ביצועי מד טווח-לייזר על-בסיס סדרות קידוד בתרחישים מרובי מטרות

Multiple-target performance of sequence-coded laser range finder

Laser range-finder technology is central to many defense and civilian applications. It forms the basis of laser radars (or lidars), which are among the leading solutions towards three-dimensional imaging, machine vision and autonomous vehicles applications. Research and development efforts in laser range-finders are increasing rapidly, both in traditional and defense-related industries and in start-up companies. 

The most common principle in laser range-finders is the transmission of intense and isolated pulses, and measurements of the two-way time-of-flight of collected echoes. The peak power levels of transmitted pulses must be high. Hence laser diode sources, which are low-cost and mass-produced for many other applications, cannot be employed in this scheme. 

Over the last three years, our group and collaborators have been developing a different type of laser range-finder, which is based on the transmission of extended sequences of low-power pulses. The range to a target is obtained using digital post-processing which compresses the collected echoes of the long sequence. In 2016, a prototype instrument was built for our group by Civan Technologies Ltd., a Jerusalem-based company that specializes in laser sources. The transmitter was realized based on semiconductor laser diodes and amplifiers only. Measurements were successfully performed up to 1,100 meters range. The project was sponsored by the Ministry of Defense (MAFAT), who also defined its specifications. 

The objective of the proposed project is to quantify, in simulation and experiment, the performance of the above range-finding scheme when multiple reflecting targets are simultaneously present. Since the transmitted sequence of pulses is long, collected echoes from multiple targets are in temporal overlap, and their separation is not necessarily guaranteed. The effects of the laser source specifications, of the code properties and of different detection schemes on multi-target separation will be examined. 

Research tasks include the numerical simulation of the range-finder system, using matlab code, the assembly of a measurement setup in the group research laboratory, the emulation of multiple weak targets using reflective events over fiber, definition of target scenarios, data acquisition and analysis. 

Milestones and formal requirements include: 

• A written mid-term report (to be submitted March 2018, in English)
• Mid-term presentation in the Zadok group meeting (to be given March 2018, in Hebrew)
• A final report (to be submitted no later than September 2018, in English)
• An oral defense and presentation of the project, in front of an examination committee consisted of the project advisors and external experts (to be given in Hebrew, no later than October 2018).
   

דרישות:

Electro-optics track (mandatory), signal processing track (advantage).

מקורות:

Continuously opearting laser range finder based on incoherent compression of periodic sequences," M.Sc. Thesis, Faculty of Engineering, Bar-Ilan Univ., Ramat-Gan, Israel, 2015. http://www.eng.biu.ac.il/zadoka/files/2015/11/msc_thesis_Nadav_Arbel.pdf