APD偏压的环境自适应数字控制技术研究

Digital Controlling Technology Research of APD Bias Voltage Self-Adaptation to Environment

激光测距接收系统中,雪崩二极管偏压与增益密切相关,从而最终影响其测距能力。通过设计偏压自适应数字控制平台,以单片机作为偏压控制单元,DSP作为信号处理单元,可根据环境温度以及测距目标信号和噪声的幅度对APD的偏压进行实时调整,实现APD偏压对测试环境的自适应功能。实验表明,APD偏压自适应平台对不同环境温度、光照强度和能见度等环境条件均具有较好的适应性,不仅可以较好地控制激光测距仪的虚警率(测试过程中无虚警),而且可以提升其在强光照以及不同能见度条件下的信噪比,强光照时信噪比提升了0.48dB,能见度为8km时信噪比提升了1.68dB,能见度为5km时信噪比提升了0.88dB,能见度为3km时信噪比提升了0.02dB。

Aiming at the important influence of the APD bias voltage in the laser rangefinder receiving system,a digital signal controlling platform is designed,which is based on MCU as bias voltage controlling unit and DSP as signal processing unit.The function of self-adaptation to environment is realized by adjusting the APD bias voltage according to the environment temperature and noise level of the target.The result shows that this platform has good applicability in different temperature,light intensity and visibility,which not only reduces the false alarm of laser rangefinder（no false alarm during the test）,but also increases the SNR.The SNR is increased 0.48 dB in strong illumination.The SNR is increased 1.68 dB when the visibility is about 8 km.The SNR is increased 0.88 dB when the visibility is about 5 km.And the SNR is increased 0.02 dB when the visibility is about 3 km.