ISAC-Empowered LEO Constellation Networked Sensing: Challenges and Opportunities

The pursuit of seamless global coverage in sixth-generation (6G) mobile networks has driven the development of low earth orbit (LEO) constellation networks. In addition to communication, the emerging 6G applications, such as low-altitude economy and smart city, also require high-accuracy, large-scale, and continuous sensing. Integrated sensing and communication (ISAC) has emerged as a key enabler, which could empower LEO constellations with dual capabilities of communication and sensing. With the implementation of networked sensing in ISAC-empowered LEO constellations, the requirements of emerging 6G applications can be satisfied. This article presents a comprehensive overview of networked sensing in ISAC-empowered LEO constellations. We first introduce the concepts, sensing types, application scenarios, and payload enhancements. Then, we delve into critical technical challenges of networked sensing in ISAC-empowered LEO constellations and discuss the promising solutions tailored to the unique characteristics of LEO constellations, such as high mobility and long distances to the targets. Finally, we highlight future research trends to further promote the performance of ISAC-empowered LEO constellations.