Space-borne laser range finder echo detection circuit

Abstract

The invention discloses a satellite-borne laser range finder echo detection circuit, and the circuit comprises a power filtering circuit, an APD detector (module), a differential amplifier circuit, a passive Bessel filter circuit, and a transformer isolation circuit. The power filtering circuit carries out the filtering of an input power supply, so as to meet the requirements of each unit of the detection circuit for power ripples and noise. The APD detector (module) is a photoelectric device which achieves the laser echo detection, obtains an internal gain under the condition of external high-voltage bias, and achieves the detection of a weak signal. The differential amplifier circuit is used for converting a single-end current (voltage) signal outputted by the APD detector (module) into a differential signal, and improves the anti-interference capability of signal transmission. The passive Bessel filter circuit enables the signal bandwidth to be limited in a proper frequency band range under the condition of guaranteeing no signal distortion, so as to obtain the optimal SNR and meet the demands of different applications.

Description

technical field [0001] The invention relates to an echo detection circuit based on an APD detector (module) for a spaceborne laser range finder. Background technique [0002] The spaceborne laser rangefinder generally works in an orbit of hundreds of kilometers, and the laser emission power of several MW is passed through R 2 After the distance attenuation and atmospheric two-way attenuation, the laser echo optical power is generally only on the order of tens of nW. How to effectively detect and extract such a weak laser echo signal is the key to the laser ranging system. The avalanche photodiode (APD) has high quantum efficiency, extremely high sensitivity and extremely short response time, and has become the first choice for the detection of weak signals of spaceborne laser distance meters. At present, the general design method of the echo detection circuit of the spaceborne laser range finder is to output the output signal of the APD detection module directly through the...

AI Technical Summary

Problems solved by technology

At present, the general design method of the echo detection circuit of the spaceborne laser range finder is to output the output signal of the APD detection module directly through the coaxial cable or to output the current signal output by the APD detector through the coaxial cable after I / V conversion. Only the APD detection circuit is included in this circuit. The disadvantage of this circuit is that the signal-to-noise ratio of the nW-level echo signal is extremely low after photoelectric conversion by the APD detection circuit, and the signal quality of the single-ended non-isolated transmission mode is easily affected by the external environment. Especially the impact of the space environment, resulting in further deterioration of the signal-to-noise ratio or signal distortion, which is not conducive to back-end signal detection and affects the ranging accuracy

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