發(fā)布時間：2018-04-24 09:53

  本文選題：BOC調(diào)制 + SPART算法��； 參考：《上海交通大學(xué)》2014年博士論文

【摘要】：在現(xiàn)代導(dǎo)航系統(tǒng)中，BOC調(diào)制信號的采用使導(dǎo)航系統(tǒng)間實(shí)現(xiàn)頻譜共享，同時提高定位精度和抗多徑干擾的能力成為可能。但是,BOC信號子載波調(diào)制所帶來的同步模糊性是當(dāng)今亟待解決的關(guān)鍵熱門問題。由于BOC信號自相關(guān)函數(shù)的多峰值特性，曾經(jīng)適用于BPSK信號的同步算法已不再適用。本文在深入研究BOC調(diào)制信號特性和傳統(tǒng)同步方案的基礎(chǔ)上，提出了三種解決同步模糊性的算法。 提出了SPART(Symmetrical Pulse Ambiguity Removing technique)非模糊性同步算法：算法的原理是構(gòu)造兩個本地BOC-like信號，其中一個是偶對稱的，另外一個是奇對稱的信號。通過合成這兩個本地信號與BOC信號的互相關(guān)函數(shù)來獲得具有非模糊性的相關(guān)函數(shù)。合成的相關(guān)函數(shù)僅含有一個正的相關(guān)峰值，所有的旁峰都被消除掉了,從而巧妙地消除了旁峰對捕獲和跟蹤處理的潛在威脅。文中不但給出了SPART算法的實(shí)現(xiàn)環(huán)路結(jié)構(gòu)，同時從基于Monte Carlo的仿真分析和基于FPGA的硬件平臺對SPART算法的有效性進(jìn)行了驗(yàn)證。對捕獲檢測概率和跟蹤標(biāo)準(zhǔn)差的表達(dá)式做了理論上的推導(dǎo)。仿真發(fā)現(xiàn)，SPART算法不僅適合正弦BOC信號，也適用于余弦BOC信號，，但針對余弦BOC信號時，SPART算法采用的本地信號的脈寬是針對正弦BOC信號脈寬的一半。SPART算法與傳統(tǒng)同步算法對比分析發(fā)現(xiàn)，在相同積分時間，碼間距和累加次數(shù)的情況下，針對低調(diào)制系數(shù)的BOC信號，SPART算法在捕獲和跟蹤階段與傳統(tǒng)跟蹤環(huán)路相比有很小的性能退化。調(diào)制系數(shù)越高，BOC信號退化越嚴(yán)重。但是不要忘了SPART算法的初衷是消除BOC信號自相關(guān)函數(shù)中正的側(cè)峰以免捕獲到側(cè)峰上和鎖定到錯誤的鑒相器零點(diǎn)上。另外，為了補(bǔ)償SPART算法的性能退化，我們可以通過增加相干積分時間，增加非相干累加次數(shù)和減小碼間距的方法來提高算法的性能。 提出了適合BOC(n,n)和MBOC信號的GFSA(Gating function Shifting Algorithm)非模糊性算法：算法的原理是構(gòu)造一個選通脈沖信號去調(diào)制本地的PRN碼和子載波信號，調(diào)制后的本地信號與接收到的BOC進(jìn)行互相關(guān)運(yùn)算，相關(guān)函數(shù)向左和向右移位產(chǎn)生的兩個相關(guān)函數(shù)，當(dāng)選通函數(shù)的脈沖寬度在[0.51]個碼片范圍內(nèi)時，它們和的能量減去差的能量就可以合成一個僅含有一個正峰值的相關(guān)函數(shù)。文中給出了GFSA算法的實(shí)現(xiàn)環(huán)路結(jié)構(gòu)，對GFSA算法的跟蹤性能做了理論上的推導(dǎo)和基于Monte Carlo的仿真分析。仿真分析表明，針對BOC(n,n)信號，在相同積分時間，碼間距和累加次數(shù)的情況下，GFSA算法在跟蹤階段與傳統(tǒng)跟蹤環(huán)路相比依然有性能退化現(xiàn)象。在選通脈寬為1個碼片時，最大僅有2.1分貝的性能退化。隨著選通脈寬的減小，性能退化越來越不明顯，在0.5個碼片寬度和碼間距為0.2個碼片條件下僅有1分貝的性能退化，且退化的絕對值相對于傳統(tǒng)跟蹤算法非常小。所以，GFSA算法在消除BOC信號同步模糊性的同時利用窄選通函數(shù)可以獲得很好的跟蹤特性。由于濾波效應(yīng)，采用窄脈寬選通函數(shù)是切實(shí)可行的。另外，由于設(shè)計(jì)的跟蹤環(huán)路不再需要子載波生成電路，所以它簡單易行。 提出了適合BOC(n,n)和MBOC的BPST(BOC-PRN shifting technique)非模糊性同步算法：BPST算法的基本思想是利用接收到的BOC信號與本地PRN碼的互相關(guān)函數(shù)來合成一個具有非模糊特性的相關(guān)函數(shù)。BPST算法的接收機(jī)采用相同的結(jié)構(gòu)和不同延時的PRN序列就可以接收正弦或余弦BOC信號。對BPST算法的捕獲和跟蹤性能做了理論上的推導(dǎo)和基于Monte Carlo的仿真分析。理論和仿真分析表明，對中長距離的多徑干擾信號有極強(qiáng)的抑制能力。盡管BPST算法，在相同積分時間，碼間距和累加次數(shù)的情況下，在捕獲和跟蹤階段分別有0.5分貝和2.2分貝的性能損失，但它徹底解決了同步的模糊性問題。同其它非模糊性算法相比，性能相差無幾。因此，對sinBOC(n,n), cosBOC(n,n)和MBOC信號接收機(jī)來講采用BPST算法不失為一個很好的同步解決方案。 本文最大的成果就是提出了BOC信號捕獲和跟蹤環(huán)路及接收機(jī)實(shí)現(xiàn)結(jié)構(gòu)，以使現(xiàn)在實(shí)用的和計(jì)劃準(zhǔn)備使用GNSS接收信號的使用者可以獲得更好的定位服務(wù)。
[Abstract]:In modern navigation systems, the use of BOC modulation signals enables the sharing of spectrum between the navigation systems, and it is possible to improve the positioning accuracy and the ability to resist multipath interference. However, the synchronization ambiguity caused by the BOC signal subcarrier modulation is the key hot question to be solved urgently. Because of the multiple peak characteristics of the autocorrelation function of the BOC signal The synchronization algorithm used for BPSK signals is no longer applicable. Based on the in-depth study of the characteristics of the BOC modulation signal and the traditional synchronization scheme, three algorithms to solve the synchronization ambiguity are proposed.
A non fuzzy synchronization algorithm for SPART (Symmetrical Pulse Ambiguity Removing technique) is proposed. The principle of the algorithm is to construct two local BOC-like signals, one is even symmetric and the other is a singly symmetric signal. By synthesizing the cross correlation functions of the two local signals and BOC signals, the non fuzzy phase is obtained. The correlation function contains only a positive correlation peak, and all the adjacent peaks are eliminated, which ingeniously eliminates the potential threat to the acquisition and tracking of the side peaks. Not only is the implementation loop structure of the SPART algorithm, but also the simulation analysis based on the Monte Carlo and the SPAR based hardware platform based on the FPGA The validity of the T algorithm is verified. A theoretical deduction is made for the expression of the capture detection probability and the standard deviation of the tracking standard. The simulation shows that the SPART algorithm is not only suitable for sinusoidal BOC signal, but also suitable for the cosine BOC signal, but for the cosine BOC signal, the pulse width of the local signal used by the SPART algorithm is half the pulse