Implementation of Effective Scale Factor Matching and Axial Centripetal Error Compensation for a Rotating Accelerometer Gravity Gradiometer

Abstract

Rotating accelerometer gravity gradiometer (RAGG) is the only gravity gradient measuring device in the world to achieve commercial applications. When the parameter consistency among multiple accelerometers of the RAGG is not sufficient, its combined output cannot effectively suppress common-mode noise in the environment. A method for suppressing RAGG’s linear and angular motion noise is presented in this article by projecting the parameters, including scale factor, misalignment angle, second-order terms, and cross-coupling terms, onto the Cartesian coordinate system of the turntable plane. Proposing the algorithm implementation scheme of three effective scale factor solver loops, and for further canceling the motion residual error, high-precision gyroscope compensation loops are introduced. The added error compensation loop obtains the angular acceleration by differencing the angular velocity measured by the gyroscope, which in turn adjusts the loop parameters. Experimental results show that with the proposed method, the noise suppression of linear motion common-mode acceleration reaches 6.5 orders of magnitude, that is, the noise level <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.7 \times {10^{ - 8}} {\mathrm{ g/}}\sqrt {{\mathrm{Hz}}} $ </tex-math></inline-formula> of the accelerometer at the rotation frequency, and the angular motion common-mode acceleration noise is suppressed by six orders of magnitude, and the noise level <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$6.8 \times {10^{ - 8}} {\mathrm{ g/}}\sqrt {{\mathrm{Hz}}} $ </tex-math></inline-formula> of the accelerometer at the swing frequency is also obtained.