摘要:
The change detection device (1) of the present invention inputs at least two SAR image sets (501) each holding at least information indicative of a reflection intensity and a phase so as to be associated with each of pixels corresponding to a resolution cell within a field of vision for image capturing including a specific region. The information is generated from observation data formed of four basic polarization pairs, i.e. HH, HV, VH and VV polarization pairs observed by a synthetic aperture radar at generally the same time. The change detection device (1) determines a polarization pair (502) whose reflection intensity is not less than a predetermined value or the highest with respect to each of target pixels by using at least one SAR image set among input SAR image sets, and measures displacement (503) at a spot corresponding to the target pixel based on a determined polarization pair and an input SAR image set.
摘要:
Some embodiments are directed to a radar imaging system that includes a radar transmitter configured to transmit radar at a target; an aperture including an array of physically independent airborne carriers, each of the carriers configured to receive radar echoes from the target; and a base station, which may be located at ground level, in communication with each of the airborne carriers to receive the radar echoes and determine an image of the target from the received radar echoes.
摘要:
The present invention relates to a vehicle radar system that comprises transmitting means arranged for generating and transmitting FMCW, Frequency Modulated Continuous Wave, chirp signals. A first and second transmitter antenna arrangement are arranged to transmit a respective first and second chirp signal. The radar system comprises receiving means, and an Analog to Digital Converter, ADC, arrangement. The receiving means is arranged to receive reflected signals and to mix them with at least one chirp signal and the ADC arrangement is arranged to digitize the mixed signals. The radar system further comprises a signal modulator arranged to modulate the second chirp signal by applying a predetermined pattern of phase shifts and/or amplitude shifts to the second chirp signal. The first chirp signal is constituted by the modulated second chirp signal. The present invention also relates to a corresponding method.
摘要:
An algorithm for deriving improved navigation data from the autofocus results obtained from selected image blocks in a wide-beam synthetic aperture radar (SAR) image. In one embodiment the navigation error may be approximated with a vector of low-order polynomials, and a set of polynomial coefficients found which results in a good phase error match with the autofocus results. In another embodiment, a least squares solution may be found for the system of equations relating the phase errors at a point in time for selected image blocks to the navigation error vector at that point in time. An approach using low sample rate backprojection (150) initially to select suitable image blocks, and full sample rate backprojection (156) for the selected image blocks, followed by full sample rate backprojection (164) for the image, using the improved navigation solution, may be used to reduce the computational load of employing the algorithm.
摘要:
Die Erfindung betrifft ein Verfahren zur rechnergestützten Verarbeitung von SAR-Daten, welche von einem SAR-Radarsystem (SA1, SA2) zur Fernerkundung der Erdoberfläche stammen, das zumindest einen Sender und zwei Empfänger umfasst. Bei der Bewegung des SAR-Radarsystems (SA1, SA2) in eine Azimut-Richtung (x) werden oder wurden die Radarechos von durch den zumindest einen Sender ausgesendeten und an der Erdoberfläche reflektierten Radarpulsen (RP) durch die zwei Empfänger empfangen, wodurch für den einen Empfänger eine erste Datenakquisition (DA1) erhalten wird, welche für eine Vielzahl von Azimut-Positionen in der Azimut-Richtung (x) jeweils erste Tastwerte (d m ) für mehrere Range-Positionen in einer zur Azimut-Richtung (x) senkrechten Range-Richtung (y) umfasst. Für den anderen Empfänger wird eine zweite Datenakquisition (DA2) erhalten, welche für eine Vielzahl von Azimut-Positionen in der Azimut-Richtung (x) jeweils zweite Tastwerte (d s ) für mehrere Range-Positionen (y) in einer zur Azimut-Richtung senkrechten Range-Richtung umfasst, wobei die erste und zweite Datenakquisition (DA1, DA2) zumindest teilweise das gleiche Gebiet der Erdoberfläche überdecken. Das erfindungsgemäße Verfahren zeichnet sich dadurch aus, dass im Falle von einem oder mehreren fehlenden ersten Tastwerten (d m ) eine geometrische Rekonstruktion (GR) für einen jeweiligen fehlende ersten Tastwert (d m ) durchgeführt wird, bei welcher der jeweilige fehlende erste Tastwert (d m ) aus vorhandenen zweiten Tastwerten (d s ) mit Positionen in der zweiten Datenakquisition (DA2) rekonstruiert wird, welche Reflexionspositionen auf der Erdoberfläche von Radarechos entsprechen, die zum fehlenden ersten Tastwert (d m ) beitragen, wodurch ein dritter Tastwert (d m,GR ) erhalten wird, wobei der dritte Tastwert (d m,GR ) oder ein aus dem dritten Tastwert (d m,GR ) abgeleiteter Tastwert den fehlenden ersten Tastwert (d m ) ersetzt.
摘要:
A method of synthetic aperture radar autofocus for ground penetration radar (100). The method includes transmitting a signal via an antenna (102); receiving a reflected signal comprising a plurality of image blocks via the antenna (102); reading each image block from the reflected signal (602) via a processor (108); locating prominent targets in each image block (604) via the processor (108); estimating ground penetration phase error (606) via the processor (108) in each image block via phase error inputs (608) including pulling range and quantization level by generating a 1 D phase error (706) and converting the 1 D phase error into a 2 D phase error of an image spectra (708); refocusing each image block according to estimated ground penetration phase error for that image block (610) via the processor (108); and forming an image mosaic comprising each refocused image block (614) via the processor (108).
摘要:
La présente invention concerne un procédé d'élimination d'échos parasites en imagerie SAR comprenant une étape Etp1 de définition des paramètres d'imagerie SAR, une étape Etp2 de calcul du spectre du signal reçu, dans chaque case distance, d'une zone d'intérêt 51, une étape Etp3 de filtrage des spectres dans chaque case distance, une étape Etp4 de formation d'imagette SAR 51 et une étape Etp5 de concaténation des imagettes SAR 51 pour former l'image SAR finale.
摘要:
Methods and apparatus for providing a first radar system having a transmitter and a receiver and a reflector to provide a synthetic aperture radar relationship. The signal return is processed to generate an image of targets in the area.