Improving the Horizontal Components Accuracy of Strapdown Airborne Vector Gravimetry by Yaw Continuous Rotation Modulation

Abstract

The accuracy of gravity disturbance horizontal components is an obstacle in strapdown airborne vector gravimetry at present. In the strapdown inertial navigation system (SINS) field, the rotation modulation technique has been put into practice to improve the accuracy of navigation for decades, which could suppress the divergence of SINS errors. Since there is a close connection between SINS and strapdown vector gravimetry, we were inspired to research on introducing rotation modulation into strapdown airborne vector gravimetry in this study. In this paper, the second section introduced the connections and differences between SINS and vector gravimetry. Then, the third section analyzed three main obstacles in improving the horizontal components accuracy of strapdown airborne vector gravimetry. To solve these problems, the fourth section proposed the mechanism of rotation modulation vector gravimetry from system level which is inspired by rotation modulation inertial navigation system (RMINS). On the basis of the mechanism, the fifth section designed a yaw continous rotation modulation scheme for vector gravimetry. Simulation and real-world static experiment demonstrated that the designed scheme has better performance in horizontal components than the classical strapdown gravimetry. Moreover, the experiment with drift showed that rotation modulation could also suppress the effects of the accelerometer long-term drift on gravimetry results. In conclusion, the paper introduced the rotation modulation into strapdown airborne vector gravimetry for the first time. It will probably provide a reference for developing the next generation strapdown airborne vector gravimeter.

An autonomous and high-accuracy gravity disturbance compensation scheme for rotary inertial navigation system

“…Combining equations ( 17) and ( 18), it can be seen that the nine components of the gravity disturbance gradient satisfy four constraints, so only five of these nine components are independent of each other. By substituting equations (17) and (18) into equation ( 16) and eliminating the dependent components of the gravity disturbance gradient, we can obtain…”

“…However, the application scope of this compensation method is restricted due to the complex manufacturing process, high cost and large volume of gravity gradiometer [4]. The fourth method obtains the measurement information of GNSS/INS integrated navigation system through high-accuracy differential GNSS, such as position, velocity and even acceleration, and then uses the optimal estimation algorithm to estimate and compensate the gravity disturbance and the other systematic errors [3,[16][17][18][19][20][21]. Although the accuracy of this method is high, its autonomy and reliability cannot be guaranteed because GNSS is vulnerable to interference and occlusion [22,23].…”

Autonomous ground vehicle gravity anomaly measurement and dynamic error compensation

“…When combined with high-precision SINS for integrated navigation, a synthesized velocity measurement accuracy of 0.05 m s −1 is achievable with a mileage constraint of 30 km. Assuming a latitude of 38 • N, v e = 12 m s −1 , v n = 5 m s −1 , a positioning error of 20 m, and a velocity error of 0.05 m s −1 , we can calculate the Eotvos correction error as less than 0.5 mGal according to the equation (2), which can also be acceptable. In order to minimize the impact of the vehicle horizontal acceleration, the measurement process should make every effort to keep the vehicle running at a constant speed and choose a good road condition with low traffic flow and a nearly straight measurement line.…”

“…All physical events on the earth and in its neighboring space are governed by gravity information, and all human productive life is inextricably linked to the gravitational field [1]. Accurate gravity anomaly measurements are critical for geodesy, resource exploration, weapon launch, and navigation [2]. Due to the irregular shape of the earth and its unequal mass * Author to whom any correspondence should be addressed.…”

Simulation Optimization and Application of Shearer Strapdown Inertial Navigation System Modulation Scheme

“…As the main sensor in the LASC system, the gyroscope was developed over a period of more than 170 years, and its accuracy means that it is difficult to achieve a big breakthrough [11,12]. As an error self-compensation method of INS, the essence of rotary modulation is to generate periodic attitude matrix changes through an external turning mechanism without improving the hardware level of the inertial sensor, thereby achieving self-compensation of the deterministic error of the inertial sensor [13,14] and improving the system accuracy for the long voyage. Scholars have been researching rotary navigation systems since the 1980s.…”