The TerraSAR-X Antenna Model Approach

Bachmann, Martin; Schwerdt, Marco; Bräutigam, Benjamin; Grafmuller, B.; Herschlein, A.; Álvarez-Perez, José Luis

doi:10.1109/inica.2007.4353949

Cited by 19 publications

(8 citation statements)

References 1 publication

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“…The given values state the maximal deviation between simulated and measured antenna pattern within the 3 dB main lobe of the beam. It can be seen, that the deviation fulfils the required limit of ±0.2 dB for all beams [5].…”

Section: Beammentioning

confidence: 56%

TerraSAR-X Antenna Calibration and Monitoring Based on a Precise Antenna Model

Bachmann

Schwerdt

Bräutigam

2010

IEEE Trans. Geosci. Remote Sensing

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The high flexibility and tight accuracy requirements of modern spaceborne SAR systems require innovative technologies to calibrate and process the SAR images. To perform accurate pattern correction during SAR processing, an antenna model can be used to derive the multitude of different antenna beams generated by active antenna steering. The application of such an antenna model could be successfully demonstrated for the TerraSAR-X mission, launched in 2007. The methodology and the results of the in-orbit verification with an achieved accuracy of better than ±0.2 dB is reviewed in this paper in detail showing its outstanding accuracy. Additionally, the results of the antenna pattern long term monitoring are described pointing out the high stability of the system Index Terms-Active antenna calibration, antenna modelling, TerraSAR-X calibration Flight direction / azimuth Range / Elevation Flight direction / azimuth Range / Elevation Uncorrected image After antenna pattern correction

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Section: Beammentioning

confidence: 56%

TerraSAR-X Antenna Calibration and Monitoring Based on a Precise Antenna Model

Bachmann

Schwerdt

Bräutigam

2010

IEEE Trans. Geosci. Remote Sensing

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“…The deviation of the shape within the main lobe is less than 0.15 dB. The results of the validation of the antenna model are described in [6]. The in-orbit verification will be performed by three selected beams with low, medium and high incidence angles.…”

Section: Antenna Model Verificationmentioning

confidence: 99%

“…Hence, a new, more efficient, and affordable calibration concept has been developed [3,4]. The key element of this calibration concept is a novel antenna model approach [4,6]. The TerraSAR-X antenna model is utilised for generating all reference antenna patterns and for beam optimisation.…”

Section: Introductionmentioning

confidence: 99%

Results from TerraSAR-X geometric and radiometric calibration

Bräutigam

Schwerdt

Bachmann

et al. 2007

IET International Conference on Radar Systems 2007

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As TerraSAR-X, due for launch in June 2007, will be an operational scientific mission with commercial potential, product quality is of crucial importance. The success or failure of the mission essentially depends on the calibration of the TerraSAR-X system ensuring the product quality and the correct in-orbit operation of the entire SAR system. This paper describes the calibration procedures for TerraSAR-X and the dedicated activities to be performed during the five months commissioning phase. Results from on-ground tests are discussed with respect to geometric and radiometric calibration of the TerraSAR-X system.

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“…Many modern spaceborne SAR systems rely on complex antenna systems to steer the radar beam [1,2], shape its pattern [3] or to generate several phase centers [4]. This is only feasible by applying sophisticated antenna models to predict the properties of the radiated electromagnetic field for the given control settings.…”

Section: Introductionmentioning

confidence: 99%

Precise Antenna Pointing Determination in Elevation for Spaceborne SAR Systems Using Coherent Pattern Differences

et al. 2019

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The precise determination of the SAR (synthetic aperture radar) antenna pointing is an essential task initially performed during the commissioning phase of a spaceborne SAR system and is permanently monitored during the whole mission life-time. Besides a correct illumination of the scene during data acquisition, antenna pointing is required for proper compensation of the radiation pattern for radiometric correction during SAR data processing. The Amazon rainforest is a well-established target area for antenna pointing estimation in elevation as proven by many past and current SAR missions. Several new SAR systems are now proposed which are using long wavelengths, i.e., L- and P-bands, which will be implemented using reflector-based antenna systems. These reflectors have, in contrast to planar phased array antennas, no completely rigid connection to the satellite body and, hence, a more volatile antenna pointing. Due to the huge dimensions of such reflector antennas required for the envisaged long wavelengths and the finite stiffness of the boom, the antenna pointing may change significantly along the orbit. Such variation cannot be tracked using the common Amazon rainforest approach only, as this measurement opportunity exists only at two positions along the orbit (ascending and descending). Here, the performance of an alternative technique is presented which mitigates the influence of the underlying SAR scene by employing two coherent SAR datasets acquired simultaneously with different antenna patterns. This allows the use of amplitude and phase information for pointing estimation. No assumption upon the homogeneity of the underlying scene is required and, hence, pointing estimation becomes feasible at nearly any point along the orbit. This paper outlines the technique, describes simulation results and presents outcomes from first experimental acquisitions performed with the TerraSAR-X satellite.

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The TerraSAR-X Antenna Model Approach

Cited by 19 publications

References 1 publication

TerraSAR-X Antenna Calibration and Monitoring Based on a Precise Antenna Model

TerraSAR-X Antenna Calibration and Monitoring Based on a Precise Antenna Model

Results from TerraSAR-X geometric and radiometric calibration

Precise Antenna Pointing Determination in Elevation for Spaceborne SAR Systems Using Coherent Pattern Differences

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