Research Of Mimu/gps/magetometer Integrated Navigation Technology

Since the 1990s, high and new technology weapons have been more and more widely used and play very important role in wars .The high precision of high and new technology weapons has became an inevitable trend in the futrue. As the demand of navigation devices in military grows continuously, the low-cost request of navigation systems are becoming higher and higher.The MIMU/GPS integrated navigation system uses the advantages of GPS and MIMU to complement each other. It's a kind of ideal integration. But to the low-cost MIMU sensors and GPS receiver, the problem of poor observability in heading error exists in the MIMU/GPS integration. The heading error diverges when the acceleration of the carrier is zero or some small value. By the help of the magnetometer in independence and all-weather service, the addition of magnetometer sensor overcomes the shortcoming of MIMU/GPS integration. For the above reasons, researches on the following aspects of the low-cost MIMU/GPS/magnetometer have been done in this paper:1. The filter model of MIMU/GPS/magnetometer integrated system were derived. The performance of integrated system was analyzed by the observability analysis and heading error analysis. The observability analysis showed that the heading error can be observed in any cases when magnetometer were added into the integrated system, and the shortcomeing of MIMU/GPS integrated system in some special moving conditions were overcomed. The heading error analysis showed that the heading error was less than 1°in our own territory, while the level attitude error was less than 0.5°and the roll angle was less than 10°without consideration of measure error of magnetometer.2. An online magnetic deviation calibration method based on recursive least square algorithm was presented. Based on the conclusion of traditional magnetic deviation calibration method, the limitation of the traditional method on the engineering application was analyzed and the new method was presented. Experiments were done to verify the new method.The results showed that online magnetic deviation calibration can be done by the new method and the validity of the method was proved through the magnetic deviation calibration of system online.3. The performance of integrated navigation system were verified by simulations and vehicle experiments. The simulation based on Simulink showed that after adding magnetometer into the MIMU/GPS integration, the problem that the heading error of original integration diverges when the acceleration of carrier is zero or small value is solved. In any cases, the position, velocity and attitude error of the system converges efficiently. The static experiment and vehicle experiment were done after choosing the low-cost sensors as experimental devices. The static experiment showed that the level attitude error converges the same as the MIMU/GPS integrated system while adding the magnetometer into it. But the heading error turned from divergence into converge after the adding. The vehicle experiment also showed that adding suitable algorithm into the MIMU/GPS/magnetometer integrated navigation system and, doing the magnetic deviation calibration before running the system, all the kinds of error keeps in small values when the system was running.