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Concept Design of Near-Space Passive Radar for Ocean Remote Sensing

Wen-Qin Wang(1)

(1) Uni. of Electron. Sci. and Tech. of China, JianShe Road, Chengdu, Sichuan, 610054, Chengdu, China


To avoid the rapidly increased ocean disasters such as the massive 2004 Indian tsunami, which caused vast devastation along the coastal areas, revolutionary advances across a wide range of tsunami prediction technologies are required. It appears that recent advances in near-space technology may provide a solution to these problems. Even as good as they are, current spaceborne and airborne remote sensing sensors cannot provide a long-term persistence due to orbital mechanics and fuel consumption.

Fortunately, these requirements can be achieved by using near-space platforms [15]. Near-space defined as the region between 20km and 100km was a cultural blind spot – too high up for conventional aircrafts, but too low for LEO satellites. Once we step back from platform-based thinking and look at effects, near-space becomes intriguing – opening the doors for new remote sensing opportunities. Near-space can offer many new capabilities which are critical to the emerging remote sensing applications, but not accessible from orbiting satellites or maneuvering aircrafts.

An such, inspired by recent advances in near-space technology, this paper proposes firstly the concept of a new passive bistatic SAR system for ocean remote sensing. The novelty of this concept resides in that passive SAR receivers placed inside stationary near-space free-floaters in conjunction with the illuminators of opportunity, so that to provide continuous monitoring of various ocean disasters such as tsunamis and floods. Not constrained by the orbital mechanics of the satellite platforms or the high fuel consumptions of the airborne platforms, near-space can stay at a specific site almost indefinitely to provide a persistent coverage, because it is above the storms and jet stream. These advantages make near-space passive bistatic SAR potentially very suited for ocean disaster monitoring.

This paper details the role of near-space passive bistatic SAR as a sensor system for ocean remote sensing. The corresponding system models and signal processing algorithms are provided. It is shown that the novel use of near-space platforms can provide the solutions that were thought to be out of reach for ocean remote sensing scientists.


Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry