Electronic noise analysis and in-orbit resolution verification of an electrostatic accelerometer

Based on the working principle of the signal detection and servo feedback control of the electrostatic accelerometer, in this paper, the main electronic noise components affecting the measurements of the accelerometer are analyzed and the corresponding expressions are determined. The resolution of the designed electrostatic accelerometer is lower than 10[Formula: see text]m/s2/Hz[Formula: see text], which cannot be verified directly due to limitations imposed by the vibration of the ground environment. However, it can be evaluated indirectly by the testing of electronic noise under open-loop conditions. Through this process, the resolution of 3× 10[Formula: see text]m/s2/Hz[Formula: see text] of the Taiji-1 inertial sensor was verified and found to be in agreement with results obtained in orbit.

Future Electrostatic Accelerometer without Polarization Wire

<p>ONERA (the French Aerospace Lab) is developing, manufacturing and testing ultra-sensitive electrostatic accelerometer for space application. Accelerometers have been successfully developed for the Earth-orbiting gravity missions CHAMP, GRACE, GOCE and GRACE-FO and for Earth-orbiting Fundamental Physics mission MICROSCOPE.</p><p>In ONERA accelerometer design, the proof mass was levitated and was maintained at the center of an electrode cage by electrostatic forces. Moreover this proof mass was connected by a thin conductive wire (typically 5, 7 or 10 µm diameter wire). This wire allows us to polarize the proof mass and to evacuate the random charges induced by space radiation.</p><p>By removing this polarization wire, there will be positive impacts on the accelerometer defaults such as the removal of the parasitic dumping noise at low frequencies created by wire or its bias contribution; but it is important to verify that there are not also negative impacts such as noisy charging process.</p><p>After studying the evolution of the space radiation energy distribution on interesting orbits for earth missions, an evaluation of implemented current on the proof mass has been performed. A UV LED had been tested; the set-up and first measurements will be presented. Moreover a prototype is developed by ONERA to characterized charge management capabilities of such a system on a representative environment.</p>

ONERA accelerometers for future gravity mission

<p>ONERA (the French Aerospace Lab) is developing, manufacturing and testing ultra-sensitive electrostatic accelerometer for space application. ONERA has procured the accelerometer for all the previous gravity missions (GRACE, GOCE, GRACE-FO) and works to improve the scientific return of the instruments.</p><p>One way is to propose an accelerometer with 3 sensitive linear acceleration measurements as well as 3 angular acceleration measurements for the attitude control or reconstruction. Two different configurations are proposed: CubSTAR, a miniaturized version with low accuracy but adapted for constellation or nanosat; and MicroSTAR, a high accuracy accelerometer.</p><p>CubSTAR accelerometer is a small volume instrument with the same performance on the 3 axes, the baseline being 20x20x20mm proof-mass in a 15x15x20cm volume envelope. A prototype was manufactured and tested during a drop-tower test. Moreover this prototype will be tested in vibration environment to check its good mechanical behavior.</p><p>MicroSTAR accelerometer is designed with a disruptive mechanical concept allowing using a 30x30x30mm proof-mass, with the same high-performance on the 3 axes. Modal and dynamic analyses have been performed and a prototype is under manufacturing.  </p>