摘要
为了提高相位法激光测距的速度和精度,提出了一种新的相位差放大测量方法,在不增加测量时间的同时将测相精度提高1/N倍,并结合欠采样技术避免了混频器和其他多余器件的使用,减小了串扰对系统的影响。考虑高频弱光信号入射到雪崩光电二极管上会在输出信号上产生相位延迟,提出灵活控制加在雪崩光电二极管上的反向偏压来减小相位延迟的方法,对于调制频率为18.5 MHz,波长为650 nm的激光,当入射光强度为0.5μW时,可将相位延迟从1.4°压缩到0.03°之内。建立了信号串扰产生测相误差的数学模型,并通过实验给出了采取不同屏蔽措施时串扰对测相误差的影响。实验结果表明,采用上述方法,当调制频率为18.5 MHz时,测相精度为0.014°,相应的测距精度可达0.3 mm。
In order to improve the measuring rate and resolution of a phase-shift laser range finder, a new phase shift magnification detecting method is proposed, which improves the measurement resolu- tion by 1/N times without increasing the measuring time. Then, a under-sampling technique is adopt- ed to perform multi-frequency modulation in the same system,which avoids using the mixer and other accessorial components to reduce scheme complexities and the influence of crosstalk. As the phase delay caused by the high frequency weak light incident upon a Avalanche Diode（APD） will induce the distance measurement errors, a new method is presented by controlling the bias voltage acting on APD to suppress the phase delay. For a modulation frequency of 18.5 MHz, a wavelength of 650 nm and an incident light intensity of 0.5μW, the phase delay can be reduced from 1.4° to less than 0.03°. Moreover,a mathematic model is established based on the phase shift measurement errors caused by signal acrosstalks and several kinds of electrostatic screen methods are given to avoid the acrossatlk. Experi- mental results show that adopting those methods mentioned above can get the phase shift measure- ment resolution of 0. 014° and the distance measurement resolution of 0.3 mm accordingly when the modulation is 18.5 MHz.
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2009年第10期2377-2384,共8页
Optics and Precision Engineering
基金
国家自然科学基金资助项目(No.50275040)
关键词
激光测距
接收系统
串扰
欠采样
相位测量
laser range finder
receiver system
crosstalk
under-sampling
phase-shift measurement
