Fig. 1. Fine tracking system of angle error detection based on local oscillator nutation using AOD

Fig. 2. Interference of oscillator beam and signal beam on the surface of detector when the two beams mismatch

Fig. 3. Heterodyne efficiency parameter γ as function of kr₀θ. Assuming that signal and local oscillator is plane wave

Fig. 4. Operation principle of Bragg grating

Fig. 5. Diagram of angle between local oscillator and signal

Fig. 6. (a) Calculation of azimuth of signal angle error; (b) calculation of quantity of signal angle error; (c) calculation error of azimuth of signal angle error; (d) calculation error of quantity of signal angle error

Fig. 7. Light path diagram of the system

Fig. 8. Measurement of heterodyne efficiency curve. (a) Envelope of detector voltage signal; (b) control voltage of FSM; (c) comparison of theoretical and measured normalized heterodyne efficiency

Fig. 9. (a) Driven signal of horizontal AOD; (b) driven signal of vertical AOD; (c) nutation angle of local oscillator

Fig. 10. Comparison of measured angle error and actual error. (a) Voltage signal of detector; (b) comparison of the measured and actual error of angle; (c) measurement error