A fully software Global Navigation Satellite System (GNSS) receiver implementation holds many advantages over traditional receiver designs. The most significant of these advantages is the tremendous flexibility in the signal processing. One of the difficulties associated with a software radio implementation is programmable processing power required. Typically a chip specifically design for a single task, such as an application specific circuit (ASIC) can provide much higher throughput for the specific task it is hardwired to perform. However with the currently technology a fully functional multi-channel real time GPS receiver is feasible. This has been proven with a PC platform as well as in a DSP implementation. In the first part of the PC implementations is described. The main focus of this paper is an application of the software radio critical for developers of GNSS (current GPS and future Galileo) receivers - the evaluation of various front end ASICs for use in GNSS receivers. Is has been relatively easy to compare different GPS receiver architectures. However, for those developers looking to use individual components, consider the front end ASIC individually as an example, it is quite difficult to quantify the performance of various commercial versions available using traditional receivers. This not the case with software radio since the software architecture is independent of the front end design. Results of testing four different front ends are reported within the paper.