ConGaLSAR: A Constellation of Geostationary and Low Earth Orbit Synthetic Aperture Radar

Xiao, Peng; Liu, Bo; Guo, Wei

doi:10.1109/lgrs.2019.2962574

Cited by 17 publications

(14 citation statements)

References 9 publications

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“…At the high altitude of geostationary orbits, passive microwave radiometer systems cannot provide the required spatial resolutions. However, recent developments in radar technology, particularly at X-and Ku-band frequencies (1-3 cm wavelength) provide an excellent opportunity for relatively high-spatial resolution observations from a geostationary platform(Rodríguez et al, 2019;Xiao et al, 2020). Alternatively, a collection of smallsats (cubesats or other similar size classes) with different daily observation times could also potentially achieve the required temporal and spatial resolution (e.g., the Capella Space constellation(Stringham et al, 2019)).…”

mentioning

confidence: 99%

Detecting forest response to droughts with global observations of vegetation water content

Konings

Saatchi

Frankenberg

et al. 2021

Global Change Biology

104

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mentioning

confidence: 99%

Detecting forest response to droughts with global observations of vegetation water content

Konings

Saatchi

Frankenberg

et al. 2021

Global Change Biology

104

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“…On the other hand, [146] evaluated the performance of the LT-1's synchronization scheme for multipath effects, and [147] presents its experimental verification. 3) ConGaLSAR: A Constellation of Geostationary and LISA SAR (ConGaLSAR) radars has been proposed in [136]. The phase and time synchronization of this constellation would be supported by a novel transponding mode known as MirrorSAR, where the LISA satellites work as relay nodes for the ground echoes to the illuminating GEO satellite.…”

Section: ) Argos: the Advanced Radar Geosynchronous Ob-mentioning

confidence: 99%

Architectures and Synchronization Techniques for Distributed Satellite Systems: A Survey

Marrero¹,

Duncan²,

Querol³

et al. 2022

Preprint

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CDSS is a key enabling technology for the future of remote sensing and communication missions. However, they have to meet strict synchronization requirements before their use is generalized. When clock or local oscillator signals are generated locally at each of the distributed nodes, achieving exact synchronization in absolute phase, frequency, and time is a complex problem. In addition, satellite systems have significant resource constraints, especially for small satellites, which are envisioned to be part of the future CDSS. Thus, the development of precise, robust, and resource-efficient synchronization techniques is essential for the advancement of future CDSS. In this context, this survey aims to summarize and categorize the most relevant results on synchronization techniques for DSS. First, some important architecture and system concepts are defined. Then, the synchronization methods reported in the literature are reviewed and categorized. This article also provides an extensive list of applications and examples of synchronization techniques for DSS in addition to the most significant advances in other operations closely related to synchronization, such as inter-satellite ranging and relative position. The survey also provides a discussion on emerging data-driven synchronization techniques based on ML. Finally, a compilation of current research activities and potential research topics is proposed, identifying problems and open challenges that can be useful for researchers in the field.

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“…The typical system parameters of ConGaLSAR are shown in Table I. As discussed in [1], the azimuth resolution of stripmap mode is approximately equal to the diameter of receiving antenna on transponder with an effective azimuth bandwidth about 2800 Hz. Because the transmitter and receiver do not use the same antenna hardware, the transmitting pulse occlusion is unnecessary to be considered.…”

Section: A System Descriptionmentioning

confidence: 99%

“…ONGALSAR is a novel short revisiting multi-static SAR system, which contains one geostationary illuminator and dozens of low Earth orbit (LEO) transponders [1]. With MirrorSAR technology [2]- [4], ConGaLSAR gives an economical way to construct a constellation with 3 m resolution and 72 min averaging revisiting interval while ensuring time and frequency synchronizations.…”

Section: Introductionmentioning

confidence: 99%

A Comprehensive Method of Ambiguity Suppression for Constellation of Geostationary and Low Earth Orbit SAR

Xiao

Guo

et al. 2020

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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ConGalSAR is a novel SAR constellation which has outstanding performance of revisit and economy. In the system, with MirrorSAR technology, one geostationary illuminator and several economical low Earth orbit transponders work together to achieve short revisiting interval. Because of the huge difference in the distances of transmitting and receiving, the spatial weighting of the antenna patterns on the ground are quite different, which leads to the deterioration of ambiguity to signal ratio. Multiphase center and digital beam forming antennas can suppress the ambiguity energy; however, they are too expensive and heavy to be equipped on the dozens of transponding nano-satellites. In this article, a comprehensive ambiguity suppression method including reflector antenna design and signal processing is proposed to reduce the ambiguity ratio, which well solves the ambiguity problem under the condition of low manufacturing costs and lightweight transponders. In terms of hardware design, the multifeed reflector antenna is applied on the transponder, in which the feeds receive echo together. Based on this, the low sidelobes beamforming is achieved to well suppress the ambiguity. Meanwhile, amplitude-modulated chirps are also used here aiming at the residual ambiguity in the large dynamic scene. Through spectral selection and extrapolation processing, range ambiguity energy is suppressed more while preserving the resolution. Digital simulations show that the comprehensive method can realize-20 dB ambiguity ratios at least, which conforms to ambiguity-to-signal ratio design of ConGaLSAR.

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ConGaLSAR: A Constellation of Geostationary and Low Earth Orbit Synthetic Aperture Radar

Cited by 17 publications

References 9 publications

Detecting forest response to droughts with global observations of vegetation water content

Detecting forest response to droughts with global observations of vegetation water content

Architectures and Synchronization Techniques for Distributed Satellite Systems: A Survey

A Comprehensive Method of Ambiguity Suppression for Constellation of Geostationary and Low Earth Orbit SAR

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