基于硬件的等光频间隔采样及频谱分析方法
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摘要
提出一种基于硬件的等光频间隔采样消除调频连续波(FMCW)激光测距系统调频非线性的改进措施。改进后的等光频间隔采样通过硬件数据采集即可一步实现,无需再进行后续繁杂的软件处理过程,极大地节省了内存空间和数据处理时间,并且较之基于软件的等光频间隔重采样方法采样位置更准确。研究了调频非线性对调频连续波激光测距系统测距精度的影响以及等光频间隔采样消除调频非线性的原理。在此基础上,针对等光频间隔采样方法在时域上为非均匀采样,传统频谱分析方法不再适用的问题,对其进行新的频谱分析,并推导出了重采样之后频谱峰值频率计算公式以及测距系统的距离求取公式,通过仿真验证了新的频谱分析公式的正确性。实验结果表明,基于硬件的等光频间隔采样方法比基于软件的等光频间隔重采样方法更简单并且具有更好的非线性消除效果、更高的测距分辨力和稳定性。
An improved nonlinearity correction algorithm by hardware-based equispaced-phase resampling for frequency modulated continuous wave(FMCW)ranging system was proposed.After improvement,equispaced-phase resampling method could be realized in one step by hardware data acquisition.No subsequent complex data processing is needed any more,which will save much memory space and data processing time.Moreover,compared with software-based equispaced-phase resampling method,the improved method had higher sampling accuracy.The effect of nonlinear frequency modulation on ranging precision of FMCW ranging system and the principle of equispaced-phase resampling for nonlinearity correction were explored.On this basis,a new spectral analysis method was presented for the reason that the equispaced-phase resampled data was not equally spaced in time domain and the traditional spectral analysis method is no longer applicable.The computational formulas of peak spectral frequency and object distance were deduced.Their correctness was verified by simulation.Experimental results show that equispaced-phase resampling based on hardware has higher ranging precision and resolution than equispaced-phase resampling based on software,and the former is simpler.
An improved nonlinearity correction algorithm by hardware-based equispaced-phase resampling for frequency modulated continuous wave(FMCW)ranging system was proposed.After improvement,equispaced-phase resampling method could be realized in one step by hardware data acquisition.No subsequent complex data processing is needed any more,which will save much memory space and data processing time.Moreover,compared with software-based equispaced-phase resampling method,the improved method had higher sampling accuracy.The effect of nonlinear frequency modulation on ranging precision of FMCW ranging system and the principle of equispaced-phase resampling for nonlinearity correction were explored.On this basis,a new spectral analysis method was presented for the reason that the equispaced-phase resampled data was not equally spaced in time domain and the traditional spectral analysis method is no longer applicable.The computational formulas of peak spectral frequency and object distance were deduced.Their correctness was verified by simulation.Experimental results show that equispaced-phase resampling based on hardware has higher ranging precision and resolution than equispaced-phase resampling based on software,and the former is simpler.
引文
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10 Vossiek M,Heide P,Nalezinski M,et al.Novel FMCW radar system concept with adaptive compensation of phase errors[C].26th European Microwave Conference,1996:135-139.
11 Wang Y,Li Q S,Gan D Y,et al.Research on nonlinearity correction imaging algorithm of FMCW SAR[C].2nd International Conference on Signal Processing Systems,2010:425-429.
12 Shi Guang,Zhang Fumin,Qu Xinghua,et al.Absolute distance measurement by high resolution frequency modulated continuous wave laser[J].Acta Physica Sinica,2014,63(18):184209.时光,张福民,曲兴华,等.高分辨率调频连续波激光绝对测距研究[J].物理学报,2014,63(18):184209.
13 Meng Xiangsong,Zhang Fumin,Qu Xinghua,et al.High precision and fast method for absolute distance measurement based on resampling technique used in FM continuous wave laser ranging[J].Acta Physica Sinica,2015,64(23):230601.孟祥松,张福民,曲兴华.基于重采样技术的调频连续波激光绝对测距高精度及快速测量方法研究[J].物理学报,2015,64(23):230601.
14 Meng X S,Zhang F M,Qu X H.Optimization of the signal processing in frequency modulated continuous wave laser ranging system[C].SPIE,2015,9446:94461Q.
15 Meta A,Hoogeboom P,Ligthart L P.Range non-linearities correction in FMCW SAR[C].IEEE International Conference on Geoscience and Remote Sensing Symposium,2006:403-406.
