LEO to GEO-SAR Interferences: Modelling and Performance Evaluation

Abstract

This paper proposes a statistical model to evaluate the impact of the signal backscattered by low Earth orbiting (LEO) synthetic aperture radar (SAR) and received by GEO-stationary orbiting SAR. The model properly accounts for the bistatic backscatter, the number of LEO-SAR satellites and their duty cycles. The presence of many sun-synchronous, dawn-dusk satellites creates a 24 h periodic pattern in interference that should be considered in the acquisition plan of future geostationary SAR. The model, implemented by a numerical simulator, allows also the prediction of performance in future scenarios of many LEO-SAR. Examples and evaluations are made here for X band.

Mitigation of Radio Frequency Interference in Synthetic Aperture Radar Data: Current Status and Future Trends

“…Long duration mutual interference that occurred between Sentinel-1 and the Canadian Radarsat-2 satellite, the Chinese GAOFEN-3 satellite has been reported and investigated [28]. This kind of terrain scattered interference would be more common for future geosynchronous synthetic aperture radar (GEO SAR) system with large imaging swath and frequent revisits, as well as for forthcoming SAR constellations with more frequent occurrences of orbit crossing [29].…”

“…For this case, the received RFI signal could not be regarded as a single point-like source anymore, since it undergoes a remodulation by the illuminated area. The estimates of the received RFI power is derived in detail in [29]. Figure 7 shows a TSI example in real measured C-band Sentinel-1 SAR data acquired in Italy in August, 2015.…”

Parasitic Surveillance Potentialities Based on a GEO-SAR Illuminator

“…While high inclination orbits would require very large antenna diameters (20-50 m) and several kW of transmitted power, low inclinations allow much lighter antennas (2-6 m diameter) and few kW or even less [6]. These factors could facilitate mission design using current technologies in terms of power and antenna reflectors [3,9], and, therefore, are the most promising to become operative.…”

“…In contrast to LEO-SAR systems, geosynchronous SAR (GEO-SAR) configurations could provide a permanent illumination of wide areas of the planet. Originally proposed in 1978 by Tomiyasu [1], the GEO-SAR concept has been studied for many years, exploring several aspects of the mission design, such as the coverage, orbit, atmospheric perturbation and impact of Radio Frequency Interference (RFI) [2][3][4][5][6][7][8][9].…”

“…Prompted by these good characteristics, in this work we investigate which types of applications can fruitfully be enabled by GEO-SAR signals. In particular, we refer to satellites operating on geosynchronous orbits with small eccentricity, which are gaining momentum due to their capability to provide a near-continuous imaging with relaxed requirements for the system design [9]. We introduce parasitic concepts based on the availability of the emitted signals on a wide area referring to three main scenarios: aerial, ground and maritime surveillance.…”