地基寬帶分布式全相參雷達技術(shù)研究
發(fā)布時間：2018-09-14 12:38
【摘要】：為了增大雷達探測威力、提高雷達探測精度,通常采用增大雷達天線口徑的方式。而傳統(tǒng)大口徑雷達存在機動部署困難、戰(zhàn)場生存能力差、制造成本昂貴、對器件的工藝水平要求苛刻、后期難以維護等問題,這些問題極大地限制了其發(fā)展與應(yīng)用。為了克服傳統(tǒng)大孔徑雷達的固有缺陷,林肯實驗室提出了分布式全相參雷達的概念,該雷達通過對多部小孔徑單元雷達進行信號級的融合處理,使其在性能上等效于大孔徑雷達。目前,研究人員對分布式全相參雷達的研究還處于起步探索階段,實現(xiàn)該體制雷達的關(guān)鍵技術(shù)尚待解決。本文系統(tǒng)分析了分布式全相參雷達的結(jié)構(gòu)組成和工作流程;針對實現(xiàn)分布式寬帶全相參所面臨的關(guān)鍵問題,提出了基于正交信號和相參信號的相參參數(shù)估計方法、基于內(nèi)外定標的系統(tǒng)同步方法以及基于頻率步進信號的寬帶全相參方法;結(jié)合分布式系統(tǒng)多單元雷達的陣列結(jié)構(gòu),研究了一種對抗雷達主瓣干擾的有效方法。論文的主要研究內(nèi)容和成果如下:1、在分布式全相參雷達中,由于各單元雷達與目標的距離不同,導(dǎo)致各發(fā)射信號在目標處存在時間差和相位差,本文將這兩個參數(shù)合稱為相參參數(shù)。為了實現(xiàn)雷達的全相參工作,要求各單元雷達發(fā)射信號應(yīng)在目標處相參疊加,因此需要準確獲取相參參數(shù)。本文研究了相參參數(shù)的估計方法:首先,介紹了分布式全相參雷達的系統(tǒng)組成,詳細給出了其工作流程,并根據(jù)各單元雷達與目標的相對位置關(guān)系,建立了相參參數(shù)的數(shù)學(xué)模型;然后,對應(yīng)分布式系統(tǒng)的工作流程,分別提出了基于正交信號的相參參數(shù)估計方法和基于相參信號的相參參數(shù)估計方法,為了提高相參參數(shù)的估計精度,提出了基于修正代價函數(shù)的正交多相編碼信號的波形設(shè)計方法,并針對兩種信號的相參參數(shù),分別推導(dǎo)了其克拉美-羅下界(Cramer Rao Low Bound,CRLB),對兩種估計方法的估計性能進行了仿真分析;最后,為了對運動目標的相參參數(shù)進行有效地跟蹤,提出了基于Kalman的相參參數(shù)濾波方法,并通過仿真驗證了該方法的有效性。相參參數(shù)是實現(xiàn)分布式雷達全相參工作的關(guān)鍵參數(shù),通過對分布式雷達相參參數(shù)估計方法的研究,為實現(xiàn)系統(tǒng)全相參提供了技術(shù)支撐。2、分布式系統(tǒng)的時間和相位同步誤差將導(dǎo)致相參參數(shù)估計值存在偏差,進而降低系統(tǒng)的相參性能。本文針對分布式全相參雷達的系統(tǒng)同步問題,提出了基于內(nèi)、外定標的分布式系統(tǒng)時間同步和相位同步方法。首先,分析了系統(tǒng)同步誤差的來源,建立了時間同步誤差和相位同步誤差的數(shù)學(xué)模型,分析了同步誤差對系統(tǒng)相參性能的影響,在一定相參性能損失的前提下給出了分布式全相參雷達對時間同步誤差及相位同步誤差的指標要求;然后,在設(shè)計了系統(tǒng)本振同源方案的基礎(chǔ)上,提出了基于內(nèi)、外定標的系統(tǒng)時間同步和相位同步方法,即:采用中心站向各單元雷達分發(fā)信號的方式構(gòu)成各單元雷達的本振信號,以消除晶振源頻率準確度及穩(wěn)定度對同步誤差帶來的影響,在此基礎(chǔ)上,分別基于內(nèi)、外定標的方式對時間同步誤差和相位同步誤差進行估計,并利用同步誤差估計值對雷達發(fā)射信號進行補償以最終實現(xiàn)系統(tǒng)同步,仿真結(jié)果驗證了所提同步方法的有效性。系統(tǒng)同步是實現(xiàn)分布式雷達全相參工作的前提,通過對分布式全相參雷達系統(tǒng)同步方法的研究,為實現(xiàn)系統(tǒng)全相參奠定了基礎(chǔ)。3、為了適應(yīng)現(xiàn)代雷達對距離高分辨率的要求,需要對寬帶分布式全相參雷達進行研究。針對寬帶分布式系統(tǒng)中時間同步誤差會嚴重降低系統(tǒng)相參性能的問題,本文提出了基于頻率步進信號的寬帶全相參技術(shù),以提高系統(tǒng)對時間同步誤差的魯棒性。首先,基于頻率步進信號瞬時窄帶合成寬帶的特性,提出采用調(diào)頻步進信號代替?zhèn)鹘y(tǒng)線性調(diào)頻信號作為分布式全相參雷達的發(fā)射信號,能夠在保證寬帶雷達高測量性能的前提下提高分布式系統(tǒng)對時間同步誤差的魯棒性,從而降低寬帶分布式系統(tǒng)對時間同步精度的要求;然后,為了對分布式全相參雷達的相參性能進行定量分析,定義了發(fā)射相參效率和全相參效率。由于實際雷達系統(tǒng)工作時兩單元雷達回波信噪比不相同,進而導(dǎo)致原理想全相參回波信噪比計算方法不再適用,故分析推導(dǎo)了該場景下理想全相參回波信噪比的計算公式,并對應(yīng)給出了發(fā)射相參效率和全相參效率的計算方法;最后,為了對基于頻率步進信號的寬帶全相參技術(shù)進行實驗驗證,本文研制了分布式全相參雷達實驗系統(tǒng)原理樣機,利用實驗系統(tǒng)開展了基于調(diào)頻步進寬帶全相參暗室及外場實驗,并取得了良好的結(jié)果,從而在仿真驗證的基礎(chǔ)上,進一步利用實測數(shù)據(jù)證明了所提方法的有效性。寬帶雷達是現(xiàn)代雷達發(fā)展的必然趨勢,通過對寬帶分布式全相參技術(shù)的研究,為分布式系統(tǒng)的未來發(fā)展提供了技術(shù)支撐。4、針對雷達主瓣干擾這一難題,結(jié)合分布式系統(tǒng)多單元雷達的陣列結(jié)構(gòu),本文研究了基于大孔徑輔助接收陣列的主瓣干擾抑制方法,借助大孔徑陣列的空間高分辨率優(yōu)勢,利用輔助陣列接收的干擾數(shù)據(jù)對消主雷達的主瓣干擾。首先,針對輔助陣列均勻間隔的布陣方式,對輔助陣列總長度、陣列雷達間距及單元雷達個數(shù)進行了設(shè)計;然后,利用輔助陣列接收的干擾信號與主雷達接收的干擾信號之間的相關(guān)性,基于最小均方誤差(Minimum Mean Square Error,MMSE)準則和最大信干噪比(Maximum Signal to Interference plus Noise Ratio,MSINR)準則,分別提出了兩種抑制主瓣干擾的自適應(yīng)波束形成方法;此外,由于輔助陣列的均勻稀疏特性導(dǎo)致其陣列方向圖中存在較高的柵瓣,故采用非均勻間隔布陣的方式以降低柵瓣電平,并在最小單元雷達間距和最大陣列長度的限制條件下提出了基于修正遺傳算法的陣列間距設(shè)計方法,對輔助陣列間距進行了重新設(shè)計;最后,利用所提方法對含有干擾成分的雷達回波數(shù)據(jù)進行了處理,仿真驗證了所提方法的有效性。通過對分布式雷達對抗主瓣干擾技術(shù)的研究,擴展了分布式雷達系統(tǒng)的功能及應(yīng)用領(lǐng)域。
[Abstract]:In order to increase the detection power and improve the detection precision of radar, the method of enlarging the antenna aperture is usually adopted. However, the traditional large-aperture radar has some problems, such as difficult maneuvering deployment, poor battlefield survivability, high manufacturing cost, strict requirements for the technological level of the device, and difficult maintenance in the later period, which greatly restrict its development and development. Application. In order to overcome the inherent defects of traditional large aperture radar, Lincoln Laboratory put forward the concept of distributed all-coherent radar, which is equivalent to large aperture radar in performance by fusing several small aperture unit radars at