Compared to conventional hardware GPS receivers (GPSR), software GPS receivers are more suitable for research and development. Software GPS receivers can be dynamically programmed in software to reconfigure the characteristics of GPS receiver and new algorithms can easily be integrated without changing the design of the hardware. However, the most important issue for this approach is the computational load. It can be solved by using the high performance state-of-art digital signal processor. The harshness of space environment, such as Total Ionizing Dosage (TID), Single Event Effect (SEE), always cast certain thread to GPS receiver intended for space applications. Common resolution to cope with this thread is the robustness of space grade EEE parts toward those effects along with the protection of circuit design. Nevertheless, the most of the state-of-art EEE parts are not space qualified. In this study, certain Commercial Off The Shelf (COTS) parts such as COTS level RF Front-End (RFFE) and Digital Signal Processor (DSP) along with single event effect (SEE) mitigation circuit design, are considered in the proposed GPSR design for their advantages, such as availability, performance, size, weight and lead time, over regular space qualified ones.