Electronics System Design For Laser Ranging Radar Based On High Speed Pseudorandom Modulation Technique

With the development of laser technique, embedded technology and integrated optics, laser ranging moves toward digitization, automation, low cost, miniaturization. Laser ranging has a series of advantages, such as high measuring accuracy and speed, strong anti-interference capacity, small volume, high weight and easy install. The measuring accuracy of laser ranging is 1-2 order of magnitude higher than general instrument. Laser ranging is used in a wide scope and can be used to measure the length, distance, speed, time, etc. Laser ranging has been one of the most ideal method of measurement.In the paper an electronics system for laser ranging radar based on high speed pseudorandom modulation and photon counting techniques is presented. All functions, such as pseudorandom code transmission, code reception, accumulation, correlation, distance calculation, encoder pulse counting, waveform data output and network communication were integrated into one high-performance FPGA chip of Altera Stratix IV.At present,1550nm laser technology is mature, its pulse repeat frequency can reach 10KHz. In order to adapt to the development of laser technology. The system transmitting and receiving module repeat frequency was 10KHz with 1 GHz code rate. The received codes were accumulated by 10 times and changed to 1 bit binary codes by compared with a settled threshold. The correlation was done in 1ms by using 1024 parallel Exclusive-or operations. The test results under ideal conditions showed the affectivity of the developed system.The article consists of five units, namely, topic background and its significance, general design of the system, system hardware design, system software design, system test and the summary. The first unit introduces the laser ranging technology, the principle of laser ranging radar based on pseudorandom modulation technique and also talks about the significance of this topic. The second unit describes the hardware design of the system in simplicity, which is mainly the interface design between different modules, introduces the main chip selection of the system, hardware and introduces the design of hardware circuit of each module. The third unit is about FPGA logic design and Nios II software design, which is the key part of this article. FPGA logic design mainly accomplishes the data acquisition and processing needed. by the ranging radar and is the most difficult part in this design. The fourth unit is about the system test, which includes lab test and field test. Then this part analyzes the data obtained from the test. The fifth part sums up the conclusions and points out the innovation and the deficiency of this paper.