oL (attenuation coefficientof the water)=2m- 1 ; 10m with OL'ls-1.

minimumi measurementdepth 0.5m.

33 h

III. Summary of Results

The results of the state-of-the-art study of the various

aircraft remote sensors have revealed that a number of good

aircraft sensors systems (in each sensor category) have been

successfully flown. However, this list is rapidly narrowed when

production or near production systems are corsidered. Table X

is a compilation of these off-the-shelf systems, which should

at least be given prime consideration for inclusion into the

MUSS concept. However, one should not completely limit the MUSS

sensors to those found in Table X. Several of the sensor systems

1'ited in this study, and perhaps there are others, need only

to be reduced in size and weight in order to become a prime

MUSS candidate.

Table X - Prime Sensor Candidates for MUSS

MICROWAVE RADIOMETERS (passive; non-imaginq)

"* S-Band radiometer -- North American Rockwell

"* Swept frequency microwave radiometer - North American

Rockwell

"* Electrically scanning (imaging) microwave radiometer -

Aerojet General

RADARS (active; imaging)

"* AN/AP9-94D - Motorola

"* UPD-4 (APD-l0) reconnaissance system- Goodyear

34

* WX-50 - Westinghouse

OPTICAL MULTISPECTRAL SPECTROMETERS (passive; imaging)

o DS-1200 series - Daelalus

0 M2 S - Bendix

INFRARED SCANNLRS (passive; imaging)

e AN/AAD-5 - Honeywell

INFRARED RADIOM1ETERS SPECTROMETERS (passive; non-imaging)

* S191 FSS - Block Engineering

* Filter Wheel Airborne Rapid Scan Spectrometer - Lockheed

e PRT-5 - Barnes

e Infrared radiometer - Block Engineering

CAMERAS

* A wide choice of frame and panoramic cameras are

availabDle.

e A variety of multiband cameras are available - attention

should be given Spectral Data's Model 10.

* A ne'i laser camera system (KA-98).

* ESSWACS - A solid state camera system.

35

IV. CONCLUSIONS/RECOMMENDATIONS

A number of various types of sensors were listed in section

III as prime sensors to be considered for inclusion into the

MUSS. A number of reasons went into this final selection, but

in general these systems are the most advanced, relatively small,

both in size and weight, and require minimum power to operate.

These systems have been operated with good success and the

majority are in production.

Substantial information must be supplied by the user

agency (Navy/Marine Corps) prior to arriving at a final set of

reccmmendations for the MUSS sensors. Some of the information

which must be supplied includes.

adeti •pecifications of the various missions

required for MUSS,

o ascertain the environmental parameters that are

deemed requirements - along with associated measure-

ments such as frequency, tolerance, and coverage.

This detailed assessment is required to determine the altitude

and type of aircraft. For instance, it tuay be determined that

a single MUSS configuration will not sufffice. If such is

the case, it may be possible to consider a modular approach,

in which specific sensors for a certain type of mission will

be chosen - while one or more of the sensors are replaced

for another type mission.

The type of aircraft to be deployed is the driving force

36

iL

in designing the MUSS since the aircraft determines the avail-

able sensor weight, the altitude and the area coverage of the

system. Some of the sensors identified in this report have

either been flown successfully on RPV's or could be fairly

easily adaptable to the RPV environment. The RPV's should

therefore be considered as a possible MUSS platform.

Two othc-- considerations that play an important role in

arriving at a final set of reccmmendations for the MUSS are

1) onboard realtime displays and operator interaction, and

2) telemetry and data link requirements.

Data link requirements evolve from either of two needs.

The first need is that of the tactical commander for near

realtime update of highly perishable information relayed from

the airborne reconnaissance capability to his ground command

post. The commander may also wish to re-direct the mission

flight plan or re-target an objective based on needs for

relevant data or complementary information.

The second need deriives when a beneficial trade-off can

be made for tactical aircraft configurations between large

onboard processors and minimal preprocessors with RF link

to ground processing and display equipment.

The output data rate for the sensor systems which have

been described varies ( ;er a considerable range depending

on the information density and the required readout rate.

"..•e unique imaging sensor may output data at millions

:,i bits per second. The transmittal of such high data rates

37

in realtime would require substantial bandwidth in the data

link channel whereas selected data or frames could be relayed

ever a longer period in a narrower bandwidth channel and complete

data could be recorded for detailed analysis upon landing.

Other types of sensors, e.g., laser depth finders, provide

relatively few data points with simple information.

The multiplicity of these sensors, their type, the scanning

or acquisition data rate, the internally processed output data

forrat and rate, and the required update rate required by ie

ground terminal are all basic factors which are to be coordin-

ated into a compatible data link.

The following recommendations (tasks) are, therefore,

made with regard to completing the concept phase of MUSS.

1. Ascertain the exact reccnnaissance mission(s) for a

MUSS system, including the parameters to be measured,

their tolerance and coverage (temporal and spatial),

II. determine the A/C platforms that will be deployed

in a MUSS system,

III. determine the exact remote sensors to be assembled

to form a MUSS - determine alternative systems if

more than one type of mission and/or one type plat-

form are deemed practical,

IV. the final MUSS sensors will be based on the results

of both phase I (this report) and the above mentioned

task4 (I-III),

V'. detail investigations of the A/C displays and telemetry

requiremerts of the MUSS.

38

Unclassified

DOCUMENT CONTROL DATA. R & D(Securtytp classification of fillce. brdy of abstract oand indexing annotation niujtt bte nto,~d whon he overall report ise el.r'811fjd)

I. ORIGINATING ACTIVITY (Corporate autIhor) Za. REPOAT SECURITY CLASSIF~ICATION

Applied Science Technology, Inc.ýloll Arlington Blvd... Suite 319 a.atu

rl~ington, VA 22209

Multi-Sensor System (MUSS) for Airborne Surveillance of Inshore Waters#

4,0111ISCRIPTIVIC WNTES (Type of report and inclus date&)

$a. ORIGINATOR'S REP014r NUMSERIS)

~i 4-6Cl d2 chnical Report N&,A T-7701

NR 387-090 Rd.

10~. DISTRINUTION STATEMENT

Approved for public release; distributioyr unlimited

11. SUPPLEMENTARY NOTES I, SPONSORING MILITARY ACTIVITY

Geography ProgramusOffice of Naval Research

_______________________________ Arlington, Virgni 221IS, ASISFAACT

Dana. were assembled and listed in this report on state-of-the-~art air-craft sensorswhich could be integrated to form a Multi-Sensor System (MUSS) for surveillance ofinshore waters. The fol~lowing sensor categories are included: radars (active,

camr~sandactve ase sytem. Te MSS igh bereqire toperformtefolowig mssins:rl)colec daa o prvioisl unharedarers;k&2) collect

mustbe easredby he MSS nclde:lenth, idt, gadintsurf and tidal

yi ed iforatin o th tye o seimet ad taffcablit ofthe rearshovo zonein addition to locatinp obstacles in the surf zon'e and mapping the ground ..over. F

DD VJM 473 (PAGE 1) ~_ _ _ _ _ _ _ _

S/N 10ý-507-801Secutrity Clessification

Security Cla3sificatlon

14 LINK A LINK C LINK C

Ko WO[R5wTOLC WT MOLC WY NOLE WT

Remote SensingAircraft SensorsInshore SurveillanceBeach Reconnaissance

4Q

--DD TPoEM147/3 JI'ACk) _ _ _ _ _ _ _ _

U'nclassified(PAGE 2) Security Clessflcation