Research On Digital Laser Ranging Technology

Laser has long been used in the field of ranging finding because of its superior properties, while the pulsed laser ranging method is the most widely used long-rang distance ranging method. Traditional analog-based laser ranging system has the shortcomings of mass components, heavy weight and weak robustness which is not conductive to the integration and miniature of the laser range finder and cannot make full use of information from the pulses signal. It results in the limitation of accuracy and measurement range.As the limitation of traditional detection of laser range finder echo based on analog method, according to the laser range finder echo receiving and process circuit, this thesis resolved laser echo pulse signals of digital issues using 200MHz ADC AD9481 and high-speed memory. The ranging resolution is 5ns. With a DSP+CPLD system the timing matching between chips and data sampling functions are completed. In the part of data processing, the high-speed DSP (TMS320C5509A) chip builds a hardware platform for high-speed data processing algorithms. In the course of data processing and echo detecting a single echo pulse detection algorithm, the local median filter and of four different echo characteristic time detecting method are used to determine the most accurate echo detection algorithm. Meanwhile, to improve the measurable distance this article proposed a signal accumulation algorithm, which can greatly improve the SNR in the measurement of long-rang goals.This paper has set up experiment platform, collected a large number of data from experiments , verified the feasibility of the hardware and software and then compared the results from the digital system with the analog signal based laser range finder. The experiments show that this digital laser ranging finder can make a great improvement in measurement performance, can achieve ranging precision±1.5m, the farthest measurable distance of more than 12 kilometers. This system have achieved the small-scale technology and met the embedded real-time processing requirements.