INS/GPS/pseudolite' integrated navigation for land vehicle in urban canyon environments

The vehicle navigation and location system plays an essential role in all aspects of ITS. GPS/INS integrated navigation system has been widely used in land vehicle navigation. However, the performance of INS/GPS integrated system will severely degrade in urban canyon environments, where the GPS signals are often blocked by high-rise buildings, dense foliage and tunnels. To solve the problem, a pseudolite-augmented scheme is proposed, and a modified measurement model is presented, which uses the double difference of measured pseudo-ranges and INS estimated ranges. By employing this scheme, only two GPS signals are required to position a fix if using one pseudolite, which can be satisfied in,many urban canyon environments. Simulation results indicate that this approach can solve the urban canyon problem successfully.