RADARSAT elevation antenna pattern determination

Lukowski, T.I.; Hawkins, Richard A.; Cloutier, Claudette; Wolfe, John; Teany, L.D.; Srivastava, Satish K.; Banik, B.T.; Jha, RM; Adamovic, M.

doi:10.1109/igarss.1997.606453

Cited by 13 publications

(4 citation statements)

References 3 publications

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“…Radiometric Accuracy performance is tracked by evaluating the deviations in the currently measured pattern compared to the stored calibrated pattern for any given beam, using images of the Amazon Rainforest (843 acquisitions to date). The methodology for elevation beam pattern measurements used for RADARSAT-1 beams has been described elsewhere [8]. Data are collected for each beam about once every two months, depending on cyclical availability of imaging opportunities over the Amazon Rainforest.…”

Section: Radiometric Calibration and Image Quality Performancementioning

confidence: 99%

RADARSAT-1 Image Quality Evolution to the Extended Mission

Ko¹,

Maldague²,

Page³

et al. 2004

Space OPS 2004 Conference

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Since its launch on November 4,1995 and the start of the routine operation on April 1, 1996, RADARSAT-1, the first Canadian SAR remote sensing satellite, is providing calibrated data to worldwide users for their intended applications. This paper discusses the calibration and image quality perspectives of RADARSAT-1 in its extended mission, as evolved from the earlier phases of the calibration plan. At the early qualification stages of the mission, the RADARSAT-1 calibration and image quality plan integrated two sets of measurements still in use today: both single beams and ScanSAR are monitored routinely using images of the Amazon Rainforest for calibration performance, and using images of RADARSAT-1 Precision Transponders for quality performance. Following the Antarctic Mapping Mission in 1997, systematic calibration measurements showed changes in the characteristics of several previously calibrated elevation antenna patterns. Compensations for these changes are made in the processor by re-calibrating the beams. In addition, a major upgrade of the ScanSAR processor completed at CDPF in 2002 made significant improvements in image quality and radiometry. Through the 2 years of successful image quality maintenance of RADARSAT-1 in extended mission, the provision of radiometrically and geometrically calibrated products to users by the Canadian Data Processing Facility (CDPF) has also fostered specific efforts to prevent image quality to be affected by aging and potential failure of spacecraft subsystems. In late October 2000, concerns began to rise of the possibility of failure of the Horizon Scanner 1, which would result in operating the spacecraft in a mode known as 'Attitude Determination Method 3' (ADM3), causing a decrease in attitude control performance of spacecraft compared to the current operation in ADM1.Experiments were conducted to better understand the impact on processing and image quality when in ADM3 mode. No major impact on image quality was noticed with adapted re-processing. In mid 2002, due to aging considerations for the On-Board Recorder, sites within Canadian mask have been envisioned for their ability to support radiometric analyses, as a potential alternative for the Amazon Rainforest, where images are recorded. From several sites, a Boreal Forest location near Hearst, Ontario, was chosen for testing radiometric measurements, using specific beams to cover the entire range of incidence angles. In parallel, new methods and software tools are developed to improve image quality operational efficiency and to perform new measurements. A database tool has been developed for tracking performance of image quality parameters and radiometric measurements over Amazon and Hearst regions. Downloaded by 128.70.15.31 on June 20, 2016 | http://arc.aiaa.org |

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Section: Radiometric Calibration and Image Quality Performancementioning

confidence: 99%

RADARSAT-1 Image Quality Evolution to the Extended Mission

Ko¹,

Maldague²,

Page³

et al. 2004

Space OPS 2004 Conference

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“…(a) Ground receiver method [6][7][8][9][10]. Several ground receivers are deployed in the SAR swaths area along the range direction with certain intervals.…”

Section: Introductionmentioning

confidence: 99%

An In-Orbit Measurement Method for Elevation Antenna Pattern of MEO Synthetic Aperture Radar Based on Nano Calibration Satellite

et al. 2022

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The medium-Earth-orbit synthetic aperture radar (MEO-SAR) is deployed at orbit altitude above low-Earth-orbit synthetic aperture radar (LEO-SAR, around 2000 km) and below the geosynchronous orbit SAR (GEO-SAR, near 35786 km) to cover a wide swath, which is four to five times larger than LEO-SAR. Therefore, the measurement method for the LEO-SAR elevation antenna pattern using the SAR data acquired over the Amazon tropical rainforest (ground-based method), where the typical width of rainforest area is approximately 150 km, can hardly meet the requirement of a wide swath to determine the MEO-SAR antenna elevation pattern. Moreover, several new MEO-SAR systems are now proposed that will use low frequency, and the low frequency penetration characteristics may affect the elevation antenna pattern determination using homogenous distributed targets such as the Amazon rainforest. This paper proposes a novel space-based method for the in-orbit measurement of the elevation antenna pattern of MEO-SAR based on one nano calibration satellite mounted with a receiver. Through appropriate orbit design, the nano calibration satellite can fly across the entire MEO-SAR swath along the range direction, and the elevation antenna pattern envelope can be extracted from the data recorded by the receiver. Simulation work is performed to verify the feasibility of the proposed space-based method, and the measurement accuracy of this method is analyzed.

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“…In order to quantify the SAR data, these spaceborne SARs have been tested on the antenna pattern on-orbit. Scientists have developed a complete series of on-orbit test methods to test the shape of antenna patterns, such as the standard reflector method [ 3 ], ground receiver method [ 4 , 5 ], ground transmitter method [ 6 , 7 ], and tropical rainforest uniform target method [ 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. As the number of beams increased, TerraSAR-X developed the antenna pattern measurement and verification method based on a mathematical model [ 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

An Accurate Measurement Method for Azimuth Pointing of Spaceborne Synthetic Aperture Radar Antenna Beams Based on Ground Receiver

Liang

Jia

Kang

et al. 2018

Sensors

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The paper proposes a new method for measuring the azimuth pointing of spaceborne synthetic aperture radar (SAR) antenna beams based on the ground receiver, which can receive and record complex sampling data of the pulse signals transmitted from the spaceborne SAR. The center of the antenna pattern is extracted from the complex sampling data amplitude envelope to obtain the time when the beam main lobe center irradiates the ground receiver, and the range migration information is extracted from the complex sampling data to obtain the time when the satellite is over the top of the ground receiver. The results of Chinese civilian remote sensing GaoFen-3 SAR satellite experiment data processing show that the measurement accuracy of this method is better than 0.002°, which can be applied to the accurate measurement of azimuth pointing of various low Earth orbit (LEO) SAR antenna beams.

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RADARSAT elevation antenna pattern determination

Cited by 13 publications

References 3 publications

RADARSAT-1 Image Quality Evolution to the Extended Mission

RADARSAT-1 Image Quality Evolution to the Extended Mission

An In-Orbit Measurement Method for Elevation Antenna Pattern of MEO Synthetic Aperture Radar Based on Nano Calibration Satellite

An Accurate Measurement Method for Azimuth Pointing of Spaceborne Synthetic Aperture Radar Antenna Beams Based on Ground Receiver

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