Observability Analysis of a MEMS INS/GPS Integration System with Gyroscope G-Sensitivity Errors

Abstract

Gyroscopes based on micro-electromechanical system (MEMS) technology suffer in high-dynamic applications due to obvious g-sensitivity errors. These errors can induce large biases in the gyroscope, which can directly affect the accuracy of attitude estimation in the integration of the inertial navigation system (INS) and the Global Positioning System (GPS). The observability determines the existence of solutions for compensating them. In this paper, we investigate the observability of the INS/GPS system with consideration of the g-sensitivity errors. In terms of two types of g-sensitivity coefficients matrix, we add them as estimated states to the Kalman filter and analyze the observability of three or nine elements of the coefficient matrix respectively. A global observable condition of the system is presented and validated. Experimental results indicate that all the estimated states, which include position, velocity, attitude, gyro and accelerometer bias, and g-sensitivity coefficients, could be made observable by maneuvering based on the conditions. Compared with the integration system without compensation for the g-sensitivity errors, the attitude accuracy is raised obviously.

External Disturbances Rejection by Differential Single-Mass Vibratory Gyroscope

“…Figure 5 shows responses of three channels (X, Y and differential ones) of differential CVG under 5 shocks along IA. As can be seen from the peak response values indicated on the figure 5 rejection factor, calculated by (5), is close to Rsp=2.…”

“…Figure 8 shows change in biases after each of five of 20 g shocks along gyro IA. Shock rejection factor in terms of bias change can be calculated using (5), where Xi and Yi are change of biases of corresponding channels before and after i-th shock. Average over 5 shocks change of absolute value of biases is 0.0097 deg/s for differential channel and for minimum of X and Y channels it is 0.03 deg/s, hence, Rsb=0.03/0.0097≈3.…”

“…Angle errors during 100g shocks along IA Shock rejection factor in terms of bias change and differential CVG bias sensitivity to shock acceleration along IA can be calculated, according to (5) and (6), respectively, from the data presented in Figure 11. Figure 12 shows X, Y and differential channel responses to 5 lateral shocks of 20 g amplitude and 2 ms duration.…”

Novel In-flight Coarse Alignment of Low-cost Strapdown Inertial Navigation System for Unmanned Aerial Vehicle Applications

“…1,2016 estimation accuracy and accelerate the initial alignment process. 1,21,22) In the following subsection, the flight experiment is discussed and analyzed. The coarse alignment results are compared with a corresponding reference (i.e., RTK/MIMU integrated navigation results) to evaluate the performance of the proposed algorithm.…”

Local Observability Analysis of Star Sensor Installation Errors in a SINS/CNS Integration System for Near-Earth Flight Vehicles

“…The concept of local observability and locally observable assertion is introduced in [16,17]. For near-Earth flight vehicles, star sensors could be frequently allowed to use shorter measurement intervals [18]. Moreover, a locally observable system is sure to be globally observable, while a globally observable system is not sure to be locally observable [2].…”