signal level. In the initial exploration stage, the key technology to realize this radar system remains to be solved. This paper systematically analyzes the structure and work flow of distributed all-coherent radar, and proposes a coherent parameter estimation method based on orthogonal signal and coherent signal, and a system based on internal and external calibration. The main contents and achievements of this paper are as follows: 1. In distributed all-coherent radar, due to the different distances between the radar and the target, each unit has its own characteristics. In order to realize the coherent operation of the radar, it is necessary to obtain the coherent parameters accurately. This paper studies the estimation method of the coherent parameters. The system composition of distributed all-coherent radar is given in detail, and the mathematical model of coherent parameters is established according to the relative position relationship between each unit radar and target. Then, corresponding to the workflow of distributed system, the estimation method of coherent parameters based on orthogonal signals and the phase based on coherent signals are proposed respectively. In order to improve the estimation accuracy of coherent parameters, a waveform design method for orthogonal polyphase coded signals based on modified cost function is proposed. Cramer Rao Low Bound (CRLB) is derived for the coherent parameters of the two signals, and the estimation performance of the two methods is simulated. Finally, in order to track the coherent parameters of moving targets effectively, a Kalman-based filtering method of coherent parameters is proposed, and the effectiveness of this method is verified by simulation. Coherent parameters are the key parameters to realize the full coherent work of distributed radar, and the method of estimating the coherent parameters of distributed radar is studied. All-coherent system provides technical support. 2. The time and phase synchronization errors of distributed system will lead to the deviation of the estimation of coherent parameters, and then reduce the coherence performance of the system. Firstly, the source of system synchronization error is analyzed, the mathematical models of time synchronization error and phase synchronization error are established, the influence of synchronization error on system coherence is analyzed, and the index requirements of time synchronization error and phase synchronization error for distributed all-coherent radar are given under the premise of a certain loss of coherence performance. Then, based on the design of the system local oscillator homology scheme, a method of time synchronization and phase synchronization based on internal and external calibration is proposed, that is, the local oscillator signal of each unit radar is formed by the way that the central station distributes signals to each unit radar, so as to eliminate the influence of the frequency accuracy and stability of crystal oscillator on the synchronization error. On this basis, the time synchronization error and phase synchronization error are estimated based on internal and external calibration respectively, and the synchronization error estimation is used to compensate the radar transmitted signal to realize the system synchronization. The simulation results verify the effectiveness of the proposed synchronization method. The premise is that the research on the synchronization method of distributed all-coherent radar system lays a foundation for the realization of all-coherent radar system. 