An optical beam tracking method comprising: receiving, at signal processing hardware , axis signals from a multi-axis position sensing detector , each axis signal indicative of a beam position of an optical beam incident on the multi-axis position sensing detector , each axis signal corresponding to an axis of the multi-axis position sensing detector ; generating, by the signal processing hardware , a reference signal by summing the axis signals ; for each axis of the multi-axis position sensing detector : converting, by the signal processing hardware , a phase of a first axis signal of the axis to have a 90 degree phase difference from a second axis signal of the axis ; generating, by the signal processing hardware , an axis-phasor signal by summing the first and second axis signals , the axis-phasor signal having an angle that maps to the beam position of the optical beam; comparing, by the signal processing hardware , the axis-phasor signal and the reference signal to determine a phase difference, the phase difference mapping to a beam position error along the corresponding axis on the multi-axis position sensing detector ; and determining, by the signal processing hardware , a mirror position of a mirror directing the optical beam based on the beam position error of each axis of the multi-axis position sensing detector ; and actuating, by the signal processing hardware , the mirror to move to the mirror position. receiving, at signal processing hardware , axis signals from a multi-axis position sensing detector , each axis signal indicative of a beam position of an optical beam incident on the multi-axis position sensing detector , each axis signal corresponding to an axis of the multi-axis position sensing detector ; generating, by the signal processing hardware , a reference signal by summing the axis signals ; for each axis of the multi-axis position sensing detector : converting, by the signal processing hardware , a phase of a first axis signal of the axis to have a 90 degree phase difference from a second axis signal of the axis ; generating, by the signal processing hardware , an axis-phasor signal by summing the first and second axis signals , the axis-phasor signal having an angle that maps to the beam position of the optical beam; comparing, by the signal processing hardware , the axis-phasor signal and the reference signal to determine a phase difference, the phase difference mapping to a beam position error along the corresponding axis on the multi-axis position sensing detector ; and converting, by the signal processing hardware , a phase of a first axis signal of the axis to have a 90 degree phase difference from a second axis signal of the axis ; generating, by the signal processing hardware , an axis-phasor signal by summing the first and second axis signals , the axis-phasor signal having an angle that maps to the beam position of the optical beam; comparing, by the signal processing hardware , the axis-phasor signal and the reference signal to determine a phase difference, the phase difference mapping to a beam position error along the corresponding axis on the multi-axis position sensing detector ; and determining, by the signal processing hardware , a mirror position of a mirror directing the optical beam based on the beam position error of each axis of the multi-axis position sensing detector ; and actuating, by the signal processing hardware , the mirror to move to the mirror position. <EOS>