Application of Street Tracking Algorithm in an INS/GPS Integrated Navigation System

Most inertial navigation system/global positioning system (INS/GPS) navigation systems for vehicles estimate position, velocity, and heading information from the GPS, and dead reckoning such as INS using a Kalman filter. However, it may suffer from INS noise, GPS noise and, especially, GPS outage. Map-matching is an additional facility to reduce errors caused by GPS outage. Usually, it has to trade-off between the performance and the complexity. In this paper, we have proposed a new map-matching algorithm called street tracking algorithm (STA) to not only correct the position error, but also estimate the velocity and the heading of the navigation system. When the GPS signal is lost, the Kalman filter is put in prediction mode and the STA is enabled. The raw acceleration of inertial measurement unit measured in body frame is also brought directly to STA as an input. The experimental result has shown that when GPS signal is lost, we can control the position error at around 2.5 m, and the velocity error at around 3.2 m/s. The proposed map-matching algorithm STA can be applied in various kinds of environment due to its simplicity and flexibility.