Abstract
Waveform diversity (WD) represents a dynamic and transformative technology widely used in radar systems to enhance sensitivity and discrimination capabilities. Recently, WD techniques have been extensively explored for their potential ambiguity suppression within synthetic aperture radar (SAR) systems. Among these, the alternate transmitting mode combined with orthogonal waveforms emerges as a particularly promising solution. This study focuses on optimizing the power spectrum density (PSD) of signals to design and generate an orthogonal waveform pair that achieves both a low cross-correlation-to-autocorrelation ratio (CAR) and satisfactory imaging performance. Initially, we construct a fractional programming model with convex constraints to minimize the CAR. To address this challenge, we introduce an iterative optimization procedure for the PSD variable, which sequentially reduces the CAR. Each optimization step can be efficiently solved using a quadratically constrained quadratic program, ensuring that the resulting computational complexity remains low. Building on the optimized PSD, we established a parametric piecewise linear model to generate an orthogonal waveform pair. This model not only maintains a low CAR but achieves satisfactory imaging performance in real-time applications. Consequently, this orthogonal waveform pair effectively suppresses range ambiguity in SAR systems. Finally, we demonstrated the practicability and effectiveness of the proposed orthogonal waveforms through detailed simulation experiments, specifically targeting ambiguity suppression in conventional quad-polarization SAR systems.
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References
Cumming I G, Wong F H. Digital processing of synthetic aperture Radar data. Artech House, 2005, 1: 108–110
Deng Y-K, Zhao F-J, Wang Y. Brief analysis on the development and application of spaceborne SAR. J Radars, 2012, 1: 1–10
Raney R K, Freeman A, Jordan R L. Improved range ambiguity performance in quad-pol SAR. IEEE Trans Geosci Remote Sens, 2011, 50: 349–356
Villano M, Krieger G, Moreira A. New insights into ambiguities in quad-pol SAR. IEEE Trans Geosci Remote Sens, 2017, 55: 3287–3308
Zhang Y, Wang W, Deng Y, et al. Ambiguity suppression of cross-pol signals by DPCA with DBF reflector for hybrid/±π/4 quad-pol SAR. IEEE Trans Geosci Remote Sens, 2022, 60: 1–13
Krieger G, Gebert N, Moreira A. Multidimensional waveform encoding: a new digital beamforming technique for synthetic aperture radar remote sensing. IEEE Trans Geosci Remote Sens, 2008, 46: 31–46
Zhao Q, Zhang Y, Wang W, et al. On the frequency dispersion in DBF SAR and digital scalloped beamforming. IEEE Trans Geosci Remote Sens, 2020, 58: 3619–3632
Younis M, de Almeida F Q, Villano M, et al. Digital beamforming for spaceborne reflector-based synthetic aperture radar, part 1: basic imaging modes. IEEE Geosci Remote Sens Mag, 2021, 9: 8–25
Gebert N, Krieger G, Moreira A. Digital beamforming on receive: techniques and optimization strategies for high-resolution wide-swath SAR imaging. IEEE Trans Aerosp Electron Syst, 2009, 45: 564–592
Zhang Y, Wang W, Deng Y, et al. Signal reconstruction algorithm for azimuth multichannel SAR system based on a multiobjective optimization model. IEEE Trans Geosci Remote Sens, 2020, 58: 3881–3893
Dall J, Kusk A. Azimuth phase coding for range ambiguity suppression in SAR. In: Proceedings of IEEE International Geoscience and Remote Sensing Symposium, 2004. 3: 1734–1737
Jin G, Wang Y, Zhu D, et al. A reconfigurable MIMO-SAR transmission scheme based on inter-pulse and intra-pulse joint phase modulation. IEEE Trans Signal Process, 2022, 70: 4265–4276
Bordoni F, Younis M, Krieger G. Ambiguity suppression by azimuth phase coding in multichannel SAR systems. IEEE Trans Geosci Remote Sens, 2011, 50: 617–629
Zhang Y, Wang W, Deng Y, et al. Quadratically constrained ambiguity suppression algorithm for APC/multichannel SAR systems with nonuniform spatial sampling. IEEE Trans Geosci Remote Sens, 2020, 59: 1319–1330
Blunt S D, Mokole E L. Overview of radar waveform diversity. IEEE Aerosp Electron Syst Mag, 2016, 31: 2–42
Wicks M, Mokole E, Blunt S, et al. Principles of Waveform Diversity and Design. SciTech, 2010. https://digital-library.theiet.org/content/books/ra/sbra023e
Pillai U, Li K Y, Selesnick I, et al. Waveform Diversity: Theory and Applications. New York: McGraw-Hill, 2011
