Investigation of Multipath Mitigation Methods for High Precision GNSS Applications

The measurements accuracy in Global Navigation Satellite Systems (GNSS) is limited by multipath propagation. Consequently, multipath mitigation techniques are essential for high precision GNSS applications utilizing pseudorange observations. Narrow correlator (Fenton & Van Dierendonck 1995) and gated and high resolution correlator (McGraw & Braasch 1999) are introduced to reduce the multipath error in pseudorange measurements. In Sleewaegen (1997) a method based on signal amplitude information was utilized to reduce the multipath error on pseudorange measurement. These correlator-based multipath mitigation techniques have been used extensively in most high grade GNSS receivers; however, these techniques are mostly patent protected. Recently, an approach based on combination of squared correlators (CSC) similar to the structure of the double delta correlators are introduces for safety-of-life application. In this paper, a new GNSS receiver correlator architecture is implemented in a FPGA based compact platform which results in reduction of multipath error. Experimental measurements compare the performance of different code discriminators considering the proposed correlator configuration. The performance of the proposed method is evaluated in the measurement and positioning levels.