Inverse synthetic aperture ladar imaging with stepped‐frequency continuous waveform

2017 ◽  
Vol 53 (21) ◽  
pp. 1424-1426
Author(s):  
Guangzuo Li ◽  
Ning Wang ◽  
Di Mo ◽  
Ran Wang ◽  
Zenghui Zhang ◽  
...  
Keyword(s):  
Synthetic Aperture ◽  
Stepped Frequency

scholarly journals An Efficient Signal Reconstruction Algorithm for Stepped Frequency MIMO-SAR in the Spotlight and Sliding Spotlight Modes

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Jiajia Zhang ◽  
Guangcai Sun ◽  
Mengdao Xing ◽  
Zheng Bao ◽  
Fang Zhou
Keyword(s):  
Efficient Algorithm ◽  
Low Cost ◽  
Signal Reconstruction ◽  
Multiple Input Multiple Output ◽  
Reconstruction Algorithm ◽  
Synthetic Aperture ◽  
Two Dimensional ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Stepped Frequency

Multiple-input multiple-output (MIMO) synthetic aperture radar (SAR) using stepped frequency (SF) waveforms enables a high two-dimensional (2D) resolution with wider imaging swath at relatively low cost. However, only the stripmap mode has been discussed for SF MIMO-SAR. This paper presents an efficient algorithm to reconstruct the signal of SF MIMO-SAR in the spotlight and sliding spotlight modes, which includes Doppler ambiguity resolving algorithm based on subaperture division and an improved frequency-domain bandwidth synthesis (FBS) method. Both simulated and constructed data are used to validate the effectiveness of the proposed algorithm.

scholarly journals Correction of Channel Imbalance for MIMO SAR Using Stepped-Frequency Chirps

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Xiulian Luo ◽  
Yunkai Deng ◽  
Robert Wang ◽  
Lei Guo ◽  
Mingjiang Wang
Keyword(s):  
Calibration Method ◽  
Synthetic Aperture ◽  
Chirp Pulse ◽  
Frequency Chirp ◽  
Channel Characteristics ◽  
Strong Point ◽  
Chirp Signals ◽  
Stepped Frequency ◽  
Peak Value ◽  
Wide Swath

To simultaneously achieve two-dimensional high resolution and wide swath in synthetic aperture radar (SAR), azimuth MIMO structure combined with stepped-frequency chirp signals was developed via splitting the antenna intoNsubapertures. During transmitting each subaperture transmits a chirp pulse at a different carrier frequency, while during receiving every subaperture receives theNscattered pulses at the same time. Separating theNscattered pulses received by each subaperture and downlinking them to the ground yieldN2different signal paths. Due to the dedicated network in the SAR system, the channel imbalance is inevitable. To correct the channel imbalance, this paper presents an external calibration method, where the channel characteristics are estimated from the peak value of a strong point target for each channel. Simulation and real raw data experiments are performed to validate the proposed method.

A Fully Automatic Autofocusing Algorithm for Post-processing ISAR Imaging based on Image Entropy Minimization

1970 ◽  
Vol 110 (4) ◽  
pp. 125-130
Author(s):  
E. D. Kallitsis ◽  
A. V. Karakasiliotis ◽  
G. E. Boultadakis ◽  
P. V. Frangos
Keyword(s):  
Computational Cost ◽  
Angular Acceleration ◽  
Synthetic Aperture ◽  
Post Processing ◽  
Acceptable Range ◽  
Image Entropy ◽  
Isar Imaging ◽  
Fully Automatic ◽  
Simulation Results ◽  
Stepped Frequency

Autofocus is a technique for improving inverse synthetic aperture radar (ISAR) imaging. In this paper, a novel autofocusing method is developed for high-resolution stepped-frequency ISAR. Non-uniform rotational motion is compensated through the proposed post-processing methodology. In this way, the computational cost of polar reformatting process can be circumvented. The proposed CPI-split autofocusing process results in well-focused ISAR images for high angular acceleration periods. Finally, ISAR image entropy dependencies are thoroughly examined through various simulation results, leading to an acceptable range of entropy values for the autofocusing process. Ill. 7, bibl. 9, tabl. 3 (in English; abstracts in English and Lithuanian).http://dx.doi.org/10.5755/j01.eee.110.4.305

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