A Trimble Advanced Navigation Sensor (TANS) Quadrex Global Positioning System (GPS) receiver processing unit and three antenna/preamplifier assemblies were flown aboard Space Shuttle Discovery, STS-51, as part of DTO 700-6, GPS On-orbit Demonstration (GOOD). The experiment was designed to quantify advantages and identify potential problem areas for Space Shuttle GPS operations using a low cost, commercial, space configured, GPS receiver. GPS data, including position, velocity, time, health, and status information were recorded during the mission. Following the mission, a reference trajectory was generated by NASA Johnson Space Center through post-processing of the Orbiter's on board navigation state. The recorded GPS data has been analyzed and compared to the reference trajectory to evaluate the navigational performance of the receiver. Additionally, postflight filtering of the GPS data has been performed in order to determine whether a significant increase in performance may be obtained through filtering.