Space Based Signal Intelligence Systems : Global Trends & Technologies

Dr. R. Sreehari Rao

Director

Defence Electronics Research Laboratory Hyderabad

Space Based Signal Intelligence Systems : Global Trends & Technologies

• Need for Satellite based SIGINT

• Types of space surveillance & reconnaissance systems

• Global Trends in SIGINT systems

• Salient features of satellite SIGINT payloads

• Critical SIGINT payload technologies

• Conclusion

NEED FOR SATELLITE BASED SIGINT

LIMITATIONS OF CONVENTIONAL SYSTEMS

• RADIO HORIZON

• PRONE TO MISSILE HITS

• STRAINING OF DIPLOMATIC RELATIONS

SATELLITE SIGINT PLAYED CRUCIAL ROLE IN RECENT

WARS

SPACE SURVEILLANCE AND RECONNAISSANCE

PHOTO RECONNAISSANCE SYSTEMSEARLY WARNING SYSTEMSSIGNAL INTELLIGENCE SYSTEMS

ELINT• RADINT• TELINT

COMINTOCCEAN SURVEILLANCE SYSTEMSIMINTMASINT

MISSIONS OF SPACE BASED SIGINTCOMINT

INTERCEPTION AND DECRYPTION OF MILITARY AND

STRATEGIC COMMUNICATIONS

MONITORING OF TERRORIST ACTIVITIES

ELINT

INTERCEPTION OF RADAR SIGNALS

TELINT

RECEPTION OF TELEMETRY SIGNALS DURING

BALLISTIC MISSILE TESTS

ELINTELINT INVOLVES ACTIONS TAKEN TO

• Search• Intercept • Locate • Record• Analysis of radiated EM energy

ELINT Rxs measure• Angle of Arrival (AOA) • Pulse Width • Pulse Repetion Frequency• Frequency• Time of Arrival• Scan Rate• Location fixing of emitter

COMINT

• Search, DF and intercept

• Location fixing of emitters

• Signal analysis and classification

• Monitoring

• Recording

• Evaluation and comparison with stored data

• Generation of tactical reports

Radar scenario

• Wide Spectral Coverage ( 0.5 – 40 GHz )

• Complex Waveforms

• Wide PRF Range with Jitter and Stagger – 50 Hz to 500 KHz

• Wide Pulse Width Ranges – 50 ns to 500 µs

• Variety of Antenna Scans

• Short Dwell Times

Communication Signal Scenario

• Wide Spectral Coverage ( 1.5 MHz – 18 GHz )

• Complex Waveforms (Burst, FH, DS)

• Non-Standard Data Formats

• High Signal Density

• Low SNR Conditions

• Both NB and WB Signals (FDM & TDM)

• Encrypted Signals

• Short Dwell Times

Handling emerging RF threats ?

To be complemented

Military Satellites Launched in 2006

Ref: SPACESECURITY.ORG 2006

Type of satellites for SIGINT payloads

Group name Weight

Large Satellite >1000Kg

Medium Sized Satellite

500 - 1000Kg

Mini Satellite 100-500Kg

Micro Satellite 10-100Kg

Nano Satellite 1-10Kg

Military SIGINT satellites : Global scenario

ELINT SATELLITES

GRAB (US) CERISE ( FRANCE)

US-P (Soviet )

Mission:

• Monitoring of microwave traffic

• Missile telemetry and data links

• Scud launch detection

Huge unfurlable reflector, large array of feeds to intercept

signals from different locations, to pick up signals from

radios of wrist watch size

GEOWeight : 2700 kg Antenna: 255 ft dia.

SIGINT SATELLITE (US)

Technologies

EORSAT – (Elint Ocean Reconnaissance Satellite – `Cosmos series` - Russia)

• Passive collection of transmissions

from both radio and radar units

• EORSAT constellation consists of multiple satellites in two orbital planes

• Capable of estimating naval positions to within two kilometers

Cosmos

Shenzhou ELINT

Shenzhou – (China)• UHF (300 – 1000 MHz) by three

earth-pointing antennae

deployed on long Telescoping

booms

• Seven horn antennae arranged

in an arc to detect and localize

radar transmissions

MEO

SIGINT SATELLITES• GEO – SIGINT is required for the acquisition

of continuous Signal Intelligence about the

RF threats at specific regions of interest.

• LEO – SIGINT with a group of satellites with inter communication could be a better option for periodic surveillance in the fixed regions of interest.

