A Feasibility Study on L1/L2C Software RSIM for Maritime DGPS

Abstract

Commercially available hardware dedicated off-the-shelf maritime differential GPS RSIM lacks the open architecture to meet all the minimum maritime user requirements and to include future GNSS improvements. This paper carries out a feasibility study to replace existing hardware dedicated differential GPS RSIM with software differential GPS RSIM in order to make up the weak point of hardware dedicated off-the-shelf maritime differential GPS RSIM. In this paper, the architecture of software RSIM is proposed for maritime DGPS. And the feasibility analysis of L1/L2C dual frequency software differential GPS RSIM is performed as the first phase to realize the proposed architecture. For the feasibility analysis, the prototype RF/IF module and DSP module are implemented with properties as wide RF bandwidth, high sampling frequency, and high speed transmission interface. This paper shows that the proposed architecture has the possibility of real time operation of software RSIM functionality onto the PC-based platform through the analysis of computation load. Finally, this paper verifies that the L1/L2C dual frequency software differential RSIM designed according to the proposed architecture satisfies the performance specifications set out in RTCM paper 221-2006.