The Advanced GPS Receiver project, sponsored by the Wright Laboratory at Wright-Patterson AFB, addressed the design of a highly jam-resistant GPS receiver. Under subcontract to Mayflower Communications Company, Integrity Systems (ISI) developed an integrated GPS code-tracking/navigation filter. This integrated filter was designed as a distributed (federated) filter. It employs ISI's information-sharing methodology to properly account for the common information passing from the GPS signal tracking loops to the GPS/inertial navigation filter, and from that filter back to the tracking loops via velocity aiding. The primary goal of this integrated filter design was to support enhanced anti-jam capability derived in part from wide variations in adaptive tracking-loop bandwidths.