A Low-Cost MEMS Missile-Borne Compound Rotation Modulation Scheme

Abstract

Rotation modulation (RM) has been widely used in navigation systems to significantly improve the navigation accuracy of inertial navigation systems (INSs). However, the traditional single-axis rotation modulation cannot achieve the modulation of all the constant errors in the three directions; thus, it is not suitable for application in highly dynamic environments due to requirements for high precision in missiles. Aiming at the problems of error accumulation and divergence in the direction of rotation axis existing in the traditional single-axis rotation modulation, a novel rotation scheme is proposed. Firstly, the error propagation principle of the new rotation modulation scheme is analyzed. Secondly, the condition of realizing the error modulation with constant error is discussed. Finally, the original rotation modulation navigation algorithm is optimized for the new rotation modulation scheme. The experiment and simulation results show that the new rotation scheme can effectively modulate the error divergence of roll angle and improve the accuracy of roll angle by two orders of magnitude.

Optimal Rotational Angular Velocity Determination Method Based on Compound Rotary Semi-Strapdown Inertial Navigation System

“…There is no constant component of the gyroscope output error caused by the installation error, and the installation error is completely modulated. From the above analysis, it can be seen that, ideally, the modulation angular velocity condition that can satisfy the angular error δθ N caused by the installation error in a complete cycle without constant accumulation can be shown by Equation (22).…”

“…CRM changes the way that the IMU originally makes a single-axis rotation motion around the roll axis and rotates around the roll axis while rotating around the other axis perpendicular to the roll axis, so that the constant error in the direction of the unmodulated roll axis is also modulated. The navigation solution results show that the roll angle accuracy is improved by about 90%, and the position accuracy is improved by 70% [22]. In this context, it is required to complete the fast compensation of errors during the flight of shells with short flight time, such that traditional data processing methods such as Wiener filter and particle filter are not applicable due to their long update period [23][24][25].…”

An Improved Rotational Modulation Scheme for Tri-Axis Rotational Inertial Navigation System (RINS) with Fiber Optic Gyro (FOG)

“…RINS has a similar frame and rotation axis as the platform inertial navigation system, which can offset the constant and slowly-varying errors of the inertial measurement unit (IMU) and improve the navigation accuracy by about one order of magnitude [6][7][8][9]. RINS also has advantages in initial alignment [10,11] and self-calibration [12][13][14][15][16][17], which have drawn much attention recently [18][19][20][21]. Different kinds of single [22][23][24][25], dual [26][27][28], and tri-axis RINS [18,29,30] can be designed according to actual requirements.…”