A new lidar signal processor using digital techniques to provide real-time display

An accurate high speed digital data acquisition system which records lidar data on magnetic tape is discussed. It features real-time processing of the data by means of a low cost dedicated processor. The system features dual-channel recording capability, and has two built-in gain-switching amplifiers, allowing the system to accurately record the entire return signal having a dynamic range in excess of 80 dB. Dual differential inputs are used to provide excellent noise immunity. Spatial separations as small as 10 m can be recorded and up to 10 000 returns can be averaged in the 24 bit × 2048 word output buffer memory. This stored data is available to the processor to provide a range corrected signal and a signal normalized for the change in atmospheric density as a function of height. Dual channel operation allows use with dual-wavelength and dual polarization lidars, and the system is sufficiently flexible to be used to record coherent Doppler radar returns.