Gm-APD脈沖累積激光雷達(dá)探測(cè)性能提高的研究
發(fā)布時(shí)間：2018-11-18 08:23
【摘要】：激光雷達(dá)具有測(cè)距精度高、角分辨率高、方向性好、抗干擾能力強(qiáng)的優(yōu)點(diǎn),廣泛應(yīng)用于三維遙感測(cè)繪、交會(huì)對(duì)接、導(dǎo)彈制導(dǎo)、自動(dòng)駕駛等領(lǐng)域。Gm-APD(Geiger-mode Avalanche Photodiode)作為激光雷達(dá)的探測(cè)器,具有單光子靈敏度和亞皮秒量級(jí)的時(shí)間分辨率,在遠(yuǎn)距離、弱信號(hào)的高精度探測(cè)中具有重大應(yīng)用價(jià)值。但是,Gm-APD只能探測(cè)信號(hào)的有和無,是一種數(shù)字探測(cè)技術(shù),無法直接響應(yīng)信號(hào)的強(qiáng)度信息。通過Gm-APD累積探測(cè)提出了一種精確的強(qiáng)度信息表征方法。建立了Gm-APD的泊松概率探測(cè)模型,采用時(shí)間分離區(qū)間的統(tǒng)計(jì)方法,得到了Gm-APD在任意一個(gè)子區(qū)間產(chǎn)生雪崩擊穿效應(yīng)的概率;通過累積探測(cè)的雪崩概率逆推得到平均信號(hào)光電子數(shù)精確表征目標(biāo)的強(qiáng)度信息,并且,理論研究了最佳信號(hào)強(qiáng)度探測(cè)區(qū)間;最后,設(shè)計(jì)并完成了Gm-APD激光雷達(dá)累積探測(cè)獲取高精度強(qiáng)度信息的實(shí)驗(yàn),相對(duì)強(qiáng)度測(cè)量誤差小于3%。當(dāng)平均信號(hào)光電子數(shù)大于4時(shí),可以采用衰減片同比衰減信號(hào)和噪聲,在保證Gm-APD對(duì)于信號(hào)的雪崩概率飽和輸出的同時(shí),進(jìn)一步衰減噪聲,從而提高Gm-APD激光雷達(dá)的探測(cè)性能。理論分析了Gm-APD激光雷達(dá)窄脈沖少次累積探測(cè)半閾值法的探測(cè)概率、虛警概率和測(cè)距精度,研究了衰減片透過率對(duì)探測(cè)性能的影響,最后利用距離像成像仿真進(jìn)行驗(yàn)證。實(shí)驗(yàn)設(shè)計(jì)了一個(gè)寬脈沖累積探測(cè)Gm-APD激光雷達(dá)系統(tǒng),在極強(qiáng)背景噪聲條件下,采用50 d B衰減片組將原本完全淹沒在噪聲中的信號(hào)光子計(jì)數(shù)分布圖完美提取。Gm-APD激光雷達(dá)在脈沖測(cè)距過程中存在距離漂移誤差,該漂移誤差與信號(hào)的強(qiáng)度有關(guān),隨著信號(hào)的增強(qiáng)而變大,隨著脈沖寬度的增大而增大。為了解決該距離漂移誤差產(chǎn)生的不良影響,分別提出了Gm-APD激光雷達(dá)寬脈沖累積探測(cè)的信號(hào)復(fù)原—雙高斯擬合法和信號(hào)復(fù)原—質(zhì)心算法去抑制距離漂移誤差。利用Gm-APD激光雷達(dá)的泊松雪崩概率模型,根據(jù)信號(hào)光子計(jì)數(shù)分布圖獲取信號(hào)光電子數(shù)分布圖。第一種方法采用雙高斯擬合的方法找到峰值位置,并將峰值位置作為目標(biāo)的距離信息。第二種方法采用質(zhì)心算法去尋找信號(hào)波形的質(zhì)心位置,并將質(zhì)心位置作為目標(biāo)的距離信息。兩種方法都能獲取目標(biāo)的高精度強(qiáng)度信息和距離信息。第一種方法的測(cè)距精度為1.2 cm,強(qiáng)度測(cè)量精度小于0.015個(gè)光電子;第二種方法的測(cè)距精度為0.6 cm,強(qiáng)度測(cè)量相對(duì)精度小于3%。不同材質(zhì)的物體對(duì)同一偏振光將會(huì)表現(xiàn)出不同的退偏特性,偏振探測(cè)可以獲得普通的強(qiáng)度探測(cè)無法獲得的額外信息。分析了偏振傳輸?shù)哪吕站仃嚤硎?利用薄透明物體前后表面的不同偏振特性,設(shè)計(jì)了一個(gè)雙Gm-APD偏振激光雷達(dá)系統(tǒng),獲取了薄透明物體前后表面的高精度距離信息。完成了10 cm厚度的水缸測(cè)量,測(cè)量精度小于1.1 cm。根據(jù)一種斯托克斯參量分振幅測(cè)量系統(tǒng)設(shè)計(jì)了一個(gè)四Gm-APD偏振激光雷達(dá)系統(tǒng),通過比對(duì)四路強(qiáng)度像的差異性,實(shí)驗(yàn)完成了光子量級(jí)條件下的極微弱信號(hào)的不同材質(zhì)目標(biāo)的鑒別。同時(shí)得到目標(biāo)的高精度距離像,測(cè)距精度小于0.8 cm。
[Abstract]:The laser radar has the advantages of high ranging precision, high angular resolution, good directivity and strong anti-interference ability, and is widely applied to the fields of three-dimensional remote sensing mapping, rendezvous and docking, missile guidance, automatic driving and the like. Gm-APD (Geiger-mode Avalanche Photodiode), as a detector for laser radar, has a time resolution on the order of single-photon sensitivity and sub-picosecond, and has great application value in high-precision detection of long-range and weak signals. However, the Gm-APD can only detect the presence and absence of the signal, and it is a digital detection technique that can't directly respond to the strength information of the signal. An accurate method of strength information representation is proposed by the accumulation of Gm-APD. based on the statistical method of the time separation interval, the probability of an avalanche breakdown effect generated by the Gm-APD in any one sub-interval is obtained; the intensity information of the target is accurately characterized by the inverse of the avalanche probability of the accumulated detection, In this paper, the best signal strength detection interval is studied. Finally, the experiment of obtaining the high-precision intensity information by the accumulative detection of the Gm-APD laser radar is designed and completed. The relative intensity measurement error is less than 3%. When the number of the average signal photoelectrons is greater than 4, the signal and the noise of the attenuation sheet can be attenuated on the same time, and the noise can be further attenuated while ensuring the saturation output of the avalanche probability of the Gm-APD for the signal, thereby improving the detection performance of the Gm-APD laser radar. In this paper, the detection probability, the false alarm probability and the ranging precision of the narrow-pulse low-pass cumulative detection half-threshold method of the Gm-APD laser radar are