3. In order to meet the requirements of modern radar for high range and high resolution, it is necessary to study wideband distributed all-coherent radar. In order to improve the robustness of the system to the time synchronization error, a wideband all-coherent technique based on stepped-frequency signal is proposed. Firstly, based on the characteristics of instantaneous narrowband synthesis of stepped-frequency signal, stepped-frequency signal is proposed to replace the traditional linear frequency modulation signal as the transmitting signal of distributed all-coherent radar. It can improve the robustness of the distributed system to the time synchronization error while ensuring the high measurement performance of the wideband radar, so as to reduce the requirement of the time synchronization precision of the wideband distributed system. The difference of signal-to-noise ratio between two radar echoes in the operation of an international radar system leads to the inapplicability of the method for calculating the signal-to-noise ratio of the ideal fully coherent echoes in principle. Therefore, the formulas for calculating the signal-to-noise ratio of the ideal fully coherent echoes in this scenario are analyzed and deduced, and the methods for calculating the transmitting coherence efficiency and the total coherence efficiency are given correspondingly. Based on the wide-band all-coherent technology of stepped-frequency signal, the principle prototype of distributed all-coherent radar experimental system is developed. The experiments of wide-band all-coherent darkroom and outfield based on stepped-frequency modulation are carried out by using the experimental system, and good results are obtained. On the basis of simulation and verification, the measured data are further utilized. It is proved that the proposed method is effective. Broadband radar is the inevitable trend of modern radar development. Through the research of wideband distributed all-coherent technology, it provides technical support for the future development of distributed system. 4. Aiming at the problem of radar main lobe jamming, combined with the array structure of distributed system multi-unit radar, this paper studies based on The main lobe jamming suppression method of large aperture auxiliary receiving array is proposed. With the advantage of high spatial resolution of large aperture array, the main lobe jamming of the main radar is cancelled by the jamming data received by the auxiliary array. Firstly, the total length of the auxiliary array, the spacing of the array radar and the number of unit radars are calculated according to the uniform spacing of the auxiliary array. Then, based on the correlation between the jamming signal received by the auxiliary array and the jamming signal received by the main radar, two kinds of self-restraining methods for the main lobe jamming are proposed, respectively, based on the minimum mean square error (MMSE) criterion and the maximum signal to interference plus Noise Ratio (MSINR) criterion. In addition, due to the uniform sparse characteristic of the auxiliary array, there are high grating lobes in the array pattern, so the non-uniform spaced array is used to reduce the grating lobe level, and the array spacing based on the modified genetic algorithm is proposed under the restriction of the minimum element radar spacing and the maximum array length. Finally, the method is used to process the radar echo data with jamming components, and the effectiveness of the proposed method is verified by simulation. Through the research of distributed radar countering main lobe jamming technology, the functions and application fields of distributed radar system are extended.
【學(xué)位授予單位】：北京理工大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：TN957.51
本文編號：2242734
