Fpga Hardware Realization Of Extended Beacon Algorithm Of Pointing Acquisition Tracking In Deep Space Optical Communications

Deep space optical communications can be considered as the consequent evolution of deep space detection in the future towards higher data rate, and it holds a potential performance contrast to microware communication in terms of higher data capacity, smaller terminals and low probability of intercept. In deep space optical communication, the requirement of precise pointing and tracking is need for both optical terminals, because the distance of link is too far and the special environment is too bad. Acquisition and tracking technology used for the setting up and keeping up of laser link is critical to a deep space optical communication system. It is the kernel of this system. This dissertation is concerned with designs algorithms according to two theoretical models of acquisition and tracking, and designs hardware system after the software simulation be succeeded, and realizes the algorithms by FPGA.First of all, introduces extended beacon mechanism of pointing acquisition tracking (PAT) in deep space optical communication. When the spacecraft located at solar system, the heavenly body's image on the beacon detector is usually extended to several pixels, called the extended beacon. The kernel of PAT mechanism of extended beacon is the precise computation of beacon's center. So the image processing algorithm is a core. Analyzes the common hardware project of image processing, and compares the various projects. Combined with the hardware development and the characteristics of the image processing algorithms of this dissertation, we bring forward this FPGA-based image processing system.Analyzes the theoretical model that base on extended beacon PAT mechanism in deep space optical communication.Acquisition is to search out beacon in the uncertainty areas and calculate beacon's center. Tracking is to calculate the rotation and translation of beacon because of spacecraft's motion after the beacon has been captured. The core theory of the two processes is Fourier-Mellin transformation. In order to reduce the time of image matching in the acquisition, this dissertation proposes that divide the matching into two steps of coarse matching and fine matching. Uses different pattern plate and reduces the gap of pattern plate gradually are used in the coarse matching.Analyzes the function of the image processing system in deep space optical communication according to this dissertation's requests, and carries on the functional module division to the system. Finally completes the design of PCB board. We select the commercial board EP2S60 for the following simulation and download verification.Finally, analyzes the realization processes of acquisition's and tracking's algorithms in the FPGA. Uses QuartusⅡsoftware to carry on the FPGA design. Uses modular design method, divides the entire process into four modules: communication module, memory module, FFT module and operation module. Analyzes the construction process of each module and then simulate each module. Finally, the algorithms are downloaded to the hardware verification.This dissertation's work provides a preliminary model and design method for the hardware realization of extended beacon PAT mechanism in deep space optical communications.