用于大动态范围厘米精度激光测距的孔径光阑自动调整技术

Automatic adjustment technology of diaphragm used for large dynamic laser ranging with centimetre grade precision

在深空或空间小目标的探测中,需要利用脉冲式激光雷达测量与目标之间的距离。当距离目标由几十千米到几十米范围变化时,探测器接收到的光通量动态范围达60 dB以上。要确保在整个量程范围内信号不饱和,需要采用复合型的自动增益控制技术。除了采用电子学的自动增益方法外,提出了一种自动调整接收光学通光口径的方式,通过对直流电机驱动的电动镜头光圈调整环的逐级调整,实现各级之间2倍光通量的变化。设计并实现了光圈、焦距、聚焦均由直流电机控制的电动镜头的驱动及控制电路,并搭建光路对孔径光阑进行标定,结果表明可以分为8级,且具有很好的重复性,使得全量程范围内准确度达厘米精度测距功能的实现成为可能。

It was necessary to use the Pulsed Laser Radar to measure the distance with the deep spacetarget or space small target. When the distance varied from tens of kilometers to tens meters, the energyrange that photoelectric detector received reaches above 60 dB. To assure the detector not saturated, themultiplex AGC （Automatic Gain Control） technology was required. Except for the electronics method, amethod of adjusting aperture of receive optical automatically was put forward, which made the luminousflux of detector changes 2 times by adjustment of Motorized lens＇ aperture regulation ring step by step,which was driven by direct current motor. The driven and control circuits of motorized lens weredesigned and realized to adjust aperture, zoom and focusing through FPGA software. Optical path wasestablished to calibrate the aperture. The result showed that aperture can be divided into 8 levels, whichhave good repetition characteristic. This make it is impossible to realize laser ranging with centimetergrade precision in the whole detecting field.