Analysis on effecting mode of several essential factors to gravity aided navigation

The effect of sample length,sampling interval and gravity measurement error on the gravity aided navigation is systematically analyzed based on modified TERCOM(terrain contour matching) arithmetic.The quasi-real-time simulation shows that:(1) The sample length has much influence on the matching result,too long or too short can neither match to the optical grid point.Experiments show that the matching result is good when the ratio of sampling length to the base map resolution is between 10 and 20;(2) Increasing the sampling interval can improve the matching precision when sample length is fixed.However the risk of matching error increases at the same time.The sampling interval is chosen to be 2 min to 4 min is recommended;(3) The white noise error of gravity measurement has much influence on the matching,and too much measurement error coould induce invalid matching.Measurement error within 2 mGal is recommended.