Low Cost Precise Navigation in Urban Area with Multi-Constellation GNSS and Inertial-Aiding

Abstract : Positioning with stand-alone GPS is known to be strongly degraded in a constrained environment (urban or sub-urban conditions) due to frequent signal masking, strong multipath effect, frequent cycle slips on carrier phase, etc. The objectives of this work is to explore the possibility of achieving precise positioning with a low-cost architecture: a low-cost GNSS mono-frequency receiver and MEMS. The following aspects are considered to improve the PVT performance: consideration of multi-GNSS constellations (GPS+GLONASS), inclusion of carrier phase measurements, the RTK methodology and MEMS to restrict the degradation during GNSS outages. To detect cycle slips, a specific detector scheme is used which is also capable of detecting CS on the reference station-side. Besides, to bring the high-accuracy carrier phase measurements to absolute measurements, their integer ambiguities are fixed by using a modified version of Partial Ambiguity Resolution (PAR).