發(fā)布時間：2019-06-05 09:43

【摘要】：無線激光通信是以激光束作為信息載體在空間直接進(jìn)行信息雙向傳輸?shù)囊环N技術(shù),又稱為“自由空間激光通信”。在大氣激光通信系統(tǒng)中,由于激光的光束窄、方向性強(qiáng),要求發(fā)射機(jī)的場功率確實(shí)到達(dá)接收機(jī)的光檢測器,給通信鏈路的建立和維持帶來了困難,所以信號的精確對準(zhǔn)顯得尤為重要。捕獲、對準(zhǔn)與跟蹤系統(tǒng)技術(shù)是用于建立和確保通信鏈路可靠連接的關(guān)鍵,對無線激光通信系統(tǒng)至關(guān)重要。本文主要工作如下:1、本文對捕獲、對準(zhǔn)與跟蹤系統(tǒng)中光斑檢測單元常用的三種光電探測器的性能進(jìn)行了對比分析。研究了在不同光斑能量分布模型下四象限探測器的偏移量計算方法,推導(dǎo)了高斯橢圓模型及環(huán)形光斑模型下偏移量計算公式。2、對光束在光軸中的對準(zhǔn)技術(shù)進(jìn)行了分析,將破碎光斑建模為高斯橢圓光斑,分析了破碎光斑與高斯完整光斑的位置誤差。針對同時存在方位偏移及俯仰誤差的情況,提出了一種適用于捕獲、對準(zhǔn)與跟蹤系統(tǒng)的光軸對準(zhǔn)方法。解決了當(dāng)光束存在漂移、入射光束與天線視軸不平行同時存在而四象限探測器無法分別探測的問題。3、利用STM32實(shí)現(xiàn)了以四象限探測器為光電轉(zhuǎn)換器件的光斑精確檢測對準(zhǔn)系統(tǒng),確定系統(tǒng)設(shè)計方案,包括光學(xué)器件、驅(qū)動電路、電源模塊、數(shù)據(jù)傳輸接口以及終端軟件設(shè)計等。搭建了系統(tǒng)實(shí)驗(yàn)平臺,包括硬件結(jié)構(gòu)平臺以及軟件環(huán)境平臺。完成了光斑檢測及自適應(yīng)閾值對準(zhǔn)實(shí)驗(yàn);驗(yàn)證了本文方法可以有效檢測入射光束的狀態(tài)值,提高了檢測的準(zhǔn)確度;驗(yàn)證了本文方法具有實(shí)現(xiàn)簡單、準(zhǔn)確性高和數(shù)據(jù)處理復(fù)雜度低等優(yōu)點(diǎn)。
[Abstract]:Wireless laser communication is a kind of technology which uses laser beam as information carrier to transmit information directly in space, also known as "free space laser communication". In the atmospheric laser communication system, because of the narrow beam and strong directivity of the laser beam, the field power of the transmitter is required to reach the photodetector of the receiver, which brings difficulties to the establishment and maintenance of the communication link. Therefore, the accurate alignment of the signal is particularly important. Acquisition, alignment and tracking system technology is the key to establish and ensure reliable connection of communication link, which is very important to wireless laser communication system. The main work of this paper is as follows: 1. The performance of three kinds of photodetector commonly used in spot detection unit in acquisition, alignment and tracking system is compared and analyzed in this paper. The offset calculation method of four quadrant detector under different spot energy distribution models is studied, and the formulas for calculating the offset under Gao Si elliptical model and annular spot model are derived. 2, the alignment technique of beam in optical axis is analyzed. The broken spot is modeled as Gao Si elliptical spot, and the position error between broken spot and Gao Si complete spot is analyzed. In view of the simultaneous azimuth offset and pitch error, an optical axis alignment method for acquisition, alignment and tracking systems is proposed. It solves the problem that when the beam drifts, the incident beam does not exist at the same time as the apparent axis of the antenna, and the four-quadrant detector can not detect it separately. 3, The spot accurate detection and alignment system with four quadrant detector as photoelectric conversion device is realized by STM32, and the design scheme of the system is determined, including optical device, driving circuit, power supply module, data transmission interface and terminal software design. The experimental platform of the system is built, including the hardware structure platform and the software environment platform. The experiments of spot detection and adaptive threshold alignment are completed, and it is verified that the proposed method can effectively detect the state value of the incident beam and improve the accuracy of the detection. It is verified that the method has the advantages of simple implementation, high accuracy and low complexity of data processing.
【學(xué)位授予單位】：西安理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN929.1

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本文編號：2493436