A method for estimating and compensating for angle cross-range bias in differential wavefront sensing

Abstract

This invention relates to the field of differential wavefront sensing angle technology, and particularly to a method for estimating and compensating for lateral offset in differential wavefront sensing angles. The method includes: independently modulating the reference beam and the measurement beam with sinusoidal intensity, enabling the two beams to carry different frequency signatures, thus achieving power decoupling in the interference signals; incident on a four-quadrant photodetector and interfering, acquiring and processing the interference electrical signals to obtain four digital test signals; executing three independent signal processing branches in parallel on the four digital test signals to calculate the lateral offset of the reference beam and the measurement beam, as well as the pitch and yaw angle observations including pseudo-differential phase errors; constructing pseudo-differential phase components, and subtracting these components from the pitch and yaw angle observations in real time to compensate for and suppress lateral offset errors. The advantages are: real-time extraction of the amplitude of the two interferometric beams based on intensity modulation and estimation of lateral offset, effectively suppressing errors and improving angle measurement accuracy.

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