Analysis of Array Distortion in a Microwave Interferometric Radiometer: Application to the GeoSTAR Project

Torres, F.; Tanner, Alan; Brown, Shannon; Lambrigsten, B.H.

doi:10.1109/tgrs.2007.898093

Cited by 25 publications

(11 citation statements)

References 13 publications

(31 reference statements)

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“…The degree to which the error propagates in this method, however, is also sensitive to the distribution of the beacons. Furthermore, the recovered ∆z and ∆φ are strongly coupled, as also demonstrated in [29]. To account for this coupling, the expression (18) is generalised using covariance matrices.…”

Section: B Receiver Phase and Baseline Calibration Using Airborne Bementioning

confidence: 89%

Phase and Baseline Calibration for Microwave Interferometric Radiometers Using Beacons

Maghraby

Park

Camps

et al. 2020

IEEE Trans. Geosci. Remote Sensing

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Relative phase and amplitude calibration between individual receiving elements is one of the key challenges in interferometric microwave radiometry. For monolithic interferometers, e.g., the Microwave Imaging Radiometer with Aperture Synthesis (MIRAS) on board the Soil Moisture and Ocean Salinity (SMOS) mission, the calibration of these two parameters is accomplished by correlated noise injection, where a noise signal from a central noise source is distributed to multiple elements in phase, and any measured phase and amplitude differences can be measured and compensated. As new multi-satellite interferometers are being proposed, a new strategy capable of calibrating these errors between the free-flying antennas as well as any antenna position errors is required. In this work, a new calibration scheme is proposed which uses a set of microwave beacons in place of the central noise source, placed at known locations within the interferometer's field of view. The visibility function produced by these point-sources can be pre-calculated, and any errors between the calculated and the measured visibility samples can be attributed to the errors to be determined. Since the phase of the measured visibility is a function of phase and antenna position errors, this technique is capable of calibrating these two parameters simultaneously. Calibration equations for far-and near-field beacons are presented. Using these expressions, five interferometric calibration routines are proposed and examined for geostationary formation flight microwave radiometers. While this technique is ideal for multi-satellite interferometers with variable antenna positions, it is also applicable to monolithic interferometers that can undergo substantial array deformation.

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Section: B Receiver Phase and Baseline Calibration Using Airborne Bementioning

confidence: 89%

Phase and Baseline Calibration for Microwave Interferometric Radiometers Using Beacons

Maghraby

Park

Camps

et al. 2020

IEEE Trans. Geosci. Remote Sensing

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“…The visibility samples are then taken by interpolating the sampling pattern ( Fig. 8) within this map, and the effect of outof-plane deviation w is approximated as constant phase errors in the individual antennas as performed in [20]. The individual antenna voltage pattern F n and beamwidth are modeled after the horn antennas applied on the GeoSTAR demonstrator [16] linearly scaled to our 3λ separation such that = 0.211 sr. Circular symmetry is assumed for the beam about its boresight with no pointing errors and all antennas are identical.…”

Section: Simulating Array Performancementioning

confidence: 99%

A Novel Interferometric Microwave Radiometer Concept Using Satellite Formation Flight for Geostationary Atmospheric Sounding

Maghraby

Grubisic

Colombo

et al. 2018

IEEE Trans. Geosci. Remote Sensing

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For most Earth observation applications, passive microwave radiometry from the geostationary orbit requires prohibitively large apertures for conventional single-satellite platforms. This paper proposes a novel interferometric technique capable of synthesizing these apertures using satellite formation flight. The significance of such concept is in its capacity to synthesize microwave apertures of conceptually unconstrained size in space for the first time. The technique is implemented in two formation flight configurations: a formation of a single full-sized satellite with microsatellites and a formation of several full-sized satellites. Practical advantages and challenges of these configurations are explored by applying them to geostationary atmospheric sounding at 53 GHz, the lowest sounding frequency considered for future sounder concepts Geostationary Atmospheric Sounder, GeoSTAR, and Geostationary Interferometric Microwave Sounder. The two configurations produce apertures of 14.4 and 28.8 m, respectively, and a spatial resolution of 16.7 and 8.3 km, respectively, from the geostationary orbit. The performance of these interferometers is simulated, and the challenges identified are threefold. First, intersatellite ranging in micrometer-level precision is required. Second, the extremely sparse design suggests that further innovation is necessary to improve radiometric resolution. Third, the presence of long baselines suggests extreme decorrelation effects are expected. While the first requirement has already been demonstrated on ground, the other two remain for future research. This technique can be implemented at arbitrary microwave frequencies and arbitrary circular orbits, meaning it can also be applied to other geostationary applications, or to achieve unprecedented spatial resolution from lower orbits, or to extend the accessible frequencies into lower frequency radio waves.

