746TS Wavefront Simulator with Embedded Jammers

Distribution A – Approved for Public Release AAC/PA 032305103; Distribution is Unlimited 746th Test Squadron 746TS Wavefront Simulator with Embedded Jammers Developing, Fielding, and Sustaining America’s Aerospace Force Matthew Alsleben 746 TS/TGGA DSN 349-2274 matthew.alsleben@46tg.af.mil I n t e g r i t y - S e r v i c e - E x c e l l e n c e - A g i l i t y

Overview • Background • Embedded Jammer Approach • System Verification • Results • Summary Overview Background Embedded Approach System Verification Results Summary “This briefing is for information only. No U.S. Government commitment to sell, loan, lease, co-develop or co-produce defense articles or services is implied or intended”

746th Test Squadron Overview • Evaluate guidance and navigation system performance • Laboratory • Ground • Flight testing • Vulnerability • Inertial • Full range of test support • Planning • Test pallet build up • Data collection • Analysis • Reporting Overview Background Embedded Approach System Verification Results Summary

746 Simulation Laboratory Navigation Test and Evaluation Laboratory (NavTEL) est. 1993 Overview Background Embedded Approach System Verification Results Summary

Wavefront Simulation Overview • Controlled Radiation Pattern Antennas (CRPAs) • Widely used in military applications • Increase AJ performance • Multiple Elements • Steer nulls • Antenna Electronics (AE) Testing • Multiple signals into AE • Algorithms in AE steer nulls • (# Elements - 1) nulls Overview Background 5-Box System AGHS Phase II Future Work Summary

Existing Wavefront Simulators • Antenna Wavefront Simulator is defined as the mixing of GPS and jamming signal wavefronts to a multi-element antenna system • Previous Antenna Wavefront Simulators have used cut cables or RF phase shifters and attenuators Overview Background Embedded Approach System Verification Results Summary

Embedded Jammer Approach • This approach differs from previous ones because it involves the coherent digital jammer channels to be embedded within a GPS simulator • Time delayed—not just carrier phase shift • Coherent arrival vector for GPS and jammers • No external equipment to GPS simulator required • Proof of Concept requirements included • Maximum re-use of existing assets • 5 element system • 16 L1 Jammers • 16 L1 GPS satellites • J/S ratios larger than 50 dB Overview Background Embedded Approach System Verification Results Summary

Embedded Jammer Approach • Solution included • 5 GSS 7700s with sync signal distribution unit • Configure as RF #1 + RF #2, L1 only output • Use #2 channels as digitally-generated jammers • CW or PSK (BB) • Monitor / Cal for RF #2 for high level jamming signals • Feed jamming signals into jammer input #1 • Software modification to SimGEN • System provides • 16 CW or BB jammers AND 16 GPS Satellites • L1 only • 20 MHz Bandwidth • Center frequency offset of ±600kHz (10kHz increments) • J/S ~ 59.7 dB (Spirent predicted value) Overview Background Embedded Approach System Verification Results Summary

Embedded Jammer Diagram Overview Background Embedded Approach System Verification Results Summary GPIB Signal Distribution

Embedded Jammer Calibration Overview Background Embedded Approach System Verification Results Summary • Spirent provided calibration method • Phase/Amplitude align all simulators • CIAB Cal • Carrier Phase Inter-Antenna Bias • CICB Cal • Carrier Phase Inter-Channel Bias

Embedded Jammer Verification • Verification Tests • Test 1: Null direction and depth for single jammer • Test 2: Null direction and depth for multiple jammers • Test 3: Synchronization of Jammer and GPS Signals • Targeted Test Item: Null steering AE • Raytheon GAS-1 AE • Verification Method • Reasonableness • Repeatability Overview Background Embedded Approach System Verification Results Summary

Tests 1 & 2 • One Jammer Scenarios • Choose jammer location • Freeze AE weights • Via software, cut antenna pattern • Multi-Jammer Scenarios • Choose combination of up to 3 jammers • Freeze AE weights and cut an antenna pattern • Cut several patterns with same parameters to determine repeatability Overview Background Embedded Approach System Verification Results Summary

Tests 1 & 2: Jammer Setup Overview Background Embedded Approach System Verification Results Summary

Single Jammer Case GTx2 Overview Background Embedded Approach System Verification Results Summary

Test 1 Results Overview Background Embedded Approach System Verification Results Summary • 3 Single Jammer Cases at different locations • Performance Criteria • Reasonable (for 1 Jammer Case) • Repeatable (for 1 Jammer Case)

Dual Jammer (GTx2 & GTx4) Overview Background Embedded Approach System Verification Results Summary

3 Jammer Case Overview Background Embedded Approach System Verification Results Summary GTx1, GTx2, GTx3

3 Jammer Case Overview Background Embedded Approach System Verification Results Summary GTx4, GTx5, GTx6

Test 2 Results Overview Background Embedded Approach System Verification Results Summary • 3 Dual Jammer Cases and 2 Triple Jammer cases at different locations • Performance Criteria • Reasonable (for Multi-Jammer Case) • Repeatable (for Multi-Jammer Case) For both dual and triple jammer scenarios

Test 3 • Synchronization of GPS and Jammer Signals • Requires a scenario utilizing GPS and Jammer Signals • Place one jammer sequentially in direction of each SV; allow AE to null • If all parts are working (receiver, AE, embedded jammer system) SV will be dropped Overview Background Embedded Approach System Verification Results Summary

Test 3 Set-up Overview Background Embedded Approach System Verification Results Summary Jammer laydown Satellite Constellation

Test 3 Results Overview Background Embedded Approach System Verification Results Summary • Performance Criteria • Reasonable

Summary • Embedded Jammer Approach Verified • Null depths/directions • Jammer/GPS signals in phase • Reasonable and repeatable results • Desire an upgrade to 7-box system • GAS-1 AE 7 element system • Utilize existing hardware • Complete verification after Software/Hardware Modifications Overview Background Embedded Approach System Verification Results Summary

7-Element Embedded Jammer Overview Background Embedded Approach System Verification Results Summary

Questions Overview Background Embedded Approach System Verification Results Summary

746TS Wavefront Simulator with Embedded Jammers