Gm-APD脉冲累积激光雷达探测性能提高的研究
发布时间：2018-11-18 08:23
【摘要】：激光雷达具有测距精度高、角分辨率高、方向性好、抗干扰能力强的优点,广泛应用于三维遥感测绘、交会对接、导弹制导、自动驾驶等领域。Gm-APD(Geiger-mode Avalanche Photodiode)作为激光雷达的探测器,具有单光子灵敏度和亚皮秒量级的时间分辨率,在远距离、弱信号的高精度探测中具有重大应用价值。但是,Gm-APD只能探测信号的有和无,是一种数字探测技术,无法直接响应信号的强度信息。通过Gm-APD累积探测提出了一种精确的强度信息表征方法。建立了Gm-APD的泊松概率探测模型,采用时间分离区间的统计方法,得到了Gm-APD在任意一个子区间产生雪崩击穿效应的概率;通过累积探测的雪崩概率逆推得到平均信号光电子数精确表征目标的强度信息,并且,理论研究了最佳信号强度探测区间;最后,设计并完成了Gm-APD激光雷达累积探测获取高精度强度信息的实验,相对强度测量误差小于3%。当平均信号光电子数大于4时,可以采用衰减片同比衰减信号和噪声,在保证Gm-APD对于信号的雪崩概率饱和输出的同时,进一步衰减噪声,从而提高Gm-APD激光雷达的探测性能。理论分析了Gm-APD激光雷达窄脉冲少次累积探测半阈值法的探测概率、虚警概率和测距精度,研究了衰减片透过率对探测性能的影响,最后利用距离像成像仿真进行验证。实验设计了一个宽脉冲累积探测Gm-APD激光雷达系统,在极强背景噪声条件下,采用50 d B衰减片组将原本完全淹没在噪声中的信号光子计数分布图完美提取。Gm-APD激光雷达在脉冲测距过程中存在距离漂移误差,该漂移误差与信号的强度有关,随着信号的增强而变大,随着脉冲宽度的增大而增大。为了解决该距离漂移误差产生的不良影响,分别提出了Gm-APD激光雷达宽脉冲累积探测的信号复原—双高斯拟合法和信号复原—质心算法去抑制距离漂移误差。利用Gm-APD激光雷达的泊松雪崩概率模型,根据信号光子计数分布图获取信号光电子数分布图。第一种方法采用双高斯拟合的方法找到峰值位置,并将峰值位置作为目标的距离信息。第二种方法采用质心算法去寻找信号波形的质心位置,并将质心位置作为目标的距离信息。两种方法都能获取目标的高精度强度信息和距离信息。第一种方法的测距精度为1.2 cm,强度测量精度小于0.015个光电子;第二种方法的测距精度为0.6 cm,强度测量相对精度小于3%。不同材质的物体对同一偏振光将会表现出不同的退偏特性,偏振探测可以获得普通的强度探测无法获得的额外信息。分析了偏振传输的穆勒矩阵表示,利用薄透明物体前后表面的不同偏振特性,设计了一个双Gm-APD偏振激光雷达系统,获取了薄透明物体前后表面的高精度距离信息。完成了10 cm厚度的水缸测量,测量精度小于1.1 cm。根据一种斯托克斯参量分振幅测量系统设计了一个四Gm-APD偏振激光雷达系统,通过比对四路强度像的差异性,实验完成了光子量级条件下的极微弱信号的不同材质目标的鉴别。同时得到目标的高精度距离像,测距精度小于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.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TN958.98
本文编号：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.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TN958.98
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相关期刊论文 前3条
1 孙剑峰;姜鹏;张秀川;周鑫;付宏明;高新江;王骐;;32×32面阵InGaAs Gm-APD激光主动成像实验[J];红外与激光工程;2016年12期
2 罗远;贺岩;耿立明;王明建;雷琳君;吴姚芳;胡善江;侯霞;陈卫标;;基于光子计数技术的远程测距激光雷达[J];中国激光;2016年05期
3 徐璐;张宇;张勇;赵远;;盖革模式雪崩光电二极管激光雷达累积探测性能的研究[J];中国激光;2012年04期
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