Quantitative Analysis of Range resolution model of point scatterers in LFM chirp pulse radar
LFM chirp 펄스 레이더에서 거리분해능 모델에 대한 정량적 분석
- 주제(키워드) Terms—Chirp pulse , LFM (Linear Frequency Modulation) , Radar , Range resolution , SAR (Synthetic Aperture Radar) , Point Cloud model , clutter
- 주제(DDC) 355
- 발행기관 아주대학교 일반대학원
- 지도교수 Sang Chul Park
- 발행년도 2024
- 학위수여년월 2024. 2
- 학위명 박사
- 학과 및 전공 일반대학원 국방디지털융합학과
- 실제URI http://www.dcollection.net/handler/ajou/000000033267
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
The conventional range resolution is defined as 1/bandwidth (BW) and a functional range resolution is suggested as 2/BW for point scatterers. But, in actual radar situations, positions of peaks do not represent true locations of the scatterers. In addition, the amount of deviation between peaks and true locations is not proportionally decreased as the distance between the two increases. In this thesis, to explain and predict this situation in detail, a complex form of expression was derived in terms of the starting frequency for a linear frequency modulation (LFM) chirp pulse radar. A quantitative analysis approach to the range resolution was defined and applied to some of previous studies and the range profiles of magnitude envelope were analyzed and experimented for two point targets for cases with different starting frequencies of sweep frequencies within the same bandwidth. Finally a ‘map’ type of contour plot for the ‘quantitative’ range resolution was generated to anticipate and analyze resolution characteristics. It is analyzed that LFM continuous wave (CW) waveform show the very similar pattern as LFM pulse waveform. As a result of the new complex range resolution model, analyses were matched well with practical measurements experiments about the range resolution value for two point targets. Then, this new range resolution characteristics were applied to several two dimensional (range and azimuth) SAR images with 5-by-5 point scatterers and a few thousand point cloud scatterers beyond the two point targets. Most of the modeling of targets in image radar (SAR) was conducted by dividing them into ray tracing and statistical distribution model methods, In this thesis, a point cloud target model was created by representing artificial targets and Earth surface clusters as scattering points in a three-dimensional lattice space, as a result of creating an image radar (SAR) image and comparing it with the images of the actual vehicle-mounted SAR system, it was confirmed that it was useful. Index Terms—Chirp pulse, LFM (Linear Frequency Modulation), Radar, Range resolution, SAR (Synthetic Aperture Radar), Point Cloud model, clutter
more목차
I. Introduction . 1
I-1. Background . 1
I-2. Research Scope 5
II. Conventional range resolution analyses and quantitative analysis approach 9
II-1. Optical resolution 9
II-2. Conventional range resolution studies 11
II-2-1. Definition of the range resolution in radar engineering . 11
II-2-2. Rihaczek's studies by Gaussian model [2, 8] . 12
II-2-3. Wehner's studies by Sinc model [1] 15
II-2-4. Carlson's studies by Gaussian model [7] 16
II-2-5. Maio's studies by linear stepped frequency model [21] 18
II-2-6. Chang's studies by Sinc model with Electro-Magnetic (EM) field [25] 20
II-3. Quantitative analysis approach . 22
III. Quantitative range resolution analysis for Gaussian and Sinc waveform model 27
III-1. Review of Gaussian model and further analysis. 27
III-2. Review of Sinc model and further analysis 31
IV. Quantitative Range resolution analysis for LFM chirp waveform model 36
IV-1. LFM chirp waveform 36
IV-2. Analysis of exact LFM-pulse model 37
IV-3. Analysis of LFM-CW model 47
V. experiment and applications of LFM-pulse characteristics . 53
V-1. Experiment for two point scatterers by the LFM-pulse radar system 53
V-1-1. Estimation by mathematical simulation 53
V-1-2. Experiment by a LFM-pulse radar system 55
V-2. Extend to 5-by-5 point scatterers and apply to ship classification . 58
V-2-1. 5-by-5 point scatterers simulation 58
V-2-2. Application to a ship identification . 65
V-3. Extend to a large number of point cloud scatterers (a bridge) 69
V-3-1. Bridge detection and identification [32] 69
V-3-2. 3-D modeling of a bridge by point cloud scatterers [32] 69
V-3-3. SAR image processing of the 3-D point cloud bridge model . 71
VI. Conclusion 74
A1. Mathematica source code for Quantitative Calculation 75
A2. Exact LFM-pulse Model Equation Derivation 81
A3. MatLab source code for 5-by-5 points SAR 83
A4. 3-D Scatterers Point Cloud Target Model for SAR 87
References . 98
Abstract (Korean) 106
