The objective of the activity is to develop and test a radio frequency air interface for joint satellite communication and RF sensing purposes in a representative system scenario and a commonly selected frequency band. A test-bed will be used to evaluate the ranging accuracy and achievable throughput without degradation of the communication channel. Targeted Improvements: Enabling the use ofthe communication channel also for RF sensing applications and conversely enabling the use of frequencies allocated for ranging/sensing to be used for communication. Description: The re-usability of radio frequency spectrum along with transmitter and receiver infrastructure on-board and on-ground have made the coexistence of satellite communication and remote sensing (such as ranging, detection and object identification) an active area of research and development. This activity will develop and test a radio frequency air interface for joint satellite communication and RF sensing purposes in a representative system scenario. In particular, the followingtechnical challenges in the end-to-end system design shall be addressed: the design of transmitters and receivers that reach the required accuracy for remote sensing while minimising the impact on the communication link throughput, the design of an air interface that allows measuring accurately signal characteristics at the receiver (such as timing, phase, etc.) for remote sensing while maintaining a high spectral efficiency for communications, full-duplex operation with a capability of continuous transmission and reception for remote sensing applications.The performance of the joint air interface design in terms of critical parameter estimation accuracy as well as achievable communication throughput shall be compared with the results based on the opportunistic signals (such as existing open standard solution including DVB-S2X or existing 3GPP signals). The outcome of the activity will serve as a benchmark and the new standard shall servicing both remote sensing and communication services. The use of existing communication air interfaces such as DVB-S2X for remote sensing have been reported by research teams which can serve as the starting point for the proposed activity.