Accuracy improvement of low-cost INS/GPS for land applications.

摘要

Since the usage of high performance inertial navigation systems (INSs) is limited by their high price and the regulation by the government, low cost INSs are used for general application areas. However, low cost INSs can experience large positioning errors in very short time due to the low quality of the inertial measuring unit (IMU). To overcome the limitations of low cost INSs, several techniques were developed and tested using the NovAtel Black Diamond System (BDS™).; A new field calibration method was developed and tested successfully. It is not needed to align the IMU to the local level frame with the method. Furthermore, the bias estimation of the calibration method is not affected by the reference gravity error. Almost half of the positioning error could be removed with the accelerometer calibration information.; The mechanization and navigation Kalman filter were implemented based on the navigation frame to test the velocity matching alignment and non-holonomic constraints. The velocity snatching alignment technique was tested for the IMUs to which stationary alignment technique cannot be applied. All attitude components converged within three minutes with RMS 0.03°. Non-holonomic constraints dramatically reduced the horizontal positioning error, within 40 m for 20 minutes operation. Therefore, low cost INSs can be used as a stand-alone positioning system during the GPS outages of over 10 minutes.