基于时频联合尺度变换的中轨SAR斜视成像方法

doi:10.3969/j.issn.1001-506X.2020.02.08

系统工程与电子技术 ›› 2020, Vol. 42 ›› Issue (2): 309-314.doi: 10.3969/j.issn.1001-506X.2020.02.08

基于时频联合尺度变换的中轨SAR斜视成像方法

陈权^1,²(), 孙光才^1,²(), 刘文康^1,²(), 邢孟道^1,²()

1. 西安电子科技大学雷达信号处理国家重点实验室, 陕西西安 710071
2. 西安电子科技大学信息感知技术协同创新中心, 陕西西安 710071

收稿日期:2019-05-14 出版日期:2020-02-01 发布日期:2020-01-23
作者简介:陈权 (1994-),男,博士研究生,主要研究方向为星载合成孔径雷达成像。E-mail:chenquan_cc@163.com|孙光才 (1984-),男,副教授,博士,主要研究方向为多通道波束指向SAR成像SAR动目标成像。E-mail:gcsun@xidian.edu.cn|刘文康 (1990-),男,博士研究生,主要研究方向为合成孔径雷达信号处理。wkliu@xidian.edu.cn|邢孟道 (1975-),男,教授,博士,主要研究方向为雷达成像和目标识别等。E-mail:xmd@xidian.edu.cn
基金资助:
国家重点研发计划(2017YFC1405600);国家自然科学基金创新群体基金号(61621005);中央高校基本业务费(JB180213)

Highly-squinted MEO SAR focusing based on joint time and doppler scaling

Quan CHEN^1,²(), Guangcai SUN^1,²(), Wenkang LIU^1,²(), Mengdao XING^1,²()

1. National Lab of Radar Signal Processing, Xidian University, Xi'an 710071, China
2. Collaborative Innovation Center of Information Sensing and Understand, Xidian University, Xi'an 710071, China

Received:2019-05-14 Online:2020-02-01 Published:2020-01-23
Supported by:
国家重点研发计划(2017YFC1405600);国家自然科学基金创新群体基金号(61621005);中央高校基本业务费(JB180213)

摘要/Abstract

摘要：

在中轨合成孔径雷达(synthetic aperture radar, SAR)成像中,大斜视角以及长合成孔径时间会导致信号产生严重的距离走动和二维空变。首先，针对信号的距离走动问题,采用了变脉冲重复频率(pulse repetition frequency, PRF)技术对回波进行录取,消除大距离走动带来的回波接收问题。然后，针对传统的波数域算法不能实现大斜视中轨SAR信号的聚焦问题,提出了一种结合改进的Stolt插值的时频联合尺度变换的成像方法,利用方位时间尺度变换来解决信号方位调频率的2次空变,再使用改进的Stolt插值完成距离徙动校正。最后,利用多普勒尺度变换来处理剩余的高次空变。通过仿真结果可以证明所提算法的有效性。

关键词: 中轨SAR, 二维空变, 变PRF, 时频联合尺度变换

Abstract:

The squinted observation geometry along with long integration time significantly increases the space variance of the medium-Earth-orbit SAR signal. Firstly, in order to solve the range walk of the signal, a variable pulse repetition frequency (PRF) technology was used to receive the echos. Variable pulse repetition frequency is recommended to handle the severe range walk. The existing wavenumber algorithms cannot handle the nonlinear and range-azimuth-coupled space variance over a large scene. We propose a modified Stolt mapping method along with a modified joint time and Doppler scaling for imaging. An azimuth time scale transformation is used to deal with the quadratic space variance of the azimuth frequency modulation rate. A modified Stolt mapping is used to correct range cell migration. To address the range-azimuth-coupled space variance, the Doppler linearization is done in the range-Doppler domain using range-dependent Doppler scale transformation. Simulation results are shown to verify the effectiveness of the developed focusing approaches.

Key words: medium-Earth-orbit (MEO) SAR, 2-D space variance, variable pulse repetition frequency (PRF), joint time-frequency scale transformation

中图分类号:

TN957

陈权, 孙光才, 刘文康, 邢孟道. 基于时频联合尺度变换的中轨SAR斜视成像方法[J]. 系统工程与电子技术, 2020, 42(2): 309-314.

Quan CHEN, Guangcai SUN, Wenkang LIU, Mengdao XING. Highly-squinted MEO SAR focusing based on joint time and doppler scaling[J]. Systems Engineering and Electronics, 2020, 42(2): 309-314.

