Baptiste Guillot, Safran Data Systems; François Thevenot, Safran Data Systems; Sébastien Herbiniere, Safran Data Systems; Thierry Balanche, Safran Data Systems
Keywords: Passive RF, TDOA, FDOA, LEO, non-GSO, SSA, SDA, SAFRAN, sensor, daylight, passive radar, passive ranging, IOD
Abstract:
The rapid growth of Low Earth Orbit (LEO) satellite constellations, particularly in the areas of global communications and Internet services, has underscored the critical need for accurate, global tracking of these assets. This presentation examines the implementation of passive RF tracking systems for LEO satellites, developed and operated by SAFRAN, with a focus on both the performance analysis of the technology and its complementarity with other Space Situational Awareness (SSA) methods. We begin by outlining the challenges of designing and integrating a reliable tracking system for LEO satellites, including the deployment and ongoing maintenance of a global sensor network of over 100 strategically placed antennas.
In the second section, we provide a detailed explanation of the passive RF (Radio Frequency) tracking technology, emphasizing its unique ability to track satellites without emitting any signals, which significantly reduces the risk of detection and interference. This capability makes passive RF particularly well-suited for security-sensitive applications, where stealth and resilience are paramount. In addition, unlike traditional tracking methods, passive RF tracking is not affected by daylight or adverse weather conditions, enabling continuous and reliable measurements as soon as the targeted satellite emits a signal and is within the sensor’s line of sight.
The third section focuses on the means and methods used by SAFRAN in the measurement process. This is followed by a comprehensive analysis of the results obtained by tracking reference satellites. The analysis covers the raw measurement accuracy and the orbit determination accuracy, providing a clear assessment of the precision and reliability of the system. These results demonstrate the robustness of the system, which is critical for both commercial and defense applications. We also investigate the use of passive RF tracking to monitor large satellite constellations, such as OneWeb, highlighting its potential for continuous global monitoring and enhancing operational security in densely populated satellite environments.
Finally, the presentation concludes with a discussion of the growing importance of passive RF tracking in the context of defense and space security. In addition to precise tracking, passive RF technology provides valuable insights into satellite behavior, that can contribute to early detection of anomalies. For example, analysis of the RF transmission patterns can provide information on the health of the satellite, while power level patterns can help characterize the satellite’s attitude, allowing potential failures to be detected from the ground. Looking ahead, the future of passive RF sensor offers significant opportunities for space safety by helping to detect and characterize unknown objects with an optimized uncued search approach.
Date of Conference: September 16-19, 2025
Track: SDA Systems & Instrumentation