Survey of RF Communications and Sensing Convergence Research <s> B. COMMERCIAL FLIGHT CONTROL <s> Air traffic is continuously increasing worldwide, with both manned and unmanned aircraft looking to coexist in the same airspace in the future. Next generation air traffic management systems are crucial in successfully handling this growth and improving the safety of billions of future passengers. The Automatic Dependent Surveillance Broadcast (ADS-B) system is a core part of this future. Unlike traditional radar systems, this technology empowers aircraft to automatically broadcast their locations and intents, providing enhanced situational awareness. This article discusses important issues with the current state of ADS-B as it is being rolled out. We report from our OpenSky sensor network in Central Europe, which is able to capture about 30 percent of the European commercial air traffic. We analyze the 1090 MHz communication channel to understand the current state and its behavior under the increasing traffic load. Furthermore, the article considers important security challenges faced by ADS-B. Our insights are intended to help identify open research issues, furthering new interest and developments in this field. <s> BIB001 </s> Survey of RF Communications and Sensing Convergence Research <s> B. COMMERCIAL FLIGHT CONTROL <s> This work is devoted to the design of an analog transceiver for the Aeronautical Radio Navigation Services band (960 to 1215 MHz) as a required step to the exploitation of the Software Defined Radio concept in avionics. The integration of all the equipment operating in this band into a single piece of reprogrammable hardware minimizes the size, weight, power and cost (the so-called SWaP-C requirements) of avionic equipment, as well as it enables easy and fast transition towards a modernization of the Communications, Navigation and Surveillance standards. The main challenges of the design are: To provide the receiver with the dynamic range required by the Minimum Operational Performance Standards; to minimize the SWaP-C requirements by sharing a single High Power Amplifier for all the services specified in the title; and to establish a suitable duplexing technique that allows all the services to meet their operational goals. Along with this design, an operational study of the proposed multiplexing/duplexing schemes is carried out through software simulation, proving the feasibility of the proposed schemes and a small impact on the systems' capabilities. <s> BIB002
In commercial flight air traffic control, a joint sensingcommunications problem has been present for many decades. Radar-like functionality is desired for locating friendly aircraft, while communications with pilots is paramount to coordinating the flight of multiple aircraft near and around airports. Modern systems employ a Mode S beacon radar system, which combines an interrogating radar with a communications response  . In this sense, the Mode S commercial flight system can be thought of as a cooperative radar scheme, where targets respond to radar stimulus with information back to the radar. A related system is the automatic dependent surveillance-broadcast (ADS-B), in which complicit aircraft self-locate via satellite navigation and broadcast their position to allow ground controllers and other aircraft to track their location BIB001 . New software-defined systems are attempting to integrate these various systems to minimize circuitry and maximize flexibility BIB002 .