A double threshold correction method for walk error in pulsed laser ranging system

摘要

In pulsed laser ranging system, the influence of nonlinear time walk error is inevitable, especially for the fixed-gain receiver channel. Thus, to correct the walk error involved, the alternative method of leading-edge time discrimination for time interval measurement is adopted first and the compensation principle based on the double threshold correction is proposed in this paper. Firstly, the time domain equations are introduced, which is related to bipolar transistor Gummel-Poon (GP) model and circuit structure, and then simplified by numerical analysis. Secondly, by comparison, the important terms in the equations are retained, and then the relationship between the rise time, which can be regarded as the walk error, and the input amplitude is solved. Finally, based on this relationship, the double threshold correction method is given and corrected experimentally which indicates that the walk error can be greatly reduced to 0.337 ns.