基于Golomb序列调制的目标距离速度测量方法

针对连续波激光雷达在同步测量目标距离和速度的应用中存在辐射信号上限峰值功率低、测量极限距离近的问题，提出一种基于Golomb脉冲序列调制的测量信号波形，研究该方法在道路环境中同步测量目标距离和速度的可行性。首先，以一种准连续波，即伪随机（PN）码调制为例分析连续波调制方法存在的发射信号峰值功率低的问题，在此基础上讨论Golomb序列的特征，提出使用Golomb序列调制发射信号提高发射脉冲峰值功率的方法；然后，讨论Golomb序列调制的多普勒信号频谱分析方法和基于数据累加的延迟时间定位方法，实现同步测量目标的速度和距离；最后，在道路目标产生的多普勒频率范围内，通过仿真实验验证该方法的正确性。实验结果表明，在以脉冲序列构成的对多普勒信号平均采样率远低于奈奎斯特频率的条件下，仍然可以通过快速傅里叶变换（FFT）方法获得多普勒信号的频率，从而在发射平均功率恒定的条件下极大提高单脉冲的峰值功率；另外，利用Golomb序列的不等间隔特性，通过数据累加方法可以完成对激光脉冲飞行时间的定位，在保证了速度测量的同时实现对目标距离的测量。

Target range and speed measurement method based on Golomb series modulation

In view of the problems that upper limit of radiated peak power is low for continuous wave laser radar, which limits the maximum measurement range in the application of range and speed measurement, a waveform of modulated signal based on Golomb series was proposed, and the feasibility of simultaneously measuring target's range and speed in road environments by the method was studied. Firstly, the problem of low transmitted signal peak power that exists in continuous wave modulating method was analyzed by using a quasi-continuous, i.e., Pseudo random Noise (PN) code modulation as an example. Characteristics of Golomb series were discussed, and a modulation method based on Golomb series was proposed for raising the peak power of transmitted pulse. Then, a method for analyzing spectrum of Doppler signal modulated by Golomb series was discussed, as well as a data accumulation method for locating signal delay time, such that range and speed could be measured simultaneously. Finally, within the range of Doppler frequency that is generated by moving road targets in road environment, simulations were performed to verify the correctness of the proposed method. The experimental results show that Fast Fourier Transform (FFT) can be used for obtaining the frequency of Doppler signal even when the sampling frequency provided by the pulse series is much lower than the Nyquist frequency, thus largely increasing the peak power of single pulse under the condition that average transmission power keeps unchanged. Furthermore, data accumulation method can be used for locating laser pulse flight time by exploiting the non-equal interval property of Golomb series, ensuring both target range measurement and speed measurement from the same signal.