本文選題：衛(wèi)星測(cè)控體制　切入點(diǎn)：被動(dòng)解調(diào)　出處：《電子科技大學(xué)》2014年碩士論文

【摘要】：隨著時(shí)代的發(fā)展,衛(wèi)星測(cè)控技術(shù)在軍用和民用方面,都在發(fā)揮越來越大的作用,二次調(diào)制技術(shù)被廣泛用于衛(wèi)星測(cè)控領(lǐng)域。本文主要研究了衛(wèi)星測(cè)控系統(tǒng)中常用的統(tǒng)一載波調(diào)制信號(hào)的時(shí)頻特征,參數(shù)估計(jì)方法與被動(dòng)解調(diào)方法。主要完成了PCM/PM,PCM/FM,PCM/BPSK/PM,PCM/QPSK/PM,DSSS/BPSK五類信號(hào)的調(diào)制識(shí)別、參數(shù)估計(jì)與解調(diào)。對(duì)于上述問題本文的主要工作如下:首先研究了統(tǒng)一載波調(diào)制信號(hào)的調(diào)制特性和時(shí)頻特性,然后再根據(jù)其不同的特征,如頻域特征、平方譜特征、高階累積量、正交變換后得到的載波分量和信息分量等、設(shè)計(jì)了一套識(shí)別流程:通過信號(hào)平方譜性質(zhì)識(shí)別出DSSS/BPSK信號(hào);通過信號(hào)的譜線單一性區(qū)分出PCM/PM信號(hào);通過信號(hào)的信息分量識(shí)別PCM/PM信號(hào),最后通過信息分量的平方譜和四次方譜區(qū)分PCM/BPSK/PM和PCM/QPSK/PM信號(hào),并給出仿真結(jié)果。仿真表明在信噪比SNR?5的環(huán)境下,調(diào)制類型正確識(shí)別率可以達(dá)到90%以上。其次在調(diào)制識(shí)別得到的信號(hào)類型的基礎(chǔ)上,可以根據(jù)其信號(hào)特性,估計(jì)出一些關(guān)鍵參數(shù),如碼速率、載波頻率、副載波頻率、調(diào)制指數(shù)等等。對(duì)于統(tǒng)一載波調(diào)制信號(hào)解調(diào),本文采用了鎖相環(huán)結(jié)構(gòu),實(shí)現(xiàn)了對(duì)主載波的跟蹤,并通過對(duì)副載波信號(hào)支路的數(shù)字鑒相實(shí)現(xiàn)了對(duì)PCM/PM的解調(diào),數(shù)字鑒頻實(shí)現(xiàn)了對(duì)PCM/FM的解調(diào);通過鎖相環(huán)來進(jìn)行副載波的跟蹤,實(shí)現(xiàn)了對(duì)PCM/BPSK/PM以及PCM/QPSK/PM的解調(diào);通過估計(jì)出的偽隨機(jī)碼序列,實(shí)現(xiàn)了擴(kuò)頻信號(hào)的解擴(kuò),從而完成信號(hào)解調(diào)。仿真結(jié)果表明,在信噪比SNR?5的環(huán)境下,信號(hào)的解調(diào)誤碼率低于110?。
[Abstract]:With the development of the times, satellite TT & C technology is playing a more and more important role in both military and civil fields. Secondary modulation technology is widely used in satellite TT & C field.In this paper, the time-frequency characteristics, parameter estimation methods and passive demodulation methods of unified carrier modulation signals in satellite TT & C systems are studied.We mainly completed the modulation identification, parameter estimation and demodulation of five kinds of PCM / PM / PM / PC / PM / PM / QSSS / BPSK signals of PCM / PM / FM / PCM / PM / PM / PCM / QPSK / PMX / DSSS / BPSK.The main work of this paper is as follows: firstly, the modulation characteristics and time-frequency characteristics of unified carrier modulated signals are studied, and then according to their different characteristics, such as frequency domain characteristics, squared spectrum features, high-order cumulants,The carrier component and information component obtained by orthogonal transform are designed to identify the DSSS/BPSK signal by the character of signal squared spectrum, to distinguish the PCM/PM signal by the single spectral line of the signal, and to recognize the PCM/PM signal by the information component of the signal.Finally, the PCM/BPSK/PM and PCM/QPSK/PM signals are distinguished by the square spectrum of the information component and the quadrilateral spectrum, and the simulation results are given.Simulation results show that the correct recognition rate of modulation type can reach over 90% under the environment of signal-to-noise ratio (SNR?5).Secondly, on the basis of the signal types obtained by modulation recognition, some key parameters, such as code rate, carrier frequency, subcarrier frequency, modulation index and so on, can be estimated according to their signal characteristics.For the demodulation of the unified carrier modulation signal, this paper adopts the phase-locked loop structure, realizes the tracking of the main carrier, and realizes the demodulation of the PCM/PM and the demodulation of the PCM/FM by the digital phase discrimination of the sub-carrier signal branch.The demodulation of PCM/BPSK/PM and PCM/QPSK/PM is realized by using phase-locked loop to track subcarriers, and the despreading of spread spectrum signal is realized by estimating the pseudorandom code sequence, thus the demodulation of the signal is completed.The simulation results show that the bit error rate (BER) of signal demodulation is lower than 110g in the environment of signal-to-noise ratio (SNR?5).
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：V556;TN911.3

【參考文獻(xiàn)】

相關(guān)期刊論文 前2條

1 彭耿;黃知濤;姜文利;周一宇;;角度調(diào)制信號(hào)調(diào)制指數(shù)盲估計(jì)研究[J];電子學(xué)報(bào);2010年04期

2 莫乾坤;何晨;;星載數(shù)字化TDRSS/USB雙模應(yīng)答機(jī)設(shè)計(jì)與試驗(yàn)[J];無線通信技術(shù);2008年03期

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本文編號(hào)：1703483