甚長基線干涉測量精密定軌技術(shù)
發(fā)布時間：2018-11-05 18:09
【摘要】：傳統(tǒng)的航天測控網(wǎng)采用雷達(dá)測距和多普勒測速作為航天器跟蹤測量的主要技術(shù)手段,但這兩種無線電測量技術(shù)對飛行器的橫向位置和橫向速度并不敏感,隨著探測距離的增加,受測量精度的制約和系統(tǒng)誤差變大的影響,以角度表示的測量精度會變得很差,無法滿足航天測控的需要。甚長基線干涉測量技術(shù)(Very Long Baseline Interferometry,VLBI)能獲得極高的角分辨率,在航天測控領(lǐng)域發(fā)揮了重要的作用。本文圍繞對探月衛(wèi)星測控通信系統(tǒng)中的VLBI子系統(tǒng)仿真的研究,開展了以下三個方面的工作:對擴(kuò)頻VLBI子系統(tǒng)中的幾種擴(kuò)頻偽隨機(jī)碼進(jìn)行了分析比較。闡述了m序列、Gold序列以及JPL(Jct Propulsion Laboratory)快捕碼的產(chǎn)生原理,并通過仿真結(jié)果驗(yàn)證了在周期長度在同一量級的情況下,JPL快捕碼的捕獲速度比m序列快得多;然后結(jié)合偽碼測距原理,提出了擴(kuò)頻偽隨機(jī)碼在擴(kuò)頻以外的另一個用途,即通過計算兩地面站接收信號的偽碼偏移量之差求兩站的時延估計值,因此特別針對JPL快速捕獲碼進(jìn)行了仿真設(shè)計,設(shè)定合適的碼周期及碼速率,使其滿足后續(xù)根據(jù)偽碼偏移量之差求時延補(bǔ)償值的精度要求。對VLBI擴(kuò)頻信號捕獲跟蹤方法進(jìn)行了深入研究。針對傳統(tǒng)的相關(guān)檢測的捕獲方法捕獲過程困難、捕獲時間長這一問題,研究了基于FFT(Fast Fourier Transformation)的并行頻域搜索捕獲算法,變偽碼相位與頻率的二維搜索為偽碼相位的一維搜索,頻率的搜索通過傅里葉變換一次性完成;并針對JPL復(fù)合碼在此算法上做了改進(jìn),采用四路并行結(jié)構(gòu)同時搜索復(fù)合碼中各子碼的相位,仿真驗(yàn)證了該算法的搜索次數(shù)大大減少。同樣為獲得精確的偽碼相位、載波相位,研究設(shè)計非相干型DDLL(Digital Delay Lock Loop)偽碼延遲鎖定環(huán)及科斯塔斯載波跟蹤環(huán)(Costas PLL),仿真驗(yàn)證了偽碼及載波精確跟蹤問題得以解決。對擴(kuò)頻VLBI系統(tǒng)數(shù)據(jù)相關(guān)處理機(jī)進(jìn)行了深入研究。針對兩路信號在相關(guān)運(yùn)算前需要做時延補(bǔ)償這一點(diǎn),提出了一種通過計算兩臺站接收信號的偽碼偏移量之差求得時延補(bǔ)償值的方法,并用Simulink仿真驗(yàn)證了該方法有效可行;然后通過觀察干涉條紋幅度值,進(jìn)行粗搜索和精搜索兩個步驟求得精確的時延值;最后,選取三條獨(dú)立基線的時延值,使用衛(wèi)星單點(diǎn)定位法進(jìn)行衛(wèi)星位置坐標(biāo)的解算。
[Abstract]:The traditional space TT & C network uses radar ranging and Doppler velocimetry as the main technical means of spacecraft tracking and measurement, but these two radio measurement techniques are not sensitive to the lateral position and lateral velocity of the aircraft, and with the increase of the detection range, Because of the restriction of measurement precision and the increase of system error, the measurement precision expressed by angle will become very poor, which can not meet the needs of space measurement and control. Very long baseline interferometry (Very Long Baseline Interferometry,VLBI), which can obtain very high angular resolution, plays an important role in the field of space measurement and control. This paper focuses on the simulation of the VLBI subsystem in the lunar probe satellite TT & C communication system. The following three aspects are carried out: the analysis and comparison of several spread spectrum pseudorandom codes in the spread spectrum VLBI subsystem. The generation principle of m sequence, Gold sequence and JPL (Jct Propulsion Laboratory) fast capture code is expounded. The simulation results show that the capture speed of JPL fast capture code is much faster than m sequence when the period length is of the same order of magnitude. Then, combining the principle of pseudo-code ranging, the author puts forward another application of spread spectrum pseudorandom code in addition to spread spectrum, that is, by calculating the difference of pseudo-code offset between two earth stations, the time delay estimation value of two stations is obtained. Therefore, the JPL fast acquisition code is simulated and designed, and the appropriate code period and code rate are set to meet the accuracy requirements of the delay compensation value obtained by the difference of the pseudo code offset. The acquisition and tracking method of VLBI spread spectrum signal is studied in detail. Aiming at the difficulty of traditional acquisition method of correlation detection and the long acquisition time, a parallel frequency-domain search and acquisition algorithm based on FFT (Fast Fourier Transformation) is studied. The two dimensional search of the phase and frequency of the pseudo code is one dimensional search of the phase of the pseudo code, and the search of the frequency is completed by Fourier transform at one time. The algorithm is improved for JPL complex codes, and the phase of each subcode in the complex code is simultaneously searched by four parallel structures. The simulation results show that the search times of the algorithm are greatly reduced. In order to obtain accurate pseudo-code phase and carrier phase, the incoherent DDLL (Digital Delay Lock Loop) pseudo-code delay locking loop and Kostas carrier tracking loop are designed and simulated. The results show that the pseudo-code and carrier precise tracking problem can be solved. The data correlation processor of spread spectrum VLBI system is studied in detail. Aiming at the time delay compensation of two signals before the correlation operation, a method of calculating the difference of pseudo code offset between two stations is proposed, and the method is proved to be effective and feasible by Simulink simulation. Then, by observing the amplitude of interference fringes, two steps of coarse search and fine search are carried out to obtain the accurate delay value. Finally, the satellite position coordinates are calculated by using the satellite single point positioning method, which selects the delay values of three independent baselines.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P228.6
