The radar systems have been so significant for both civil use and national defense, and adopting localized processor has become critical for a country, especially for the area related to the national defense. In this ...
详细信息
ISBN:
(纸本)9781849199940
The radar systems have been so significant for both civil use and national defense, and adopting localized processor has become critical for a country, especially for the area related to the national defense. In this paper, we utilize localized BWDSP100 as the main processor, and implement a high-speed and real-time signal processing system by using BWDSP100 + FPGA framework. We use FPGA to realize the interface conversions and extensions, which enhance the reading bandwidth of the DDR2 interface from 235MB/s to 562MB/s. Besides that, we also integrate highspeed serial buses, such as PCIe interface of 243MB/s and SRIO interface of 344MB/s, for communications in or between boards. The system has been used in several projects, and works well.
When synthetic aperture radar (SAR) works at the squint mode with a large grazing angle, the range walk varies obviously with the slant range. The traditional SPECAN algorithm corrects the range walk only based on the...
详细信息
ISBN:
(纸本)9781849199940
When synthetic aperture radar (SAR) works at the squint mode with a large grazing angle, the range walk varies obviously with the slant range. The traditional SPECAN algorithm corrects the range walk only based on the central slant range. Thus there are residual range walks at range edges of the swath, which finally leads to the defocus of the image. In order to solve this problem, a modified SPECAN algorithm based on the Chirp Scaling principle is proposed in this paper. First, the received data is multiplied by Chirp Scaling factor in the two-dimension time domain to eliminate the range variation of the range walk. Then the traditional SPECAN algorithm is applied to accomplish the two-dimension focus of the image. Simulation results confirm the validity of the proposed algorithm.
This paper presents a use of multi-core DSP TMS320C6678 for the squinted-looking synthetic aperture radars (SARs) real-time signal processing method. This paper first briefly introduces the squinted-looking SAR algori...
详细信息
ISBN:
(纸本)9781849199940
This paper presents a use of multi-core DSP TMS320C6678 for the squinted-looking synthetic aperture radars (SARs) real-time signal processing method. This paper first briefly introduces the squinted-looking SAR algorithm and analyzes the signal processing by use of spectral analysis (SPECAN). Then, according to the requirement of squinted-looking SAR real-time imaging system, the high performance TI multi-core DSP TMS320C6678 is used for realizing the imaging algorithm through the virtual single-node technology for data transmission and interaction and the parallel approach to data processing. Finally, the flight experiment is carried out and the results show that the virtual processing method meets the requirements of the real-time imaging based on the multi-core DSP hardware platform effectively.
Compared to the traditional SAR imaging algorithm, Back Projection(BP) algorithm is an accurate point-by-point imaging radar algorithm based on time-domain, with simple principle and without any approximation error in...
详细信息
ISBN:
(纸本)9781849199940
Compared to the traditional SAR imaging algorithm, Back Projection(BP) algorithm is an accurate point-by-point imaging radar algorithm based on time-domain, with simple principle and without any approximation error in the imaging process. However, because of intensive computation and low efficiency, it's a new challengetostorage to capacity, throughput and processing ability of DSPs, a single DSP is not enough to meet these demands. So a parallel implementation method of BP algorithm based on TMS320C6678 DSP is proposed in this *** put forward a large point FFT multi-core parallel processing method on 2/4/8 cores what is frequently used in BP algorithm, and a multi-core synchronization method based on distributed memory. Finally using the measured data, we verify the parallel method can greatly enhance the multi-core parallelism, and the real-time performance of BP algorithm has been significantly improved.
High-resolution SAR are of great value in remote sensing nowadays. To make good use of the characteristics of high-resolution SAR images to detect targets, we present here a region growing method. First, we calculate ...
详细信息
ISBN:
(纸本)9781849199940
High-resolution SAR are of great value in remote sensing nowadays. To make good use of the characteristics of high-resolution SAR images to detect targets, we present here a region growing method. First, we calculate a threshold according to the given PFA to pick up bright pixels as the seeds. Second, we define the criteria which is mainly based on the relationship between pixels in a high-resolution SAR image and then execute the growing process. Finally, we exclude false alarms according to some geometry features. The experiments and results show that it is a constructive and effective way using region growing algorithm to detect ships in high-resolution SAR images.
Considering the accuracy of traditional echo simulation methods, an improved echo simulation method of geosynchronous synthetic aperture radar (GEO SAR) is proposed, which has a higher accuracy. Aiming at the fidelity...
