A weighting solution based on the original Loffeld's bistatic formula (LBF) is addressed briefly in this paper to deal with the cases with noticeable difference between transmitter and receiver's velocities. T...
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ISBN:
(纸本)9781424428700
A weighting solution based on the original Loffeld's bistatic formula (LBF) is addressed briefly in this paper to deal with the cases with noticeable difference between transmitter and receiver's velocities. The published LBF-based approaches use range blocks to deal with the range variance. Alternatively, a new wavenumber domain algorithm is proposed by using the linearization of bistatic range, which follows the same routine of the monostatic omega-k algorithm. The approximation in this range linearization is examined with space-surface hybrid and airborne bistatic configurations. Due to large phase error for the airborne case, a second phase multiply have to be used in its focusing. This approach results in a good focusing performance over simulated data.
Bistatic SAR uses separate flying transmitter and receiver platforms. There are two principle configurations : spatial invariant case, in which velocity vectors are equal, and spatial variant case.. in which velocity ...
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ISBN:
(纸本)0780390504
Bistatic SAR uses separate flying transmitter and receiver platforms. There are two principle configurations : spatial invariant case, in which velocity vectors are equal, and spatial variant case.. in which velocity vectors are not equal. ONERA and DLR performed experimental flights oil the spatial invariant case in february 2003 [1]. The experiment was conducted using the X-band front ends that are compatible in terms of frequency (oil a 100 MHz-Wide band). Estimation and compensation of the phase drift between the transmitter and the receiver master oscillator was presented in [1]. Until flow, data have been processed with a back projection algorithm. This article investigates ail omega-k aloorithm - or Range Migration algorithm - for bistatic SAR systems in spatial invariant cases. First results of this algorithm oil real data are included.
Bistatic SAR uses separated transmitter in receiver flying on different platforms to achieve benefits like exploitation of additional information contained in the bistatic reflectivity of targets, reduced vulnerabilit...
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ISBN:
(纸本)0780390504
Bistatic SAR uses separated transmitter in receiver flying on different platforms to achieve benefits like exploitation of additional information contained in the bistatic reflectivity of targets, reduced vulnerability in military systems, forward looking SAR imaging Ill or increased RCS. Besides of technical problems, like the synchronization of the oscillators, the involved adjustment of transmit pulse versus receive gate timing, antenna pointing, flight coordination and motion compensation, the development of bistatic focusing algorithm is still in progress and not sufficiently solved. As a step to,I numerically efficient processor, an omega-k type algorithm is presented in the first part of this paper. The second part of this paper deals with it bistatic SAR experiment performed in October 2003, where two SAR systems of FGAN have been flown on two different airplanes. First bistatic SAR images we presented.
This paper utilizes the methodology of SAR2 algorithm, a two dimensional variant of the omega-k algorithm, to refocus out-of-focus images. Refocusing of images may be necessary in machine vision as a preprocessing ste...
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ISBN:
(纸本)9780819468451
This paper utilizes the methodology of SAR2 algorithm, a two dimensional variant of the omega-k algorithm, to refocus out-of-focus images. Refocusing of images may be necessary in machine vision as a preprocessing step before edge detection or image segmentation in the imaging and manipulation of 3D objects. The SAR2 algorithm generates a complex amplitude distribution and the corresponding point spread function in a manner similar to Fraunhofer diffraction distribution model and its point spread function as seen in Fourier optics. The matched filter utilized in the SAR2 algorithm has a focus-in-altitude interpretation and may be varied to increase or decrease the radius of out-of-focus blur associated with a particular point spread function of seatterers of various heights. This paper demonstrates focusing of a line object L={1 : x=y;-64 <= x <= 63;-64 <= y <= 63). Although a rectangular aperture is used in the refocusing process, other apertures may also be used such as circular or Gaussian.
High resolution sonars are required to detect and classify mines on the sea-bed. Synthetic aperture sonar increases the sonar cross range resolution by several orders of magnitudes while maintaining or increasing the ...
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ISBN:
(纸本)0819464600
High resolution sonars are required to detect and classify mines on the sea-bed. Synthetic aperture sonar increases the sonar cross range resolution by several orders of magnitudes while maintaining or increasing the area search rate. The resolution is however strongly dependent on the precision with which the motion errors of the platform can be estimated. The term micro-navigation is used to describe this very special requirement for sub-wavelength relative positioning of the platform. Therefore algorithms were designed to estimate those motion errors and to correct for them during the (w, k)-reconstruction phase. To validate the quality of the motion estimation algorithms a single transmitter/multiple receiver simulator was build, allowing to generate multiple point targets with or without surge and/or sway and/or yaw motion errors. The surge motion estimation is shown on real data, which were taken during a sea trial in November of 2003 with the low frequency (12 kHz) side scan sonar (LFSS) moving on a rail positioned on the sea-bed near Marciana Marina on the Elba Island, Italy.
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