[Abstract]:The traditional space TT & C network uses radar ranging and Doppler velocimetry as the main technical means of spacecraft tracking and measurement, but these two radio measurement techniques are not sensitive to the lateral position and lateral velocity of the aircraft, and with the increase of the detection range, Because of the restriction of measurement precision and the increase of system error, the measurement precision expressed by angle will become very poor, which can not meet the needs of space measurement and control. Very long baseline interferometry (Very Long Baseline Interferometry,VLBI), which can obtain very high angular resolution, plays an important role in the field of space measurement and control. This paper focuses on the simulation of the VLBI subsystem in the lunar probe satellite TT & C communication system. The following three aspects are carried out: the analysis and comparison of several spread spectrum pseudorandom codes in the spread spectrum VLBI subsystem. The generation principle of m sequence, Gold sequence and JPL (Jct Propulsion Laboratory) fast capture code is expounded. The simulation results show that the capture speed of JPL fast capture code is much faster than m sequence when the period length is of the same order of magnitude. Then, combining the principle of pseudo-code ranging, the author puts forward another application of spread spectrum pseudorandom code in addition to spread spectrum, that is, by calculating the difference of pseudo-code offset between two earth stations, the time delay estimation value of two stations is obtained. Therefore, the JPL fast acquisition code is simulated and designed, and the appropriate code period and code rate are set to meet the accuracy requirements of the delay compensation value obtained by the difference of the pseudo code offset. The acquisition and tracking method of VLBI spread spectrum signal is studied in detail. Aiming at the difficulty of traditional acquisition method of correlation detection and the long acquisition time, a parallel frequency-domain search and acquisition algorithm based on FFT (Fast Fourier Transformation) is studied. The two dimensional search of the phase and frequency of the pseudo code is one dimensional search of the phase of the pseudo code, and the search of the frequency is completed by Fourier transform at one time. The algorithm is improved for JPL complex codes, and the phase of each subcode in the complex code is simultaneously searched by four parallel structures. The simulation results show that the search times of the algorithm are greatly reduced. In order to obtain accurate pseudo-code phase and carrier phase, the incoherent DDLL (Digital Delay Lock Loop) pseudo-code delay locking loop and Kostas carrier tracking loop are designed and simulated. The results show that the pseudo-code and carrier precise tracking problem can be solved. The data correlation processor of spread spectrum VLBI system is studied in detail. Aiming at the time delay compensation of two signals before the correlation operation, a method of calculating the difference of pseudo code offset between two stations is proposed, and the method is proved to be effective and feasible by Simulink simulation. Then, by observing the amplitude of interference fringes, two steps of coarse search and fine search are carried out to obtain the accurate delay value. Finally, the satellite position coordinates are calculated by using the satellite single point positioning method, which selects the delay values of three independent baselines.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P228.6
【參考文獻(xiàn)】
相關(guān)期刊論文 前3條
1 陳略;唐歌實(shí);王美;劉薈萃;李黎;;干涉測量寬帶相關(guān)處理算法與驗(yàn)證[J];飛行器測控學(xué)報;2011年06期
2 王剛;武小悅;;美國航天測控系統(tǒng)的構(gòu)成及發(fā)展[J];國防科技;2010年05期
3 胡小工,黃s，
本文編號：2312913
本文鏈接：http://sikaile.net/kejilunwen/dizhicehuilunwen/2312913.html
最近更新
教材專著
