高精度时间间隔测量单元(TIU)是星载激光测距仪的关键部件。基于现场可编程门阵列(FPGA)研制出了满足星载要求的高精度、高集成度时间间隔测量单元。该单元采用数字计数法结合数字延迟线插入法的技术,在0.5～10 km的测量距离范围内,时间分辨率为500 ps。通过地面检测,在全程范围内保持了良好的线性度,标准偏差小于270 ps。该单元同时具备测量脉冲回波宽度的能力,可以获取目标的脉冲展宽信息。由于单元选用的元器件都具有航天产品性能,因此其设计和技术指标可满足星载激光测距仪的应用。

High-accuracy time-interval-unit (TIU) is an important component in a spaceborne laser range finder. A highly-integrated TIU with high-accuracy is developed based on field-programmable-gate-array (FPGA) for spaceborne application by combining digital counting and digital delay-line interpolation techniques. The time resolution is about 500 ps when the measurement range is from 0.5 km to 10 km. Detection on the ground verifies that a linear relationship is kept all the range, and the standard error is less than 270 ps. The unit also can measure the width of the returned laser pulses and obtain the pulse broadening characteristics due to different targets. Because every component in the unit has candidate product of aerospace, and the design and technical parameters can be used in high-accuracy range measurement for laser range finder.