Typical ELINT system Architecture

Receiver PreprocessorH/W

Main processorH/W + S/W

+ IntelligenceMMI

Extract pulse parameters –Radio frequencyTime of arrivalPulse widthAngle of arrivalAmplitude

Functionality –Pulse de-interleavingPRI analysisFrequency analysisScan pattern analysis Emitter identification

Antennas

Typical ELINT Receiver sensitivity requirements

Satelliteorbit

L-bandAir search radar

ERP = 125 dBmRxg. Antenna gain (- 4 dB)

X-bandFire control

radarERP = 110 dBmRxg. Antenna gain (0 dB)

Ku-band Fire control

radarERP = 100 dBmRxg. Antenna gain (3 dB)

LEO(600 KM) - 70 dBm - 100 dBm - 110 dBm

MEO(10000 KM) - 100 dBm - 120 dBm - 135 dBm

GEO(36000 KM) - 110 dBm - 135 dBm - 145 dBm

DIRECTION FINDING TECHNIQUES FOR SATELLITE BASED ELINT

• Amplitude comparison DF Technique

• Phase comparison Interferometric DF Technique

• Time Difference Of Arrival (TDOA) DF Technique

Amplitude comparison DF Technique

PROCESSOR

45o

Beam Width = Beam Width = 360360No.of AntennaNo.of Antenna

CRYDET

LOGVID

CRYDET

LOGVID

-+AOAAOA

DIFF AMPDIFF AMP

PHASE COMPARISON DF TECHNIQUE

θ

ψ

dθ

λθπψ sin2 d

=

Time Difference of Arrival DF Technique

cos θdc=t

t

θ

d

Satellite SIGINT considerations:

• SIGINT systems on conventional platforms can be reconfigured to space payloads with space qualified components.

• A group of Micro-satellites in LEO are required to cover aspecified region. Microsatellites have the advantagesof light weight, less power consumption, low cost, missionspecific pay load configuration, distributed processing,Launch on Demand etc.

• Location fixing of the target is achieved by employingtriangulation.

• In GEO orbits huge inflatable antennas with MDF techniques can be employed for the emitter location

Technology thrust areas

* Reconfigurable, inflatable and shared apertures

* High sensitivity receivers

* Laser communication systems* Jam resistant secured data links

* Advanced signal processing techniques

* MEMS based components

* Satellite launchers

Critical Technologies

• Multi chip modules • MEOMS• On-board computing & data handling• Neural processing chips• Smart structures• Packaging & Thermal issues • Space qualification

• Excellent sensitivity and selectivity• 100% probability of interception• Capability to handle multiple simultaneous signals

• LTCC,SAW technologies and multilayer structures used ro reduce weight

Channelised receiver

Digital receiver• Simultaneous signal handling capability

• High sensitivity• Simplified RF • Enhanced parameter measurement accuracy

INFLATABLES

Array Fed Reflector Concept Using Inflatable Technologies

Inflatable Microstrip Antenna array

WB Beam Switching Antenna using RF MEMS switches

SubstrateSubstratePatch antennaPatch antenna

Main BeamMain Beam

• MEMS in antenna configuration

• Electronic scanning of the beam

• Light weight & compact size

Shared Aperture Array

• Multi fns from the same aperture

• Electronic switching

• Engineering & packaging is very critical

Frequency Up & Down Converters

• Frequency Translation for Digital Processing Applications

• SAW filtering technology

• Extensive use in IFM & DF systems

On board Processors

• ASIC/FPGA based Digital Processors

• Pulse De-interleaving with neural

network based algorithms

• DF ambiguity resolving algorithms

HTS microwave technology• Inherent low thermal noise in cryogenically cooled Components

• Very high quality factors(>109 ) forresonant structures

• Very high sensitivity

• Rugged, cost competitive Thick-film substrate

• Passive components can be buried between the LTCC tape layers, minimizing lead lengths, improving integration and robustness.

LTCC Technology

Multifunctional Structures

• Each layer of Multifunctional network performs a specificelectronic function like power, ground control, data tx

• Electronic components mounted directly on spacecraft structure without use of PCBs result in weight saving

• Cabling & interconnects are replaced by Multilayer Copper/ Polyimide film

Micro-sat cluster• Formation of Satellites that cooperate to perform thefunction of larger, single satellite

• Smaller satellites communicate with each other, shares the processing, communications & payload or mission functions

•Cluster can be configured for Radar,communications, SIGINT, Geo-location etc.

Distributed Processing

• Optimal Data transfer & parallel processing strategies are used to maximise efficiency

• On-board control algorithms are being developedto reduce ground control requirements

• Data processing from a group of Micro-satellites requiresknowledge of relative positions

Inter satellite Laser Communication

Conclusion

• Satellite based SIGINT systems play a vital role in intelligence gathering for assessing EOB

• These systems complement similar systems employed on the conventional platforms

• The technologies like MEMS, inflatables and MMICs for satellite SIGINT payloads play a critical role

THANK YOU