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  本文關(guān)鍵詞：雙模導(dǎo)航接收機(jī)精密授時系統(tǒng)的設(shè)計與實現(xiàn)　出處：《北方工業(yè)大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 衛(wèi)星導(dǎo)航接收機(jī)授時 鐘差 鎖相環(huán) 預(yù)報 秒脈沖

【摘要】：隨著現(xiàn)代科技的飛速發(fā)展,各行業(yè)對時間和頻率精度提出了更高的要求,并且隨著各大全球衛(wèi)星導(dǎo)航系統(tǒng)的逐步成熟和完善,衛(wèi)星授時技術(shù)以授時范圍廣、精度高等優(yōu)點在授時領(lǐng)域發(fā)揮著重要作用。授時接收機(jī)的工作方式就是接收以原子鐘為時鐘源的衛(wèi)星信號,然后輸出與衛(wèi)星時鐘源同步的時標(biāo)信號(秒脈沖)供其它系統(tǒng)使用。目前市場實際應(yīng)用中大多是單GPS授時接收機(jī),為了提高授時的可靠性和防止對GPS的過度依賴,文中提出采用BDS和GPS雙模系統(tǒng)進(jìn)行授時。 論文主要以提高授時精度為目的,分析和研究了影響授時精度的因素,并提出減少這些因素的影響和提高授時精度需采取的相應(yīng)措施。在授時接收機(jī)中關(guān)鍵是利用鐘差進(jìn)行秒脈沖的調(diào)整,所以鐘差的準(zhǔn)確度直接影響了授時的精度。首先,根據(jù)衛(wèi)星授時原理和偽距方程分析了影響鐘差解算的各個誤差源,通過建立誤差修正模型或采取相應(yīng)措施減小誤差源的影響。其次,為進(jìn)一步提高鐘差的準(zhǔn)確度和秒脈沖的調(diào)節(jié)精度,采用一種基于鎖相環(huán)的鐘差校準(zhǔn)方法。將解算鐘差的方程作為鑒相器,然后將解算的鐘差通過一個三階環(huán)路濾波器,使用濾波過的鐘差對秒脈沖產(chǎn)生進(jìn)行調(diào)節(jié),最后將得到的本地采樣時刻進(jìn)行反饋作為鑒相器的輸入。最后,為實現(xiàn)授時接收機(jī)在衛(wèi)星信號異常時能夠在守時模式下保證其授時精度,利用晶振短時間內(nèi)的穩(wěn)定性,提出利用一組鐘差序列建立相應(yīng)的預(yù)報模型實現(xiàn)短時間內(nèi)鐘差的預(yù)報,由預(yù)報所得鐘差進(jìn)行秒脈沖調(diào)節(jié),從而得到守時時標(biāo)信號。經(jīng)測試,相比于采用直接解算的鐘差進(jìn)行授時,通過授時閉合環(huán)路進(jìn)行授時,其精度可提高將近一倍,可達(dá)到50ns以內(nèi)。另外通過仿真驗證使用AR(p)模型可實現(xiàn)短時間內(nèi)精確的鐘差預(yù)報,精度在5ns以內(nèi)。
[Abstract]:With the rapid development of modern science and technology, various industries put forward higher requirements for the accuracy of time and frequency, and with the gradual maturity and improvement of the major global satellite navigation systems, satellite timing technology to serve a wide range. The advantages of high precision play an important role in the field of timing. The working mode of the timing receiver is to receive the satellite signal with the atomic clock as the clock source. Then the time scale signal (second pulse) synchronized with the satellite clock source is output for other systems. At present, most of the actual market applications are single GPS timing receiver. In order to improve the reliability of timing service and prevent excessive dependence on GPS, a dual mode system of BDS and GPS is proposed in this paper. In order to improve the precision of timing, the paper analyzes and studies the factors that affect the accuracy of timing. The measures to reduce the influence of these factors and to improve the accuracy of time service are put forward. The key of the timing receiver is to use the clock difference to adjust the second pulse. Therefore, the accuracy of clock error directly affects the accuracy of timing service. Firstly, according to the principle of satellite timing service and pseudo-range equation, the error sources that affect the solution of clock difference are analyzed. Through establishing error correction model or taking corresponding measures to reduce the influence of error source. Secondly, to further improve the accuracy of clock error and the adjustment accuracy of second pulse. A clock difference calibration method based on phase-locked loop is adopted. The equation of calculating clock error is used as phase discriminator, then the clock difference is calculated through a third-order loop filter, and the second pulse generation is adjusted by the filtered clock difference. Finally, the local sampling time feedback is used as the input of the phase discriminator. Finally, in order to realize the timing receiver can ensure its timing accuracy in the time-saving mode when the satellite signal is abnormal. Based on the stability of crystal oscillator in a short period of time, a corresponding prediction model is established by using a set of clock difference sequences to predict the clock error in a short time, and the clock difference obtained from the prediction is adjusted by second pulse. Therefore, the time-keeping signal is obtained. Compared with the clock difference of the direct solution, the precision of the time-keeping signal can be improved by nearly twice as much as that by the closed loop of time-sharing. In addition, the precision of clock error prediction in a short period of time can be realized by using the ARGRP) model, and the precision is less than 5 ns.
【學(xué)位授予單位】：北方工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：P228.4

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本文編號：1356742