A design study on complexity reduced multipath mitigation

Abstract. Global navigation satellite systems, e.g. the current GPS and the future European Galileo system, are frequently used in car navigation systems or smart phones to determine the position of a user. The calculation of the mobile position is based on the signal propagation times between the satellites and the mobile terminal. At least four time of arrival (TOA) measurements from four different satellites are required to resolve the position uniquely. Further, the satellites need to be line-of-sight to the receiver for exact position calculation. However, in an urban area, the direct path may be blocked and the resulting multipath propagation causes errors in the order of tens of meters for each measurement. and in the case of non-line-of-sight (NLOS), positive errors in the order of hundreds of meters.

In this paper an advanced algorithm for multipath mitigation known as CRMM is presented. CRMM features reduced algorithmic complexity and superior performance in comparison with other state of the art multipath mitigation algorithms. Simulation results demonstrate the significant improvements in position calculation in environments with severe multipath propagation. Nevertheless, in relation to traditional algorithms an increased effort is required for real-time signal processing due to the large amount of data, which has to be processed in parallel. Based on CRMM, we performed a comprehensive design study including a design space exploration for the tracking unit hardware part, and prototype implementation for hardware complexity estimation.