width of the sinusoidal BOC signal. Compared with the traditional synchronization algorithm, the.SPART algorithm shows that in the case of the same integration time, the code spacing and the number of accumulations, the SPART algorithm has little performance degradation compared with the traditional tracking loop for the BOC signal with low modulation coefficient. The higher the modulation coefficient, the worse the BOC signal degradation. But don't forget the SPART. The original intention of the algorithm is to eliminate the positive side peaks in the autocorrelation function of the BOC signal in order to avoid capturing the side peaks and locking to the wrong phase detector zero. In addition, in order to compensate for the performance degradation of the SPART algorithm, we can increase the performance of the algorithm by increasing the coherence time, increasing the incoherent accumulating times and reducing the spacing of the small code.
A GFSA (Gating function Shifting Algorithm) non fuzzy algorithm suitable for BOC (n, n) and MBOC signals is proposed. The principle of the algorithm is to construct a gated pulse signal to modulate the local PRN code and subcarrier signal. The modulated local signal is interrelated with the received BOC, and the correlation function is shifted left and right to the left and right. Two correlation functions, when the pulse width of the elected pass function is within the range of [0.51] codes, the energy minus the energy can be reduced to a correlation function that contains only one positive peak. The implementation loop structure of the GFSA algorithm is given in this paper, which can be derived theoretically and based on the Monte Carlo based on the GFSA algorithm. Simulation analysis shows that, for the BOC (n, n) signal, the GFSA algorithm still has the performance degradation phenomenon compared with the traditional tracking loop at the same integration time, the code spacing and the number of accumulative times. The performance degradation is only 2.1 dB when the pulse width is 1 codes, and the performance is reduced with the decrease of the gating pulse width. It is becoming less and more obvious that only 1 decibels are degraded under the condition of 0.5 chip width and code spacing of 0.2 codes, and the absolute value of degradation is very small compared with the traditional tracking algorithm. Therefore, the GFSA algorithm can obtain good tracking characteristics by using narrow pass function while eliminating synchronization ambiguity of BOC signals. The narrow pulse width gating function is feasible. Moreover, since the tracking loop is no longer needed for the subcarrier generation circuit, it is simple and feasible.
A BPST (BOC-PRN shifting technique) non fuzzy synchronization algorithm suitable for BOC (n, n) and MBOC is proposed. The basic idea of BPST algorithm is to use the intercorrelation function of the received BOC signal and the local PRN code to synthesize a receiver with a non fuzzy correlation function.BPST algorithm using the same structure and different delay sequence. A sine or cosine BOC signal can be received. The acquisition and tracking performance of the BPST algorithm is theoretically derived and the simulation analysis based on Monte Carlo is made. The theoretical and simulation analysis shows that the medium and long distance multipath interference signals have a very strong suppression ability. Although the BPST algorithm is at the same integration time, the distance between the code and the number of accumulations In the capture and tracking phase, the performance loss of 0.5 dB and 2.2 DB respectively, but it completely solves the problem of synchronization fuzziness. Compared with other non fuzzy algorithms, the performance is very different. Therefore, it is a good synchronization solution for sinBOC (n, n), cosBOC (n, n) and MBOC signal receivers to adopt BPST algorithm.
The greatest achievement of this article is the proposed BOC signal capture and tracking loop and the receiver implementation structure, so that the users who are now practical and plan to use the GNSS receiving signal can get better positioning service.

【學(xué)位授予單位】：上海交通大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TN911.3

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 ;TD-AltBOC:A new COMPASS B2 modulation[J];Science China(Physics,Mechanics & Astronomy);2011年06期

本文編號：1796160