SBIR-STTR Award

Vector waveform estimation theory implies that a GPS signal processor be constructed as a centralized estimator, in which inter-path statistical information is utilized in extracting state dynamics information from the spread spectrum signals. TISI has developed and implemented such a scheme, known as Integrated Demodulation Navigation (IDN), which addresses robust carrier phase tracking in high Dynamics and blockage. In extending this development to the tactical jamming environment, specific challenges must be surmounted including estimation of signal amplitudes and compensation for deleterious amplitude and phase effects introduced by front-end spatial nulling. In its Phase I effort an enhanced amplitude estimation scheme for IDN will be developed, which will be evaluated in non-linear tracking simulations. TISI's simulator environment will be extended to include antenna pattern and vehicle blockage effects, as well as multiple jammer sources. A simplified model of spatial nulling disturbances will also be introduced. In preparation for RF testing of a prototype receiver in Phase II, MacAulay-Brown will develop a virtual GPS receiver environment concept for capture and playback of actual jammer and spatial pre-filtering scenarios produced by the AWFS. Finally, TISI will identify and compare options for implementing IDN in the GRAM-SAASM framework.

Vecter waveform estimation theory implies that a GPS signal processor be constucted as a centralized estimator, in which inter-path statistical information is utilized in extracting state dynamics information from the spread spectrum signals. TISI's Advanced GPS Receiver (TAGR) is a 12-channel C/A code realization of this Integrated Demodulation/Navigation (IDN) technology. Signal amplitude estimation and antenna spatial nulling compensation must be addressed in applying this technique in jamming.In Phase I TISI's IDN filter technology was adapted to the A/J environment. Algorithms developed included correlator-level fault detection and identification (FDI), amplitude estimator aiding(AEA), and cooperative nuller aiding (CNA). In these studies TISI extended its TrackView simulator to include multiple jamming sources, antenna phase and gain data collected with the AWFS. TISI developed an approach for interfacing its filter processor directly to a proven GRAM-SAASM receiver board, in preparation for receiver prototype TAGR-M. Under sub-contract, Software Technologies and Systems (STS) will support the prototype effort. Interface testing and filter verification will be carried out with a real-time version of TrackView. To facilitate prototype RF testing, TISI and MacAulay-Brown developed a digital recording concept, VGRE, for capture and playback of the complex AWFS RF environments. Critical digital companding and AGC elements of VGRE will be built and tested early in Phase II, prior to full development/deployment of VGRE under a Phase II Option.

Keywords:
GPSJAMMING IMU AIDING GRAAM-SAASM SPATIAL NULLING VIRTUAL JAMMING ENVIRONMENT CARRIER TRACKING