SiCOM proposes to develop a small, low-power, and low-cost device to enable operation of GPS receivers in strong interference and jamming environments. The device will enable GPS receivers, including upgrades to the Military Airborne GPS Receiver (MAGR), and the Army's family of handheld GPS receivers, to operate with partial-band jamming signals 1000 times stronger than otherwise possible with existing military GPS radios. SiCOM proposes to produce the device as a single integrated circuit chip less than 0.3 inch on a side, consuming less than 0.2 watt. The device will perform spectral excision of offending signals using an innovative fast Fourier transform (FFT) algorithm that enables excision without distorting the satellite signals. SiCOM calls this processing "AJAX" (Anti-Jam Adaptive eXcision). Phase I of the proposed project will: 1) determine the feasibility of integrating AJAX processing and an analog-to-digital converter in a single small-size, low-power application-specific integrated circuit (ASIC), 2) determine the feasibility of integrating other GPS processing functions, such as de-spreading of GPS signals in the same ASIC, thereby saving additional size, power, and cost of GPS receivers, 3) optimize design features such as word length and automatic gain control, and 4) demonstrate AJAX performance using a modified military GPS receiver.