详细信息
ISBN:
(纸本)9781849199940
Considering the accuracy of traditional echo simulation methods, an improved echo simulation method of geosynchronous synthetic aperture radar (GEO SAR) is proposed, which has a higher accuracy. Aiming at the fidelity of echo simulation, this article develops a target scene model based on curved surface and an algorithm for judging whether the targets are illuminated by the beam. The echo simulation method is conducted with GEOSAR parameters, which indicates the correctness of scene model and beam judging algorithm. What's more, the effect of scene model and judging algorithm on imaging algorithm is analyzed. And the approach in this paper has a significant meaning for the investigation of space-borne SAR echo simulation and imaging algorithm.
In this paper, we focus on the widely-used radix-22 Decimation-In-Frequency (DIF) Fast Fourier Transform (FFT) algorithm. A variable-length, controllable-precision FFT processor is proposed. The processor can perform ...
详细信息
ISBN:
(纸本)9781849199940
In this paper, we focus on the widely-used radix-22 Decimation-In-Frequency (DIF) Fast Fourier Transform (FFT) algorithm. A variable-length, controllable-precision FFT processor is proposed. The processor can perform 16, 64, 256 and 1024 point FFT/IFFT and provide flexible wordlength scaling modes for different FFT stages. Thus, the processor is suitable for different precision and FFT length requirements in various applications. Aiming at high throughput performance, single-path delay feedback (SDF) pipeline architecture is adopted. The design is testified on Xilinx Virtex6 xc6vcx240t FPGA. Accordingly, we make a clear comparison between the proposed design and Xilinx FFT v7.1. Our design achieves better signal-to-quantizationnoise ratio (SQNR) property and shorter pipeline latency. Meanwhile, the occupied resource is approximately the same. Moreover, SQNR performance of different FFT length and wordlength scaling modes is analysed.
Interferometric synthetic aperture radar (InSAR) can realize the elevation extraction of the target. Through increasing the degree of freedom (DOF) during the topography calculation, multi-frequency InSAR technology c...
详细信息
ISBN:
(纸本)9781849199940
Interferometric synthetic aperture radar (InSAR) can realize the elevation extraction of the target. Through increasing the degree of freedom (DOF) during the topography calculation, multi-frequency InSAR technology can further achieve high-accuracy elevation reconstruction in steep terrain. Although the maximum likelihood estimation (MLE) method is widely used in the signal processing of multi-frequency InSAR, its performance can be influenced by phase noise. This paper proposes a creative algorithm which combines the maximum likelihood elevation estimation with the shortest sub-interval seeking operator (SSIS-MLE). It statistically averages the elevation estimation results of the MLE with class histogram, so that efficiently excludes the error estimation. Simulation results verify that this method not only maintains the high calculation efficiency of traditional MLE method, but also guarantees the high accuracy of elevation estimation.
In this paper, the effect of the satellite yawing, pitching and rotating to the antenna beam pointing is analyzed. At the same time, how the antenna beam pointing error affecting the imaging quality is interpreted. Th...
详细信息
ISBN:
(纸本)9781849199940
In this paper, the effect of the satellite yawing, pitching and rotating to the antenna beam pointing is analyzed. At the same time, how the antenna beam pointing error affecting the imaging quality is interpreted. The most significant effect is that the pointing error will lead to paired echo in the SAR image and the paired echo may submerge the weak target. So in this paper we will present a method based on minimum entropy to compensate the beam pointing error and eliminate the paired echo. Finally, we present some simulation to verify the validity of the compensated method.
Differentazimuth targets have different Doppler centroid and different time support domain in slide spotlight synthetic aperture radar. Thus, it is hard to weighting windowon the echo in slide spotlight mode. This pap...
详细信息
ISBN:
(纸本)9781849199940
Differentazimuth targets have different Doppler centroid and different time support domain in slide spotlight synthetic aperture radar. Thus, it is hard to weighting windowon the echo in slide spotlight mode. This paper proposed an azimuth weightingmethod of slide spotlight SAR based on subaperture chirp scaling algorithm. Firstly, the subaperture number of the algorithm is discussed based on the shift of Doppler centroid and the pulse repetition frequency(PRF). Secondly, the range cell migration and the remove of the azimuth phase of each subapertureare processed by chirp scaling algorithm independently. At last, the data of each subapertureis combined together, and the azimuth weighting window is applied after an azimuth de-ramp process of the combined data. The computer simulationsverify the validityof the proposed algorithm.
暂无评论