scholarly journals An Improved Imaging Algorithm for High-Resolution Spotlight SAR with Continuous PRI Variation Based on Modified Sinc Interpolation

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 389 ◽  
Author(s):  
Shiyang Chen ◽  
Lijia Huang ◽  
Xiaolan Qiu ◽  
Mingyang Shang ◽  
Bing Han
Keyword(s):  
High Resolution ◽  
Pulse Repetition Frequency ◽  
Simulated Data ◽  
Pulse Repetition ◽  
Computationally Efficient ◽  
Imaging Algorithm ◽  
Sinc Interpolation ◽  
Kernel Length ◽  
Repetition Interval ◽  
Continuous Pulse

This paper focuses on an improved imaging algorithm for spotlight synthetic aperture radar (SAR) with continuous Pulse Repetition Interval (PRI) variation in extremely high-resolution. Conventional SAR systems are limited in that a wide swath cannot be achieved with a high azimuth resolution in the meantime. This limitation can be overcome by Pulse Repetition Frequency (PRF) variation in a SAR system. However, there are problems such as the ambiguities of point targets or extended targets caused by nonuniform sampling. A reconstructive method, Nonuniform Discrete Fourier Transform (NUDFT) has been presented in the current literature, but it is rather computationally expensive. In this paper, a modified sinc interpolation based on NUDFT is proposed, which is used to reconstruct the uniformly sampled echo in time domain. Since the interpolation kernel length is relatively short, it is more computationally efficient. Then, the two-step processing approach combined with the modified sinc interpolation is further presented, which has much better accuracy than that combined with the conventional sinc interpolation. Both the simulated data and the extracted GF-3 data experiment demonstrate the validity and accuracy of the proposed approach.

Continuous pulse repetition interval variation for highly squint high-resolution spotlight SAR imaging

2021 ◽  
Vol 12 (3) ◽  
pp. 209-218
Author(s):  
Hang Zou ◽  
Fengjun Zhao ◽  
Xiaoxue Jia ◽  
Wei Wang ◽  
Heng Zhang
Keyword(s):  
High Resolution ◽  
Pulse Repetition ◽  
Sar Imaging ◽  
Repetition Interval ◽  
Continuous Pulse

scholarly journals Slow Pulse Repetition Interval Variation for High-Resolution Wide-Swath SAR Imaging

2020 ◽  
pp. 1-22
Author(s):  
Felipe Queiroz de Almeida ◽  
Marwan Younis ◽  
Pau Prats-Iraola ◽  
Marc Rodriguez-Cassola ◽  
Gerhard Krieger ◽  
...  
Keyword(s):  
High Resolution ◽  
Pulse Repetition ◽  
Slow Pulse ◽  
Sar Imaging ◽  
Repetition Interval ◽  
Wide Swath

scholarly journals Implementation of Staggered Pulse Repetition Frequency RADAR Tracking with Xilinx FPGA

2019 ◽  
Vol 8 (4) ◽  
pp. 7035-7038
Keyword(s):  
Pulse Repetition Frequency ◽  
Shift Register ◽  
Repetition Frequency ◽  
Pulse Repetition ◽  
Pseudorandom Number ◽  
Pseudorandom Number Generator ◽  
Number Generator ◽  
Radar Tracking ◽  
Repetition Interval ◽  
Xilinx Fpga

This paper implements a Pulse Repetition Interval tracker against Staggered PRI Radar. Tracking of Staggered PRI is done using the IAR Embedded Workbench on STR710 microcontroller. Staggered Pulse Repetition Frequency is generated using Pseudorandom Number Generator using Linear Feed Back Shift Register in VHDL and implemented in Spartan-3E.

scholarly journals Design and Processing Method for Doppler-Tolerant Stepped-Frequency Waveform Using Staggered PRF

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6673
Author(s):  
Yan Zhang ◽  
Chunmao Yeh ◽  
Zhangfeng Li ◽  
Yaobin Lu ◽  
Xuebin Chen
Keyword(s):  
High Resolution ◽  
Design Method ◽  
Pulse Repetition Frequency ◽  
Waveform Design ◽  
Repetition Frequency ◽  
Pulse Repetition ◽  
Electromagnetic Data ◽  
Range Profile ◽  
Stepped Frequency ◽  
High Resolution Range Profile

Stepped-frequency waveform may be used to synthesize a wideband signal with several narrow-band pulses and achieve a high-resolution range profile without increasing the instantaneous bandwidth. Nevertheless, the conventional stepped-frequency waveform is Doppler sensitive, which greatly limits its application to moving targets. For this reason, this paper proposes a waveform design method using a staggered pulse repetition frequency to improve the Doppler tolerance effectively. First, a generalized echo model of the stepped-frequency waveform is constructed in order to analyze the Doppler sensitivity. Then, waveform design is carried out in the stepped-frequency waveform by using a staggered pulse repetition frequency so as to eliminate the high-order phase component that is caused by the target’s velocity. Further, the waveform design method is extended to the sparse stepped-frequency waveform, and we also propose corresponding methods for high-resolution range profile synthesis and motion compensation. Finally, experiments with electromagnetic data verify the high Doppler tolerance of the proposed waveform.

A High-resolution Imaging Algorithm for MIMO SAR Based on the Sub-band Synthesis in Frequency Domain

2011 ◽  
Vol 33 (5) ◽  
pp. 1082-1087 ◽  
Author(s):  
Yun-kai Deng ◽  
Qian Chen ◽  
Hai-ming Qi ◽  
Hui-fang Zheng ◽  
Ya-dong Liu
Keyword(s):  
High Resolution ◽  
Frequency Domain ◽  
High Resolution Imaging ◽  
Imaging Algorithm ◽  
Resolution Imaging

scholarly journals Effects of Non-thermal Ultrasound on a Fibroblast Monolayer Culture: Influence of Pulse Number and Pulse Repetition Frequency

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5040
Author(s):  
Silvia Ronda Peñacoba ◽  
Mar Fernández Gutiérrez ◽  
Julio San Román del Barrio ◽  
Francisco Montero de Espinosa
Keyword(s):  
Short Pulse ◽  
Pulse Repetition Frequency ◽  
Pulse Number ◽  
Repetition Frequency ◽  
Pulse Repetition ◽  
Treatment Protocols ◽  
Culture Plate ◽  
New Treatment ◽  
Long Pulse

Despite the use of therapeutic ultrasound in the treatment of soft tissue pathologies, there remains some controversy regarding its efficacy. In order to develop new treatment protocols, it is a common practice to carry out in vitro studies in cell cultures before conducting animal tests. The lack of reproducibility of the experimental results observed in the literature concerning in vitro experiments motivated us to establish a methodology for characterizing the acoustic field in culture plate wells. In this work, such acoustic fields are fully characterized in a real experimental configuration, with the transducer being placed in contact with the surface of a standard 12-well culture plate. To study the non-thermal effects of ultrasound on fibroblasts, two different treatment protocols are proposed: long pulse (200 cycles) signals, which give rise to a standing wave in the well with the presence of cavitation (ISPTP max = 19.25 W/cm2), and a short pulse (five cycles) of high acoustic pressure, which produces a number of echoes in the cavity (ISPTP = 33.1 W/cm2, with Pmax = 1.01 MPa). The influence of the acoustic intensity, the number of pulses, and the pulse repetition frequency was studied. We further analyzed the correlation of these acoustic parameters with cell viability, population, occupied surface, and cell morphology. Lytic effects when cavitation was present, as well as mechanotransduction reactions, were observed.

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