本文選題：衛(wèi)星授時　切入點：時間同步　出處：《西安工業(yè)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：時間的重要意義不言而喻。隨著科技的快速進步,在通信、軍事和空間探索等領(lǐng)域?qū)r間同步的精度要求越來越高,如何能夠?qū)崿F(xiàn)高精度的時間同步也成為了學(xué)者研究的熱點和重點。本文研究了基于衛(wèi)星授時的高精度時間同步方法,該方法綜合考慮了衛(wèi)星授時信號具有的全球性、全天時、全天候覆蓋的特點,衛(wèi)星接收機輸出的1PPS信號具有較高的長期平均準確度和穩(wěn)定度的特點,并且恒溫晶振的輸出頻率具有較高的短期穩(wěn)定性的特點。使用衛(wèi)星授時信號對恒溫晶振進行馴服,馴服后的恒溫晶振作為頻率源能夠輸出高精度的頻率信號,從而可以構(gòu)成基于衛(wèi)星授時的高精度時間同步系統(tǒng)。在基于衛(wèi)星授時的高精度時間同步方法研究中,利用衛(wèi)星接收機鎖定衛(wèi)星后輸出1PPS信號,將該信號作為參考頻率信號;在FPGA中實現(xiàn)倍頻,分頻和時間間隔測量功能,FPGA中對恒溫晶振進行倍頻和分頻處理,時間間隔測量方法使用脈沖計數(shù)法,測量恒溫晶振分頻1Hz信號和1PPS信號之間的時間間隔差值,測量完成后產(chǎn)生中斷;數(shù)據(jù)處理模塊從FPGA中讀取時間間隔差值,通過滑動中位數(shù)算法剔除數(shù)據(jù)序列中的異常值,然后采用無偏FIR濾波算法對時間間隔差值進行處理,消除毛刺和減弱隨機抖動,得到相對真實的時間差值,最后使用數(shù)字PID控制算法計算出控制量;通過高性能的DA轉(zhuǎn)換模塊將控制量轉(zhuǎn)換成模擬電壓輸入到恒溫晶振的壓控輸入端,調(diào)節(jié)恒溫晶振輸出穩(wěn)定,最終實現(xiàn)1PPS信號與恒溫晶振的分頻信號保持高度同步,誤差在30ns以內(nèi)。最后,考慮到衛(wèi)星信號容易受到干擾或丟失,無法作為參考頻率信號使用,本文論述了利用預(yù)測控制算法依靠歷史數(shù)據(jù)對晶振進行調(diào)節(jié),使其輸出頻率在一段時間保持較高的精度。綜合上述的技術(shù),本文在基本原理的基礎(chǔ)上設(shè)計了一個基于衛(wèi)星授時的時間同步系統(tǒng)的樣機,介紹了系統(tǒng)的相關(guān)硬件設(shè)計和軟件設(shè)計流程,以及濾波和控制算法的實現(xiàn)等。設(shè)計了上位機軟件對系統(tǒng)進行了測試,通過分析實驗的數(shù)據(jù),利用該方法可以在一定程度上改善恒溫晶振的長期平均準確度和長期穩(wěn)定度,作為高精度時間同步系統(tǒng)的頻率源。
[Abstract]:The importance of time is self-evident. With the rapid development of science and technology, the accuracy of time synchronization is becoming more and more demanding in the fields of communication, military and space exploration. How to achieve high precision time synchronization has also become a hot topic and focus of scholars. In this paper, a high precision time synchronization method based on satellite timing is studied. This method takes into account the global and all-day time of satellite timing signals. With all-weather coverage, the 1PPS signal output from the satellite receiver has the characteristics of high long-term average accuracy and stability. And the output frequency of the thermostatic crystal oscillator has the characteristics of high short-term stability. Using the satellite timing signal to tame the constant temperature crystal oscillator, the tamed constant temperature crystal oscillator can output high precision frequency signal as the frequency source. Therefore, a high precision time synchronization system based on satellite timing can be constructed. In the research of high precision time synchronization method based on satellite timing service, the 1PPS signal is output by using satellite receiver after locking the satellite, and the signal is taken as the reference frequency signal. The function of frequency doubling, frequency division and time interval measurement is realized in FPGA. The frequency doubling and frequency division processing of constant temperature crystal oscillator is carried out in FPGA. The time interval measurement method uses pulse counting method to measure the time interval difference between 1Hz signal and 1PPS signal. The data processing module reads the time interval difference from the FPGA, removes the outlier value from the data sequence by sliding median algorithm, and then processes the time interval difference by using the unbiased FIR filter algorithm. Eliminating burr and weakening random jitter, the relative real time difference is obtained. Finally, the control quantity is calculated by using digital PID control algorithm. Through the high performance DA conversion module, the control quantity is converted into analog voltage input to the voltage control input of the constant temperature crystal oscillator, and the output of the constant temperature crystal oscillator is adjusted stably. Finally, the 1PPS signal and the frequency division signal of the constant temperature crystal oscillator are kept in high synchronization. The error is within 30 ns. Finally, considering that the satellite signal is easily disturbed or lost and can not be used as a reference frequency signal, this paper discusses how to adjust the crystal oscillator by using predictive control algorithm based on historical data. In this paper, a prototype of time synchronization system based on satellite timing is designed on the basis of the basic principle. This paper introduces the related hardware design and software design flow of the system, as well as the realization of filtering and control algorithm, etc. The software of upper computer is designed to test the system, and the data of the experiment are analyzed. The method can improve the long-term average accuracy and long-term stability of the thermostatic crystal oscillator to a certain extent and can be used as the frequency source of the high-precision time synchronization system.
【學(xué)位授予單位】：西安工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TP273;TN752;P127.1

【參考文獻】

相關(guān)期刊論文 前10條

1 閻玉英;趙富;;SC切恒溫晶振老化特性補償方法[J];無線電工程;2014年12期

2 孫兵鋒;閻世棟;陳濤;侯林山;鐘達;梅剛?cè)A;;小型化10 MHz恒溫晶體振蕩器設(shè)計[J];波譜學(xué)雜志;2014年03期

3 楊劍青;楊曉琴;謝亮;蘆旭;樊戰(zhàn)友;;基于ARM與CPLD的可馴頻率基準的設(shè)計與實現(xiàn)[J];電子測量技術(shù);2014年02期

4 楊前利;;基于數(shù)字PID的閉環(huán)溫度控制系統(tǒng)的設(shè)計[J];計算機與數(shù)字工程;2013年12期

5 張杰;周棟明;;GPS馴服中無偏滑動平均濾波算法的研究[J];電子學(xué)報;2013年02期

6 沈乃o，

本文編號：1557285