SCIENTIA SINICA Informationis, Volume 47, Issue 1: 73-85(2017) https://doi.org/10.1360/N112015-00301

Nonlinearity correction of low cost UWB X-band LFMCW-SAR source}{Nonlinearity correction of low cost UWB X-band LFMCW-SAR source

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  • ReceivedJan 22, 2016
  • AcceptedFeb 26, 2016
  • PublishedOct 25, 2016


For the application of near range imaging with wideband LFMCW-SAR imaging, this paper presents a scheme to generate X-band signal with 5.1 GHz bandwidth based on a YIG oscillator. This method has a simple structure and low cost. However, it introduces a certain degree of nonlinearity, resulting in range-resolution degradation. Conventional nonlinearity estimation methods do not work well or fail with low SINR. To solve this problem, a two-step high order ambiguity function method, based on wide and narrow band filters, is used to estimate the nonlinear error. The nonlinearity is corrected by resampling. In the end, the nonlinear correction algorithm is validated with simulation data, delay-line data, and rail-SAR data.

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[1] Charvat G L, Kempel L C, Coleman C. A low-power high-sensitivity X-band rail SAR imaging system. IEEE Antennas Propag Mag, 2008, 50: 108-115. Google Scholar

[2] Charvat G. A low-power radar imaging system. Dissertation for Ph.D. Degree. East Lansing: Michigan State University, 2007. Google Scholar

[3] Koh G, Lever J H, Arcone S A, et al. Autonomous FMCW radar survey of Antarctic shear zone. In: Proceedings of the 13th International Conference on Ground Penetrating Radar, Lecce, 2010. 1-5. Google Scholar

[4] Fernandes J L. Millimeter-wave imaging of Person-Borne improvised explosive devices. Dissertation for Ph.D. Degree. Massachusetts: Northeastern University Boston, 2010. 3-8. Google Scholar

[5] Pohl N, Jacschke T, Vogt M. Ultra high resolution SAR imaging using an 80 GHz FMCW-radar with 25 GHz bandwidth. In: Proceedings of the 9th European Conference on Synthetic Aperture Radar, Nuremberg, 2012. 189-192. Google Scholar

[6] Jaeschke T, Vogt M, Baer C. et al. Improvements in distance measurement and SAR-imaging applications by using ultra-high resolution mm-wave FMCW radar systems. In: Proceedings of IEEE MTT-S International Microwave Symposium Digest, Montreal, 2012. 1-3. Google Scholar

[7] Yang S, Hao Y, Chang Y, et al. A 239-281 GHz Sub-THz imager with 100MHz resolution by CMOS direct-conversion receiver with on-chip circular-polarized SIW antenna. In: Proceedings of the IEEE Custom Integrated Circuits Conference, San Jose, 2014. 1-4. Google Scholar

[8] Yu Y, Pi Y M. Terahertz high-resolution radar clutter measurement and analysis. J Radars, 2015, 4: 217-221 [喻洋, 皮亦鸣. 太赫兹高分辨率雷达杂波测量与分析. 雷达学报, 2015, 4: 217-221]. Google Scholar

[9] Cai Y W, Yang C, Zeng G H, et al. Experimental research on high resolution terahertz radar imaging. High Power Laser Particle Beams, 2012, 24: 7-9 [蔡英武, 杨陈, 曾耿华, 等. 太赫兹极高分辨力雷达成像试验研究. 强激光与粒子束, 2012, 24: 7-9]. Google Scholar

[10] Feng Z H, Li Y, Liang L W, et al. Requirement analysis of linearity for FMCW source using open-loop correction. In: Proceedings of the 2nd International Conference on Microwave and Millimeter Wave Technology, Beijing, 2000. 679-682. Google Scholar

[11] Yi T Z, He Z H, Dong Z. Open-loop correction method for nonlinear error of frequency modulated continuous wave SAR. Acta Electron Sin, 2015, 43: 550-556 [易天柱, 何志华, 董臻. 调频连续波SAR非线性误差的开环矫正方法. 电子学报, 2015, 43: 550-556]. Google Scholar

[12] Peyton Z, Pecbles J. Design of a Highly Linear Closed-Loop FMCW Sweep Generator. Technical Report ADA108512. 1979. Google Scholar

[13] Sun P, Chen W D. Analysis of LFMCW delay phase-locked linearization loop. Syst Eng Electron, 2004, 26: 1348-352 [孙鹏, 陈卫东. LFMCW延迟锁相线性化环路分析. 系统工程与电子技术, 2004, 26: 1348-352]. Google Scholar

[14] Sun P, Chen W D. A nonlinear analysis of closed-loop linearizer employing delay-difference method. In: Proceedings of the 4th International Conference on Microwave and Millimeter Wave Technology, Beijing, 2004. 690-693. Google Scholar

[15] Meta A, Hoogeboom P, Ligthart L P. Signal processing for FMCW SAR. IEEE Trans GRS, 2007, 45: 3519-3532. Google Scholar

[16] Anghel A, Vasile G, Cacoveanu R, et al. Short-range wideband FMCW radar for millimetric displacement measurements. IEEE Trans Geosci Remote Sens, 2014, 52: 5633-5642 CrossRef Google Scholar

[17] Anghel A, Vasile G, Cacoveanu R, et al. Short-range FMCW X-band radar platform for millimetric displacements measurement. In: Proceedings of IEEE International Geoscience and Remote Sensing Symposium, Melbourne, 2013. 1111-1114. Google Scholar

[18] Anghel A, Vasile G, Cacoveanu R, et al. FMCW transceiver wideband sweep nonlinearity software correction. In: Proceedings of IEEE Radar Conference, Ottawa, 2013. 1-5. Google Scholar

[19] Barbarossa S, Scaglione A, Giannakis G B. Product high-order ambiguity function for multicomponent polynomial-phase signal modeling. IEEE Trans Signal Process, 1998, 46: 691-708 CrossRef Google Scholar

[20] Ding L F. Radar Principles. 5th ed. Beijing: Publishing House of Electronics Industry, 2014. 226 [丁鹭飞. 雷达原理. 第5版. 北京: 电子工业出版社, 2014. 226]. Google Scholar

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