[Abstract]:In order to increase the detection power and improve the detection precision of radar, the method of enlarging the antenna aperture is usually adopted. However, the traditional large-aperture radar has some problems, such as difficult maneuvering deployment, poor battlefield survivability, high manufacturing cost, strict requirements for the technological level of the device, and difficult maintenance in the later period, which greatly restrict its development and development. Application. In order to overcome the inherent defects of traditional large aperture radar, Lincoln Laboratory put forward the concept of distributed all-coherent radar, which is equivalent to large aperture radar in performance by fusing several small aperture unit radars at signal level. In the initial exploration stage, the key technology to realize this radar system remains to be solved. This paper systematically analyzes the structure and work flow of distributed all-coherent radar, and proposes a coherent parameter estimation method based on orthogonal signal and coherent signal, and a system based on internal and external calibration. The main contents and achievements of this paper are as follows: 1. In distributed all-coherent radar, due to the different distances between the radar and the target, each unit has its own characteristics. In order to realize the coherent operation of the radar, it is necessary to obtain the coherent parameters accurately. This paper studies the estimation method of the coherent parameters. The system composition of distributed all-coherent radar is given in detail, and the mathematical model of coherent parameters is established according to the relative position relationship between each unit radar and target. Then, corresponding to the workflow of distributed system, the estimation method of coherent parameters based on orthogonal signals and the phase based on coherent signals are proposed respectively. In order to improve the estimation accuracy of coherent parameters, a waveform design method for orthogonal polyphase coded signals based on modified cost function is proposed. Cramer Rao Low Bound (CRLB) is derived for the coherent parameters of the two signals, and the estimation performance of the two methods is simulated. Finally, in order to track the coherent parameters of moving targets effectively, a Kalman-based filtering method of coherent parameters is proposed, and the effectiveness of this method is verified by simulation. Coherent parameters are the key parameters to realize the full coherent work of distributed radar, and the method of estimating the coherent parameters of distributed radar is studied. All-coherent system provides technical support. 2. The time and phase synchronization errors of distributed system will lead to the deviation of the estimation of coherent parameters, and then reduce the coherence performance of the system. Firstly, the source of system synchronization error is analyzed, the mathematical models of time synchronization error and phase synchronization error are established, the influence of synchronization error on system coherence is analyzed, and the index requirements of time synchronization error and phase synchronization error for distributed all-coherent radar are given under the premise of a certain loss of coherence performance. Then, based on the design of the system local oscillator homology scheme, a method of time synchronization and phase synchronization based on internal and external calibration is proposed, that is, the local oscillator signal of each unit radar is formed by the way that the central station distributes signals to each unit radar, so as to eliminate the influence of the frequency accuracy and stability of crystal oscillator on the synchronization error. On this basis, the time synchronization error and phase synchronization error are estimated based on internal and external calibration respectively, and the synchronization error estimation is used to compensate the radar transmitted signal to realize the system synchronization. The simulation results verify the effectiveness of the proposed synchronization method. The premise is that the research on the synchronization method of distributed all-coherent radar system lays a foundation for the realization of all-coherent radar system. 