Performance Test Results of an Integrated GPS/MEMS Inertial Navigation Package

This paper describes the design, operation and performance test results of a miniature, low cost integrated GPS/inertial navigation system (INS) designed for use in UAV or UGV guidance systems. The system integrates a miniaturized commercial GPS with a low grade Micro-Electro-Mechanical (MEMS) inertial measurement unit (IMU). The MEMS IMU is a small self-contained package (< 1 cu inch) and includes a triad of accelerometers and gyroscopes with additional sensors integrated for temperature compensation and baro pressure altitude aiding. The raw IMU data is provided through a serial interface to a processor board where the inertial navigation solution and integrated GPS/inertial Kalman filter is generated. The GPS/Inertial software integration is performed using NAVSYS’ modular InterNav software product. This allows integration with different low cost GPS chips sets or receivers and also allows the integrated GPS/inertial navigation solution to be embedded as an application on a customer’s host computer. This modular, object oriented architecture facilitates integration of the miniature MEMS GPS/INS navigation system for embedded navigation applications. Test results are presented in this paper showing the performance of the integrated MEMS GPS/INS navigation system when used to perform guidance for a small Unmanned Ground Vehicle (UGV). Data is provided showing the position, velocity and attitude accuracy when operating with GPS aiding and also for periods where GPS dropouts occur and alternative navigation update sources are used to bound the MEMS inertial navigation error growth.