【作者】 陈栋；

【导师】 刘恩海；

【作者基本信息】 中国科学院研究生院（光电技术研究所） ， 控制工程， 2014， 硕士

【摘要】 激光测距因其优异的特性，在航空航天、环境探测、精密制造等领域得到重用。在空间位置的近距离、高精度测量中，相位式激光测距凭借精度高、功耗和体积小、重量轻等优点，成为首选的传感器。课题以相位式激光测距为背景，初步完成了系统总体的设计，并针对相位差测量、APD温漂、频率源设计等影响测距精度的关键因素，以提高系统测距的精度为目标开展研究工作。首先，选择合适的鉴相方法对提高测距精度起到关键作用。本文对谱分析法的FFT和apFFT进行鉴相性能对比，通过理论分析和仿真实验，得出了在单次鉴相使用数据量相等，且系统频率偏移很小的情况下，FFT鉴相精度更高的结论。结合具体系统参数，选择FFT谱分析法作为鉴相方法。其次，APD倍增因子会随温度变化而发生漂移，造成测距误差。为了抑制温漂的影响，根据APD倍增因子不变时，偏压和温度之间的关系，设计了偏压控制电路。实验结果表明，该电路能在-10oC~55oC的范围内，跟随温度变化自动调节APD的偏压，且该偏压与温度有良好的线性关系，以保证测量过程中APD的倍增因子稳定。最后，频率源设计的好坏对测距精度有很重要的影响。在对常用的频率合成技术进行比较后，考虑系统参数，采用恒温晶振、DDS、PLL来共同实现频率源的功能，并完成了电路的制作。课题的研究为相位式激光测距仪的研制打下了基础，并完成了部分设计和制作的任务。更多还原

【Abstract】 Laser range finding is chosen by virtue of its excellent performance in areassuch as aerospace technology, environment detection, precision manufacturing andso on. Phase-shift laser range finder becomes the preferred sensor in close range,high precision spatial position measurement, by virtue of merits such as highaccuracy, low power consumption, small volume, light weight and so on.On the background of phase-shift laser range finding, this thesis implements thesystem’s overall design scheme preliminarily. Aimed at key factors affectingranging accuracy such as phase difference measurement, temperature drift of thedetector and frequency source design, this subject begins research on improving thesystem’s accuracy of range finding.Firstly, choosing a proper phase discrimination method is the key to improvingthe accuracy of ranging. This thesis compares FFT and apFFT in phasediscrimination performance. Theoretical analysis and simulation experimentsindicate that FFT achieves higher accuracy than apFFT using the same length ofsampled data when system’s frequency deviation is small. Considering the actualsystem parameters, FFT is chosen as the phase discrimination method.Secondly, the multiplication factor of APD drifts with the change of temperature,which will result in ranging error. In order to restrict the influence of temperaturedrift, a bias voltage control circuit is designed according to the numericalrelationship between bias voltage of APD and temperature when APD’s gain isconstant. This circuit can automatically adjust the bias voltage of APD followingthe changing temperature in the range of-10oC~55oC with good linearity, thus themultiplication factor of APD remains constant during range measurement.At last, the design of the frequency source has an important influence on theranging accuracy. By comparing frequently-used frequency synthesis techniques,OCXO, DDS and PLL are chosen to implement the frequency synthesis circuitconsidering the system parameters. The fabrication of the circuit is completed.The research of this subject lays a foundation for the development ofphase-shift laser range finder, and also completed several design and fabricating tasks.更多还原