The overall objective of the HSGR Program is to develop a high sensitivity military GPS receiver to provide reliable GPS navigation, under weak GPS signal conditions, to ground based military GPS users. Mayflower’s approach to meet this HSGR program objective is to design, develop and incorporate “high-sensitivity” signal processing enhancements (namely, Vector Tracking (VT) and Multi-bit GPS correlation) in the Mayflower NavAssure™ GPS receiver. This will result in a HSGR receiver that will provide significant improvement in signal tracking performance over conventional military GPS receivers. These enhancements will be implemented with software-only upgrades to the Mayflower NavAssure™ receiver. In the Phase II of this NGA HSGR SBIR program, Mayflower proposes to refine the algorithms developed in Phase I and demonstrate the benefits of the enhancements on a prototype hardware platform in a laboratory as well as in an outdoor environment, representing the weak signal conditions a GPS receiver is subjected to in an urban environment.