Embedding the Localization and Imaging Functions in Mobile Systems: An Airport Surveillance Use Case

Driven by the extended applications and scarce spectrum resources, integrating the radio sensing functions into the future mobile system has been a consensus between the stakeholders. This paper demonstrates the feasibility of joint localization and imaging functions by exploiting the reference signal in the radio frame defined in the mobile system. Essentially, the subspace-based algorithms are adopted to jointly estimate the angle and distance and to enable the localization function for uplink and downlink signals and the derivation of theoretical performance boundaries. The vector antenna and virtual array concepts are introduced in the downlink scenario to enhance the angle estimation resolution. The uplink sounding reference signal is exploited to enable the imaging function as analog to synthetic-aperture radar (SAR). The joint localization and imaging performances are verified with a realistic ray-tracing channel based on the 3D ground and buildings model of Muret airport in France. The simulation results show that the reference signal can provide acceptable localization accuracy and target-distinguishing capability by adopting a virtual array and joint time-spatial smoothing in downlink and uplink, respectively. The joint localization and imaging results prove that the future mobile network is potentially a viable infrastructure to provide economic surveillance solutions for airports, particularly for secondary airports that are not well equipped with dedicated surveillance systems.