Theory and Technology of Laser Imaging Based Target Detection by Yihua Hu

Author:Yihua Hu
Language: eng
Format: epub
Publisher: Springer Singapore, Singapore

The time interval can be computed using the following formula

(4.57)

where, the results of changes randomly in a limitation of .

The maximum error of ranging data induced by above factors is

(4.58)

In fact, the pulse counting method only uses the leading edges of the dominate wave of laser pulses and echoes, while there are two error factors affecting the result of time measurement in terms of the amplitude and time of actual laser pulses [15, 16].

One factor resulting in the error of time discrimination is the different intensities of reflected echoes. Besides, the echo pulses are not standard square waves and have certain inclination at the leading edge. As a result, the instable trigger caused by the varying echo amplitude brings about errors in timing discrimination.

The other factor is the quantization error of counting. Owing to the fact that the appearing times of the dominate waves and echoes are not likely to synchronize with the counting clock, they present a random time difference with the counting clock. The time difference is the so-called quantization error of counting, that is, the above . In order to reduce the quantization error of counting, the most direct way is to improve the frequency of counting pulses. However, the improvement of pulse frequency is also limited by various factors, that is, to achieve a resolution of 0.5 ns in the measurement of the time delay, the frequency of the counter needs to reach 2 GHz.2. High-resolution time delay measurement based on an ADC conversion method

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.