Gini F, Maio A D, Patton L. Waveform Design and Diversity for Advanced Radar Systems. London: Institution of Engineering and Technology, 2012
Harger R O. Synthetic Aperture Radar Systems: Theory and Design. 1971. https://www.semanticscholar.org/paper/Synthetic-aperture-radar-systems-%3A-theory-and-Harger/daf5c29125b8ddba79e457561a34cf83e63e5fe4
Mittermayer J, Martinez J M. Analysis of range ambiguity suppression in SAR by up and down chirp modulation for point and distributed targets. In: Proceedings of IEEE International Geoscience and Remote Sensing Symposium, 2003. 6: 4077–4079
Knapskog A O. Range ambiguity suppression in spaceborne SAR by up-and down-chirp modulation in combination with pseudo-random biphase coding. In: Proceedings of the 12th European Conference on Synthetic Aperture Radar, 2018. 1–4
Wang W Q. Mitigating range ambiguities in high-PRF SAR with OFDM waveform diversity. IEEE Geosci Remote Sens Lett, 2013, 10: 101–105
Riche V, Meric S, Baudais J-Y, et al. Optimization of OFDM SAR signals for range ambiguity suppression. In: Proceedings of the 9th European Radar Conference, 2012. 278–281
Riche V, Meric S, Baudais J Y, et al. Investigations on OFDM signal for range ambiguity suppression in SAR configuration. IEEE Trans Geosci Remote Sens, 2013, 52: 4194–4197
Xu Z, Wang R, Ye K, et al. Simultaneous range ambiguity mitigation and sidelobe reduction using orthogonal non-linear frequency modulated (ONLFM) signals for satellite SAR Imaging. Remote Sens Lett, 2018, 9: 829–838
Krieger G. MIMO-SAR: opportunities and pitfalls. IEEE Trans Geosci Remote Sens, 2014, 52: 2628–2645
Jin G, Deng Y, Wang R, et al. Mitigating range ambiguities with advanced nonlinear frequency modulation waveform. IEEE Geosci Remote Sens Lett, 2019, 16: 1230–1234
Jin G, Zhu D, Yan H, et al. New insights into SAR alternate transmitting mode based on waveform diversity. IEEE Trans Geosci Remote Sens, 2022, 60: 1–9
Sampson J R. Adaptation in natural and artificial systems (John H. Holland). SIAM Rev, 1976, 18: 529–530
Jin G, Deng Y, Wang R, et al. An advanced nonlinear frequency modulation waveform for radar imaging with low sidelobe. IEEE Trans Geosci Remote Sens, 2019, 57: 6155–6168
Ugray Z, Lasdon L, Plummer J, et al. Scatter search and local NLP solvers: a multistart framework for global optimization. INFORMS J Computing, 2007, 19: 328–340
Jin G, Aubry A, de Maio A, et al. Quasi-orthogonal waveforms for ambiguity suppression in spaceborne quad-pol SAR. IEEE Trans Geosci Remote Sens, 2022, 60: 1–17
Jin G, Wang W, Deng Y, et al. A novel range-azimuth joint modulation scheme for range ambiguity suppression. IEEE Trans Geosci Remote Sens, 2022, 60: 1–10
Dinkelbach W. On nonlinear fractional programming. Manage Sci, 1967, 13: 492–498
Boyd S, Boyd S P, Vandenberghe L. Convex Optimization. Cambridge: Cambridge University Press, 2004
Levanon N, Mozeson E. Radar Signals. Hoboken: John Wiley & Sons, 2004
Doerry A W. Generating Nonlinear FM Chirp Waveforms for Radar. Technical Report. Sandia National Laboratories, 2006
Zhang Y, Wang W, Wang R, et al. A novel NLFM waveform with low sidelobes based on modified Chebyshev window. IEEE Geosci Remote Sens Lett, 2019, 17: 814–818
Zhang Y, Deng Y, Zhang Z, et al. Analytic NLFM waveform design with harmonic decomposition for synthetic aperture radar. IEEE Geosci Remote Sens Lett, 2022, 19: 1–5
Jin G, Liu K, Deng Y, et al. Nonlinear frequency modulation signal generator in LT-1. IEEE Geosci Remote Sens Lett, 2019, 16: 1570–1574
Zhang Y, Deng Y, Zhang Z, et al. Parametric NLFM waveform for spaceborne synthetic aperture radar. IEEE Trans Geosci Remote Sens, 2022, 60: 1–9
Saeedi J, Faez K. Synthetic aperture radar imaging using nonlinear frequency modulation signal. IEEE Trans Aerosp Electron Syst, 2016, 52: 99–110
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This work was supported by National Key Research and Development Program of China (Grant No. 2023YFB3904901).
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Deng, Y., Zhang, Y., Zhang, Z. et al. Orthogonal waveform design with fractional programming on the ambiguity suppression of SAR systems. Sci. China Inf. Sci. 67, 192305 (2024). https://doi.org/10.1007/s11432-023-4076-7
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DOI: https://doi.org/10.1007/s11432-023-4076-7