Gravity disturbance has become a major error source in high-precision inertial navigation systems,and compensating it can further improve navigation accuracy.The EIGEN-6C4 gravity field model can calculate gravity disturbances on a global scale.The higher the model order is,the more accurate the calculation results are,however,the corresponding computational and storage costs become larger,and it is difficult to meet real-time requirements by using high-order models on traditional navigation computers,while using low-order models can lead to significant truncation errors.In response to the above issues,based on the relationship between model order and spatial resolution,as well as the propagation characteristics of gravity disturbances in inertial navigation mechanics arrangement,a real-time gravity compensation scheme that can be easily im-plemented in embedded systems and can be reduced in frequency and order with the motion state of the carrier is studied.The software and hardware solutions are implemented using DSP,and final-ly,the real-time performance and required compensation accuracy of the scheme are verified through semi-physical simulation,the maximum improvement of position accuracy in the east and north directions is 649 m and 686 m respectively,and the average improvement effect is 94％of the magnitude of the accuracy improvement after compensating the 2 190-order gravity model.
Real-time gravity compensationEIGEN-6C4 gravity field modelInertial navigation systemEmbedded system
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