An error modulation scheme for a dual-axis rotational modulation inertial navigation system with limited transposition

Abstract Dual-axis rotational modulation has been recognized as a promising technique for suppressing inertial sensor errors, though its application in compact and mobile platforms remains limited due to challenges in system weight and reliability. This paper presents a novel 44-position dual-axis rotational modulation scheme that has the potential to enhance the reliability and reduces the weight of rotational inertial navigation systems by avoiding a full circle rotation in the vertical direction to reduce the use of slip ring structure, paving the way for their miniaturization and application in small and compact carriers. A theoretical analysis of IMU errors during the modulation process under the navigation frame is conducted based on the sensor coordinate system, and the modulation criterion under restricted rotation angle conditions is derived. Simulation and experimental results from a 24 hr navigation test using a 0.2 ∘ /h INS validate the scheme’s effectiveness to modulate IMU errors under one-axis rotation constraints. The results revealed a maximum horizontal position error reduction of 14.77 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="normal">%</mml:mi> </mml:mrow> </mml:math> compared to traditional methods, with an RMS error of 1.93 n miles.