Error Source Analysis And Compensation In Test Chain For Dual-Axial Analog Sun Sensor

Based on 4-quadrant silicon cell, a dual-axial analog sun sensor can get the sun incident angle about two axes simultaneously. The acquisition accuracy of the four quadrant photocurrents determines the sensor performance directly. But the inconformity arisen from the test chain brings measurement deviation to the sensor. Therefore, based on numerical simulation, the influence model of the inconformity in the responsivity of each cell quadrant and then the C/V transformer, amplifier, A/D conversion and dark current for each quadrant photocurrent was established and analyzed. Then the calibration and compensation of such error sources were proposed. As a result, the requirement for the uniformity in the test chain can be lowered with the precondition of the sensor measurement accuracy. Test result shows that without changing the test chain parameters, the measuring accuracy of the sun sensor is improved from 2.05 degrees (alpha-axis, 3 sigma) and 1.94 degrees (beta-axis, 3 sigma) to 0.28 degrees (alpha-axis, 3 sigma) and 0.26 degrees (beta-axis, 3 sigma).