3. In order to meet the requirements of modern radar for high range and high resolution, it is necessary to study wideband distributed all-coherent radar. In order to improve the robustness of the system to the time synchronization error, a wideband all-coherent technique based on stepped-frequency signal is proposed. Firstly, based on the characteristics of instantaneous narrowband synthesis of stepped-frequency signal, stepped-frequency signal is proposed to replace the traditional linear frequency modulation signal as the transmitting signal of distributed all-coherent radar. It can improve the robustness of the distributed system to the time synchronization error while ensuring the high measurement performance of the wideband radar, so as to reduce the requirement of the time synchronization precision of the wideband distributed system. The difference of signal-to-noise ratio between two radar echoes in the operation of an international radar system leads to the inapplicability of the method for calculating the signal-to-noise ratio of the ideal fully coherent echoes in principle. Therefore, the formulas for calculating the signal-to-noise ratio of the ideal fully coherent echoes in this scenario are analyzed and deduced, and the methods for calculating the transmitting coherence efficiency and the total coherence efficiency are given correspondingly. Based on the wide-band all-coherent technology of stepped-frequency signal, the principle prototype of distributed all-coherent radar experimental system is developed. The experiments of wide-band all-coherent darkroom and outfield based on stepped-frequency modulation are carried out by using the experimental system, and good results are obtained. On the basis of simulation and verification, the measured data are further utilized. It is proved that the proposed method is effective. Broadband radar is the inevitable trend of modern radar development. Through the research of wideband distributed all-coherent technology, it provides technical support for the future development of distributed system. 4. Aiming at the problem of radar main lobe jamming, combined with the array structure of distributed system multi-unit radar, this paper studies based on The main lobe jamming suppression method of large aperture auxiliary receiving array is proposed. With the advantage of high spatial resolution of large aperture array, the main lobe jamming of the main radar is cancelled by the jamming data received by the auxiliary array. Firstly, the total length of the auxiliary array, the spacing of the array radar and the number of unit radars are calculated according to the uniform spacing of the auxiliary array. Then, based on the correlation between the jamming signal received by the auxiliary array and the jamming signal received by the main radar, two kinds of self-restraining methods for the main lobe jamming are proposed, respectively, based on the minimum mean square error (MMSE) criterion and the maximum signal to interference plus Noise Ratio (MSINR) criterion. In addition, due to the uniform sparse characteristic of the auxiliary array, there are high grating lobes in the array pattern, so the non-uniform spaced array is used to reduce the grating lobe level, and the array spacing based on the modified genetic algorithm is proposed under the restriction of the minimum element radar spacing and the maximum array length. Finally, the method is used to process the radar echo data with jamming components, and the effectiveness of the proposed method is verified by simulation. Through the research of distributed radar countering main lobe jamming technology, the functions and application fields of distributed radar system are extended.
【學(xué)位授予單位】：北京理工大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：TN957.51
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