图/表 7

图1

图2

图3

图4

表1

图5

表2

参考文献 19

1	MADSEN S N, CHEN C, EDELSTEIN W.Radar options for global earthquake monitoring[C]//Proc.of the International Geoscience and Remote Sensing Symposium, 2002, 3(3): 1483-1485.
2	TOMIYASU K . Conceptual performance of a satellite borne, wide swath synthetic aperture radar[J]. IEEE Trans.on Geoscience and Remote Sensing, 1981, 19 (2): 108- 116.
3	JALAL M, PACO L D, GERHARD K. Potentials and limitations of MEO SAR[C]//Proc.of the European Conference on Synthetic Aperture Radar, 2016: 1-5.
4	HUANG L J , QIU X L , HU D H , et al. Focusing of medium- earth-orbit SAR with advanced nonlinear chirp scaling algorithm[J]. IEEE Trans.on Geoscience and Remote Sensing, 2011, 49 (1): 500- 508. doi: 10.1109/TGRS.2010.2053211
5	BAO M , XING M D , LI Y C , et al. Two-dimensional spectrum for MEO SAR processing using a modified advanced hyperbolic range equation[J]. Electronics Letters, 2011, 47 (18): 1043- 1045. doi: 10.1049/el.2011.1322
6	SUN G C , XING M D , WANG Y J , et al. A 2-D space-variant chirp scaling algorithm based on the RCM equalization and sub-band synthesis to process geosynchronous SAR data[J]. IEEE Trans.on Geoscience and Remote Sensing, 2014, 52 (8): 4868- 4880. doi: 10.1109/TGRS.2013.2285721
7	LIU W K , SUN G C , XIA X G , et al. A modified CSA based on joint time-Doppler resampling for MEO SAR stripmap mode[J]. IEEE Trans.on Geoscience and Remote Sensing, 2018, 56 (6): 3573- 3586. doi: 10.1109/TGRS.2018.2802545
8	ZENG T , LI Y H , DING Z G , et al. Subaperture approach based on azimuth-dependent range cell migration correction and azimuth focusing parameter equalization for maneuvering high-squint-mode SAR[J]. IEEE Trans.on Geoscience and Remote Sensing, 2015, 53 (12): 6718- 6734. doi: 10.1109/TGRS.2015.2447393
9	HUANG L J , QIU X L , HU D H , et al. Medium-earth-orbit SAR focusing using range doppler algorithm with integrated two-step azimuth perturbation[J]. IEEE Geoscience and Remote Sensing Letters, 2015, 12 (3): 626- 630. doi: 10.1109/LGRS.2014.2353674
10	LI Z Y , XING M D , LIANG Y , et al. A frequency-domain imaging algorithm for highly squinted SAR mounted on maneuvering platforms with nonlinear trajectory[J]. IEEE Trans.on Geoscience and Remote Sensing, 2016, 54 (7): 4023- 4038. doi: 10.1109/TGRS.2016.2535391
11	CHEN J , KUANG H , YANG W , et al. A novel imaging algorithm for focusing high-resolution spaceborne SAR data in squinted sliding- spotlight mode[J]. IEEE Geoscience and Remote Sensing Letters, 2016, 13 (10): 1577- 1581. doi: 10.1109/LGRS.2016.2598066
12	LI D , LIN H , LIU H Q , et al. Focus improvement for high-resolution highly squinted SAR imaging based on 2-D spatial-variant linear and quadratic RCMs correction and azimuth-dependent Doppler equalization[J]. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2017, 10 (1): 168- 183. doi: 10.1109/JSTARS.2016.2569561
13	LI D X , WU M Q , SUN Z Y , et al. Modeling and processing of two-dimensional spatial-variant geosynchronous SAR data[J]. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2015, 8 (8): 3999- 4009. doi: 10.1109/JSTARS.2015.2418814
14	TANG S Y , LIN C H , ZHOU Y , et al. Processing of long integration time spaceborne SAR data with curved orbit[J]. IEEE Trans.on Geoscience and Remote Sensing, 2018, 52 (2): 888- 904.
15	WANG Y , LI J W , YANG J . Wide nonlinear chirp scaling algorithm for spaceborne stripmap range sweep SAR imaging[J]. IEEE Trans.on Geoscience and Remote Sensing, 2017, 55 (12): 6922- 6936. doi: 10.1109/TGRS.2017.2737031
16	王沛, 徐伟, 李宁, 等. 星载大斜视聚束SAR变PRI成像技术研究[J]. 电子与信息学报, 2018, 40 (10): 2470- 2477.
	WANG P , XU W , LI N , et al. Investigation on PRI variation for high squint spaceborn spotlight SAR[J]. Journal of Electronics & Information Technology, 2018, 40 (10): 2470- 2477.
17	PELIPE Q A , YOUNIS M , KRIEGER G . Multichannel staggered SAR azimuth processing[J]. IEEE Trans.on Geoscience and Remote Sensing, 2018, 56 (5): 2772- 2788. doi: 10.1109/TGRS.2017.2783444
18	VILLANO M, PINHEIRO M, KRIEGER G, et al. Gapless imaging with the NASA- ISRO SAR(NISAR) mission: challenges and opportunities of staggered SAR[C]//Proc.of the European Conference on Synthetic Aperture Radar, 2018: 1-6.
19	CHEN J L , SUN G C , YANG J , et al. A TSVD-NCS algorithm in range-Doppler domain for geosynchronous synthetic aperture radar[J]. IEEE Geoscience and Remote Sensing Letters, 2016, 13 (11): 1631- 1635. doi: 10.1109/LGRS.2016.2599224

类型	名称	值
轨道参数	轨道高度/km	7 000
	偏心率	0
	倾角/(°)	90
	近地点幅角/(°)	0
雷达参数	载频/GHz	5.4
	带宽/MHz	200
	PRF/Hz	4 000
	斜视角/(°)	40
	合成孔径时间/s	50
	地面距离/多普勒分辨率/m	2/2
场景参数	地斜角/(°)	60
	方位场景宽度/km	40
	距离场景宽度/km	40

点目标		PSLR/dB		ISLR/dB
点目标		距离向	方位向	距离向	方位向
本文方法	A点	-13.29	-13.22	-10.04	-10.02
	B点	-13.33	-13.28	-10.05	-10.02
	C点	-13.33	-13.24	-10.05	-10.01
文献[6]方法	A点	-13.21	-11.35	-9.71	-8.41
	B点	-13.24	-13.24	-9.76	-10.08
	C点	-13.24	-11.34	-9.74	-8.30

基于时频联合尺度变换的中轨SAR斜视成像方法

Highly-squinted MEO SAR focusing based on joint time and doppler scaling

RichHTML

PDF (PC)

可视化

摘要/Abstract

引用本文

使用本文

图/表 7

参考文献 19

相关文章 1

编辑推荐

Metrics

本文评价