摘要 :
This paper proposes an alternative form of the Keystone Transform (KT), which is known for mitigating range walk in radar returns. While traditionally applied as an interpolation to the cross ambiguity function (CAF), the present ...
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This paper proposes an alternative form of the Keystone Transform (KT), which is known for mitigating range walk in radar returns. While traditionally applied as an interpolation to the cross ambiguity function (CAF), the present work shows that the KT can be implemented prior to, and agnostic of, the cross correlation operation. The new time-domain KT algorithm is derived as a time-variant filter and demonstrated against simulated data. The computational cost, and architectural flexibility offered by the filter, are each examined.
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摘要 :
Conventional algorithms in ISAR imaging need to estimate the range migration of the target accurately to perform range alignment, which may be impossible in the case of multiple targets imaging. Keystone transform could correct th...
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Conventional algorithms in ISAR imaging need to estimate the range migration of the target accurately to perform range alignment, which may be impossible in the case of multiple targets imaging. Keystone transform could correct the range migrations of different targets without knowing their velocities. But keystone transform is limited by the Doppler central frequency and Doppler frequency band width. Researchers have tried to solve this limit so that all targets can be corrected together. But in this paper, the author makes use of this limit to separate the targets, whose velocities are far from each other. For these targets, only some of them are corrected and others will be filtered in the time-frequency domain by STFT. After separating the targets into individual ones, conventional method for phase compensation is performed and clearly image is obtained.
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摘要 :
Keystone transforms could correct range migration without the information about target velocity. In this paper, the principles and realizations of keystone transforms are analyzed. And keystone transforms using several interpolati...
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Keystone transforms could correct range migration without the information about target velocity. In this paper, the principles and realizations of keystone transforms are analyzed. And keystone transforms using several interpolation methods are evaluated. It is shown that using Sine, frequency sampling, Lagrange interpolation are superior to piecewise linear and 3-spline interpolation.
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摘要 :
Keystone transforms could correct range migration without the information about target velocity. In this paper, the principles and realizations of keystone transforms are analyzed. And keystone transforms using several interpolati...
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Keystone transforms could correct range migration without the information about target velocity. In this paper, the principles and realizations of keystone transforms are analyzed. And keystone transforms using several interpolation methods are evaluated. It is shown that using Sine, frequency sampling, Lagrange interpolation are superior to piecewise linear and 3-spline interpolation.
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摘要 :
The traditional time difference of arrival (TDOA) and frequency difference of arrival (FDOA) estimation method suffers from the huge computational complexity and the estimate stepwise caused by the discrete parameter space. Moreov...
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The traditional time difference of arrival (TDOA) and frequency difference of arrival (FDOA) estimation method suffers from the huge computational complexity and the estimate stepwise caused by the discrete parameter space. Moreover, the estimation performance deteriorates severely when the target moves rapidly. Therefore, a high accuracy method for joint TDOA and FDOA estimation based on the keystone transform and chirp-z transform is proposed. Firstly, the received signal data is divided into two-dimensional array of Fast Time (FT) and Slow Time (ST). And then the keystone transform is used to compensate the time delay migration due to the movement of target. Based on the compensated data, the coarse estimation of two parameters can be obtained by the utilization of the two-dimensional fast Fourier transform. In the following, the two-dimensional chirp-z transform is applied to reduce the search step of the region around the coarse estimation, so that the fine estimation of two parameters can be obtained. Finally, the quadratic function fitting is used to get the accurate estimation. Numerical simulations demonstrate the superiority of this method.
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摘要 :
The signal accumulation algorithm is one of the signal processing algorithms which is commonly used in the radar signal processing. However, with the growth of accumulation time, moving target will appear the problem of range migr...
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The signal accumulation algorithm is one of the signal processing algorithms which is commonly used in the radar signal processing. However, with the growth of accumulation time, moving target will appear the problem of range migration and Doppler migration. As a result, signal energy can't accumulate effectively, and the ability of radar to detect targets may be affected, so, motion compensation before integration is necessary. In this paper, a motion compensation method based on Keystone transform and Wigner-Hough transform is presented, which can correct the migration. Then simulation is carried out and the results verify its efficiency.
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摘要 :
The signal accumulation algorithm is one of the signal processing algorithms which is commonly used in the radar signal processing. However, with the growth of accumulation time, moving target will appear the problem of range migr...
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The signal accumulation algorithm is one of the signal processing algorithms which is commonly used in the radar signal processing. However, with the growth of accumulation time, moving target will appear the problem of range migration and Doppler migration. As a result, signal energy can't accumulate effectively, and the ability of radar to detect targets may be affected, so, motion compensation before integration is necessary. In this paper, a motion compensation method based on Keystone transform and Wigner-Hough transform is presented, which can correct the migration. Then simulation is carried out and the results verify its efficiency.
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摘要 :
For wideband radars, the Doppler ambiguity factor in keystone transform may be inconstant. Thus, the coherent integration gain is reduced. In this paper, a wideband keystone algorithm based upon the priori velocity compensation is proposed.
摘要 :
For wideband radars, the Doppler ambiguity factor in keystone transform may be inconstant. Thus, the coherent integration gain is reduced. In this paper, a wideband keystone algorithm based upon the priori velocity compensation is proposed.
摘要 :
For long-term energy integration detection, we must conduct echo envelope compensation to correct all targets echo to the same range bin, through MTD or joint time-frequency transform complete energy accumulation. Keystone transfo...
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For long-term energy integration detection, we must conduct echo envelope compensation to correct all targets echo to the same range bin, through MTD or joint time-frequency transform complete energy accumulation. Keystone transform is an effective method for range migration compensation, but this algorithm is large amount of calculation against real-time processing. We present a method for range migration compensation based on analysis of linear regression, it makes use of the curve fitting for the processing of the migration compensation. We compare the two methods of computational efficiency, linear regression algorithm has better real-time process performance, and the effectiveness is conformed by the simulation results.
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