analyzed, and the influence of the transmission rate of the attenuation sheet on the detection performance is studied. Finally, the distance image imaging simulation is used for verification. A wide-pulse accumulative probe Gm-APD laser radar system is designed. Under the condition of very strong background noise, the signal photon counting profile which is completely inundated in the noise is extracted perfectly with the 50d B attenuation slice group. The Gm-APD laser radar has a distance drift error in the process of pulse ranging, and the drift error is related to the intensity of the signal, and increases with the increase of the pulse width as the signal is enhanced. In order to solve the adverse effects of the distance drift error, a signal recovery, dual-Gaussian quasi-legal and signal-recovery centroid algorithm of the Gm-APD laser radar wide pulse accumulation detection is proposed to suppress the distance drift error, respectively. The electron number distribution diagram of the signal is obtained from the signal photon counting distribution map by using the probability model of the Poisson avalanche of the Gm-APD laser radar. The first method uses a double-Gaussian fitting method to find the peak position and the peak position as the target distance information. the second method uses the centroid algorithm to find the centroid position of the signal waveform and to use the centroid position as the distance information of the target. Both methods can obtain high-precision intensity information and distance information of the target. The measurement accuracy of the first method is 1. 2cm, the accuracy of the intensity measurement is less than 0.015 photoelectrons, the range accuracy of the second method is 0.6 cm, and the relative accuracy of the intensity measurement is less than 3%. the different materials of the object will exhibit different depolarization characteristics for the same polarized light, and the polarization detection can obtain additional information which can not be obtained by ordinary intensity detection. In this paper, a double-Gm-APD polarization laser radar system is designed by using the different polarization characteristics of the front and back surfaces of a thin transparent object, and the high-precision distance information of the front and rear surfaces of the thin transparent object is obtained. The water cylinder with a thickness of 10 cm was measured and the measurement accuracy was less than 1. 1 cm. In this paper, a four-Gm-APD polarization laser radar system is designed according to a Stokes parameter partial-amplitude measurement system. By comparing the difference of the four-way intensity image, the identification of different material targets of extremely weak signals under the order of photon magnitude is completed. and the high-precision distance image of the target is obtained at the same time, and the ranging precision is less than 0.8 cm.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：TN958.98
本文編號(hào)：2339459
[Abstract]:The laser radar has the advantages of high ranging precision, high angular resolution, good directivity and strong anti-interference ability, and is widely applied to the fields of three-dimensional remote sensing mapping, rendezvous and docking, missile guidance, automatic driving and the like. Gm-APD (Geiger-mode Avalanche Photodiode), as a detector for laser radar, has a time resolution on the order of single-photon sensitivity and sub-picosecond, and has great application value in high-precision detection of long-range and weak signals. However, the Gm-APD can only detect the presence and absence of the signal, and it is a digital detection technique that can't directly respond to the strength information of the signal. An accurate method of strength information representation is proposed by the accumulation of Gm-APD. based on the statistical method of the time separation interval, the probability of an avalanche breakdown effect generated by the Gm-APD in any one sub-interval is obtained; the intensity information of the target is accurately characterized by the inverse of the avalanche probability