Design, capabilities and performance of a miniaturized airborne GPS receiver for space applications

A GPS receiver for NASA´s Space Shuttle GPS development Flight Test (DFT) Program has been developed by the Collins Avionics & Communications Division (CACD), Rockwell International. This development receiver-a prototype-subsequently is referred to as the DFT unit. It is a hybrid of hardware from Rockwell´s 3M receiver and software from the DoD standard miniaturized airborne GPS receiver (MAGR), also built by Rockwell´s CACD division. The only modifications to the receiver´s hardware baseline were those required to accommodate a serial data interface that is unique to the Space Shuttle, and to accommodate an inertial aiding format. Modifications to the MAGR software baseline were also made to extend the GPS receiver´s capabilities to address performance requirements peculiar to low Earth orbit space flight. Accommodating higher range rates and more rapid changes in satellite visibility were among the additional requirements