Capability of a Ground-Based Passive Surveillance System to Detect and Track Spaceborne SAR in LEO Orbits

Abstract

Monitoring the Earth’s surface from the low Earth orbit (LEO) by synthetic aperture radar (SAR) provides meaningful information about a number of human activities such as the ecosystem, agriculture, and of course security matters. During its operation in LEO orbits, spaceborne SAR, at altitudes between 200 km and 2000 km, inherently emit electromagnetic signals toward the Earth’s surface. It has been experimentally verified that it is possible to detect and intercept spaceborne SAR signals at a distance of hundreds of kilometers by a single electronic support measure (ESM) non-comms sensor, placed on the Earth’s surface. The work described in this document is a follow-up to the paper and describes the principle of a new non-cooperative passive tracking method of spaceborne SAR carriers, tracked by four ground-based passive ESM non-comms sensors. These sensors used the time difference of arrival (TDOA) method in order to determine the current spaceborne SAR position in LEO orbits. Simulations were performed to assess the impact of ESM sensor configurations on the SAR’s signal interception and positioning error. The simulation results showed that the proposed method is sufficient to detect a spaceborne SAR position in LEO.