16 Yan Qingxu,Chen Zhaodou,Liu Huifang.On the applications of Weierstrass approximation theorem[J].Mathematics in Practice and Theory,2004,34(8):174-176.阎庆旭,陈兆斗,刘慧芳.Weierstrass逼近定理的应用[J].数学的实践与认识,2004,34(8):174-176.
17程佩青.数字信号处理教程[M].北京:清华大学出版社,2007.
2 Tan Shuo,Guo Wei.Research of short-distance target range detection system[J].Ship Electronic Engineering,2007,27(4):95-99.谭朔,郭伟.调频连续波近程测距系统研究[J].舰船电子工程,2007,27(4):95-99.
3 Qu Xinghua,Zhi Guangtao,Zhang Fumin,et al.Improvement of resolution of frequency modulated continuous wave laser ranging system by signal splicing[J].Optics and Precision Engineering,2015,23(1):40-47.曲兴华,职广涛,张福民,等.利用信号拼接提高调频连续波激光测距系统的分辨力[J].光学精密工程,2015,23(1):40-47.
4 Brennan P V,Huang Y,Ash M,et al.Determination of sweep linearity requirements in FMCW radar systems based on simple voltage-controlled oscillator sources[J].IEEE Transactions on Aerospace Electronic Systems,2011,47(3):1594-1604.
5 Meta A,Hoogeboom P,Ligthart L P.Signal processing for FMCW SAR[J].IEEE Transactions on Geoscience and Remote Sensing,2007,45(11):3519-3532.
6 Anghel A,Vasile G,Cacoveanu R,et al.Nonlinearity correction algorithm for wideband FMCW radars[C].European Signal Processing Conference,2013.
7 Scheiblhofer S,Schuster S,Stelzer A.High-speed FMCW radar frequency synthesizer with DDS based linearization[J].IEEE Microwave and Wireless Components Letters,2007,17(5):397-399.
8 Liu Kangkang,Liu Hongli,Zhao Ruchen,et al.Enhancement of tenability and stability of a continuous wave deep ultraviolet laser by feed-forward control method[J].Chinese J Lasers,2014,41(12):1202004.刘亢亢,刘洪力,赵儒臣,等.用前馈控制方法提高连续紫外激光器的调谐性和稳定性[J].中国激光,2014,41(12):1202004.
9 Wu Ying,Chen Dijun,Sun Yanguang,et al.Research on optical chirp linearization technique of semiconductor lasers by an optoelectronic feedback loop[J].Chinese J Lasers,2013,40(9):0902001.吴映,陈迪俊,孙延光,等.半导体激光器光电负反馈线性调频技术研究[J].中国激光,2013,40(9):0902001.
10 Vossiek M,Heide P,Nalezinski M,et al.Novel FMCW radar system concept with adaptive compensation of phase errors[C].26th European Microwave Conference,1996:135-139.
11 Wang Y,Li Q S,Gan D Y,et al.Research on nonlinearity correction imaging algorithm of FMCW SAR[C].2nd International Conference on Signal Processing Systems,2010:425-429.
12 Shi Guang,Zhang Fumin,Qu Xinghua,et al.Absolute distance measurement by high resolution frequency modulated continuous wave laser[J].Acta Physica Sinica,2014,63(18):184209.时光,张福民,曲兴华,等.高分辨率调频连续波激光绝对测距研究[J].物理学报,2014,63(18):184209.
13 Meng Xiangsong,Zhang Fumin,Qu Xinghua,et al.High precision and fast method for absolute distance measurement based on resampling technique used in FM continuous wave laser ranging[J].Acta Physica Sinica,2015,64(23):230601.孟祥松,张福民,曲兴华.基于重采样技术的调频连续波激光绝对测距高精度及快速测量方法研究[J].物理学报,2015,64(23):230601.
14 Meng X S,Zhang F M,Qu X H.Optimization of the signal processing in frequency modulated continuous wave laser ranging system[C].SPIE,2015,9446:94461Q.
15 Meta A,Hoogeboom P,Ligthart L P.Range non-linearities correction in FMCW SAR[C].IEEE International Conference on Geoscience and Remote Sensing Symposium,2006:403-406.
16 Yan Qingxu,Chen Zhaodou,Liu Huifang.On the applications of Weierstrass approximation theorem[J].Mathematics in Practice and Theory,2004,34(8):174-176.阎庆旭,陈兆斗,刘慧芳.Weierstrass逼近定理的应用[J].数学的实践与认识,2004,34(8):174-176.
17程佩青.数字信号处理教程[M].北京:清华大学出版社,2007.