of the accumulated detection, In this paper, the best signal strength detection interval is studied. Finally, the experiment of obtaining the high-precision intensity information by the accumulative detection of the Gm-APD laser radar is designed and completed. The relative intensity measurement error is less than 3%. When the number of the average signal photoelectrons is greater than 4, the signal and the noise of the attenuation sheet can be attenuated on the same time, and the noise can be further attenuated while ensuring the saturation output of the avalanche probability of the Gm-APD for the signal, thereby improving the detection performance of the Gm-APD laser radar. In this paper, the detection probability, the false alarm probability and the ranging precision of the narrow-pulse low-pass cumulative detection half-threshold method of the Gm-APD laser radar are analyzed, and the influence of the transmission rate of the attenuation sheet on the detection performance is studied. Finally, the distance image imaging simulation is used for verification. A wide-pulse accumulative probe Gm-APD laser radar system is designed. Under the condition of very strong background noise, the signal photon counting profile which is completely inundated in the noise is extracted perfectly with the 50d B attenuation slice group. The Gm-APD laser radar has a distance drift error in the process of pulse ranging, and the drift error is related to the intensity of the signal, and increases with the increase of the pulse width as the signal is enhanced. In order to solve the adverse effects of the distance drift error, a signal recovery, dual-Gaussian quasi-legal and signal-recovery centroid algorithm of the Gm-APD laser radar wide pulse accumulation detection is proposed to suppress the distance drift error, respectively. The electron number distribution diagram of the signal is obtained from the signal photon counting distribution map by using the probability model of the Poisson avalanche of the Gm-APD laser radar. The first method uses a double-Gaussian fitting method to find the peak position and the peak position as the target distance information. the second method uses the centroid algorithm to find the centroid position of the signal waveform and to use the centroid position as the distance information of the target. Both methods can obtain high-precision intensity information and distance information of the target. The measurement accuracy of the first method is 1. 2cm, the accuracy of the intensity measurement is less than 0.015 photoelectrons, the range accuracy of the second method is 0.6 cm, and the relative accuracy of the intensity measurement is less than 3%. the different materials of the object will exhibit different depolarization characteristics for the same polarized light, and the polarization detection can obtain additional information which can not be obtained by ordinary intensity detection. In this paper, a double-Gm-APD polarization laser radar system is designed by using the different polarization characteristics of the front and back surfaces of a thin transparent object, and the high-precision distance information of the front and rear surfaces of the thin transparent object is obtained. The water cylinder with a thickness of 10 cm was measured and the measurement accuracy was less than 1. 1 cm. In this paper, a four-Gm-APD polarization laser radar system is designed according to a Stokes parameter partial-amplitude measurement system. By comparing the difference of the four-way intensity image, the identification of different material targets of extremely weak signals under the order of photon magnitude is completed. and the high-precision distance image of the target is obtained at the same time, and the ranging precision is less than 0.8 cm.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：TN958.98
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相關(guān)期刊論文 前3條
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3 徐璐;張宇;張勇;趙遠(yuǎn);;蓋革模式雪崩光電二極管激光雷達(dá)累積探測(cè)性能的研究[J];中國(guó)激光;2012年04期
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