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“…(1) 结构变形与误差对电性能的影响。关于星载天线阵面误差方面，WANG [65] 分析了天线典型机械误差和随机误差对天线电性能影响，并指出星载有源相控阵天线为了获得-10 dBi 平均副瓣电平，阵面误差须控制在 1%波长范围以内。OSSOWSKA 等 [66] 指出星载可展开有源相控阵天线阵面变形主要有三种--对称变形、非对称变形和随机变形(图 11)，并分析了三种变形对天线电性能的影响。 ZULCH 等 [67] 针对美国空军和 NASA 机构研制的低轨道 L 波段 1.25 GHz 的星载有源相控阵天线，分析了天线阵面变形对天线增益和对 GMTI 的影响。 (2) 电磁电路校准与补偿。TORRES 等 [68] 分析了振动和热变形对天线电性能的影响，并通过外部相位参考方法来校正阵元位置误差。PIERRO 等 [69] 分析了最大变形量为 10 cm 的阵面变形对中轨道星载可展开有源相控阵天线波形和 GMTI 的影响。针对结构变形补偿和校准技术，TAKAHASHI 等 [70] 对星载可展开有源相控阵天线发射升空时振动和在轨热振动导致的结构变形提出了一种补偿方法，即分三个阶段校准：初始校准、发射前校准和在轨校准，最后对每个阵元的相位误差进行补偿。LIER 等 [71] 针对星载 Ku 频段(17.3～17.8 GHz)有源相控阵天线阵面变形，提出了控制电路编码校准技术。 (3) 形状记忆与自动补偿。SONG 等 [72] 将一种形状记忆合金丝嵌入蜂窝结构体中，用于精密空间结构的热变形补偿。 MCWATTERS 等 [73] 针对星载可展开有源相控阵天线在轨热环境、自身产生的热量、卫星平台的振动和机械变形，提出了天线自动校准和计量系统的概念，用于纠正在轨过程中的相位误差和机械变形。PETERMAN 等 [74] [86] ，这是因为它具有如下特点：RF MEMS 不仅可以大幅缩小相控阵天线体积，还可减轻重量；由于 MEMS T/R 组件在低功耗方面表现突出，能减轻相控阵扫描阵列的散热问题，延长其寿命；相比于传统 T/R 组件，MEMS T/R 组件的插入损耗低，故仅需要一般相控阵中 25%～50%的 T/R 组件数量即可满足天线系统功能需要 [87] ；由于 MEMS 器件的高线性度、宽带性能和开关高隔离度的特点，应用 MEMS T/R 组件还能提高相控阵天线带宽、灵敏度以及降低瞄准误差。 [51] (图 22)、单轴卷开式展开结构(图 23)和双线轴展开结构(图 24) [90] 等三种展开机构形式。复杂的展开机构是确保天线系统能否正常工作的首选条件，因此应绝对保证展开机构的可靠性。 …”

Section: 国外研究现状国外主要从三个方面来研究星载阵列天线的结构设计。unclassified

Development of Spaceborne Deployable Active Phased Array Antennas

Wang¹

2016

JME

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Abstract：As the "eyes" and "ears" of the space communications, electronic countermeasures, navigation, environmental monitoring and other satellite systems, the spaceborne deployable active phased array antenna achieves a greater physical aperture through a deployable configuration, and implements the individual control of different spot beams using the electronic scan mode. It has been one of the key equipments in the areas of aerospace without the many drawbacks brought by the mechanical scan antennas. The development process of the spaceborne active phased array antennas is introduced. And the configuration styles, performance requirements and engineering applications of the spaceborne deployable active phased array antennas are presented. The international research statuses are described. At the same time, a concise analysis of the seven key technologies of antenna structure field is made.The develop trends of the spaceborne deployable active phased array antenna structural technologies are discussed.

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Analysis of Array Distortion in a Microwave Interferometric Radiometer: Application to the GeoSTAR Project

Cited by 25 publications

References 13 publications

Phase and Baseline Calibration for Microwave Interferometric Radiometers Using Beacons

Phase and Baseline Calibration for Microwave Interferometric Radiometers Using Beacons

A Novel Interferometric Microwave Radiometer Concept Using Satellite Formation Flight for Geostationary Atmospheric Sounding

Development of Spaceborne Deployable Active Phased Array Antennas

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