Single Step Ultratight GPS Acquisition to Navigation

Significant GPS anti-jam performance improvements for GPS-guided weapons can be achieved through the use of Ultra-Tightly-Coupled (UTC) GPS/inertial integrated systems. However, current UTC processing techniques use conventional code and carrier trackingloops to transition from direct signal acquisition to the UTC mode. This diminishes the benefits that can be achieved by UTC tracking in a jamming environment.Under this proposed SBIR effort, we will develop a high A/J direct P(Y) code acquisition mode for UTC signal processing. Our proposed approach, termed UTC-ACQ , uses an innovative hypothesis test algorithm to search the position uncertainty space for theset of visible GPS satellite signals. An atomic clock is used to limit the time uncertainty. This approach significantly improves the A/J acquisition margin by leveraging the UTC processing to use the combined set of satellite signals for acquisition forimproved A/J protection.Under Phase I, we will implement the UTC-ACQ algorithm and test its performance for direct P(Y) UTC acquisition under simulated jamming conditions. A design will be presented for a UTC GPS/inertial prototype system to be implemented and tested under thePhase II effort. The NAVSYS UTC Software GPS Receiver will allow high flying reconnaissance aircraft operate in severe jamming environments to provide target detection and precision location that our warfighters need to accomplish their missions with the lowest riskpossible. The U2, Global Hawk, BAMS, AWACS and other similar sircraft will be the first platforms to commercialize the innovations to be developed by this effort.