Deutsches Zentrum Fur Luft-und Raumfahrt E.v.

Deutsches Zentrum Fuer Luft-und Raumfahrt E.v

Alberto Moreira

Gerhard Krieger

Josef Mittermayer

Michelangelo Villano

Nicolas Gebert

Rolf Scheiber

Sigurd Huber

Jens Reimann

Marwan Younis

Pau Prats

Andreas Reigber

Patrick Klenk

Felipe Queiroz De Almeida

Francisco Lopez-Dekker

Prats-Iraola Pau

Mariantonietta Zonno

Ulrich Steinbrecher

Paco López-Dekker

Pau Prats-Iraola

Thomas Kraus

Marc Rodriguez-Cassola

A synthetic aperture radar method for remote sensing of the surface of the Earth by means of a radar device on a flying object moving in an azimuth direction above the surface of the Earth, wherein the radar device includes an array of antenna elements for transmitting radar pulses in a transmitting operation and for receiving radar echoes of these radar pulses reflected at the surface of the Earth in a receiving operation. A calibration mode is carried out in which

Synthetic aperture radar method and synthetic aperture radar device

The present disclosure relates to a method for computer-implemented processing of SAR raw data, which comprises radar echoes from radar pulse. An interference radar echo and an interference pulse are associated with a respective radar pulse, wherein the interference pulse and the respective radar pulse have orthogonal waveforms. SAR raw data are focused by a first focusing on the interference pulses including a range compression and an azimuth compression, to obtain first focused data, where a filtering is used for the range compression of a respective radar pulse, which filtering is matched to the waveform of the associated interference pulse. Thereafter, the first focused data undergo a signal suppression, which at least partially suppresses the interference radar echo, as a result of which second focused data are obtained. These second focused data finally undergo a defocusing including range decompression and azimuth decompression to obtain modified SAR raw data.

Method and apparatus for computer-assisted processing of SAR raw data

Sub-aperture processing is carried out. Within each sub-aperture, range compression and a correction for the target range variation are carried out. Baseband azimuth scaling is used for processing the azimuth signal, wherein a long azimuth reference function and thus a wide azimuth dimension are prevented. The scaling range is not constant and depends on the range, which is not equal to the original range vector. It is calculated such that, in combination with a subsequent derotation step, constant azimuth scanning is achieved for all ranges. The selected derotation function, which is applied in the azimuth time domain, makes it possible for all the targets to be in base band, in this way varying the effective chirp rate. Since the phase is purely quadratic because of the azimuth scaling step, it is thus possible to use an optimal filter which takes account of the effective chirp rate. IFFT results in a focused image, and a final phase function in the time domain allows phase maintenance. Application for SAR, SONAR and seismic raw data processing in the TOPS mode, as well as other modes which make use of the antenna polar diagram being scanned in the azimuth and/or elevation direction.

Method for processing TOPS (terrain observation by progressive scan)-SAR (synthetic aperture radar)-raw data

The transmission antenna () of the high-resolution synthetic aperture side view radar system comprises a plurality of sub-apertures (). In each individual transmission pulse, said sub-apertures are controlled in such a manner that a spatiotemporally non-separable multi-dimensional high-frequency waveform is produced as an transmission signal pulse form, such that the modulation of each transmission pulse has a spatiotemporal diversity which is not described by the product having functions which are independent from each other and which are dependent on, respectively, only one spatial dimension. The thus produced transmission pulse form is combined to a capture-sided spatial filtering by means of digital beamforming adapted to said transmission signal pulse form.

High-resolution synthetic aperture side view radar system used by means of digital beamforming

By means of tomograhic radar technique consisting of a coherent combination of large numbers of synthetic aperture radar images acquired by several air or space SAR systems having different look angles, a real three-dimensional imaging of volume scatterers is achieved. This allows the separation of the backscattered signal of volume scatterers in the height direction which can be further evaluated independently. The invention can be put to use in the three-dimensional analysis of vegetation layers and ground strata, but also for imaging and mapping of buildings, urban areas and mountainous terrain.

Airborne or spaceborne tomographic synthetic aperture radar (SAR) method

For interferometric and/or tomographic remote sensing by means of synthetic aperture radar (SAR) one to N receiver satellites and/or transmitter satellites and/or transceiver satellites with a horizontal across-track shift the same or differing in amplitude form a configuration of satellites orbiting at the same altitude and same velocity. Furthermore, a horizontal along-track separation, constant irrespective of the orbital position, is adjustable between the individual receiver satellites. In this arrangement one or more receiver satellites orbiting at the same altitude and with the same velocity are provided with a horizontal across-track shift varying over the orbit such that the maximum of the horizontal across-track shift occurs over a different orbital position for each satellite, the maxima of the horizontal across-track shifts are positioned so that the baselines are optimized for across-track interferometry. A transmitter or transceiver satellite is positioned either separate from the configuration without across-track shift or as part of the configuration with horizontal across-track shift.

Satellite configuration for interferometric and/or tomographic remote sensing by means of synthetic aperture radar (SAR)

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Olching, Germany

Alberto Moreira