Improving Strapdown Airborne Gravimetry by Yaw Tracking Rotation Modulation

Strapdown airborne gravimetry is a classical method to obtain the high quality gravity disturbance information. However, the horizontal components of the strapdown vector gravimetry are still potential for improvement. Residual error in navigation frame, originated from attitude error and accelerometer bias, is the main factor affecting the accuracy of the vector gravimetry. Theoretical analysis and actual repeat line data show that the variation of the flight direction would change the sign of the residual error, and this will create biases in the results of the survey lines in different direction. Therefore, keeping the yaw angle unchanged could eliminate the effect of residual error in strapdown gravimetry; this could be achieved by single axis rotation modulation. In this paper, strapdown vector gravimetry with yaw tracking rotation modulation technique is proposed to conquer the effect of residual bias. Simulation results show that the errors of horizontal gravity disturbance are reduced from 3.45 mGal and 4.59 mGal to 2.48 mGal and 1.77 mGal after using the improved gravimetry scheme.