Air-ground channel measurements & modeling for UAS

Unmanned aircraft systems (UAS) are expected to be used in greatly increasing numbers in the near future. To safely integrate them into the national airspace system (NAS) requires reliable communication links. Since operating conditions and signaling rates of UAS will not always be identical to conventional civil piloted aircraft, the air-ground channel can become a challenging obstacle to reliable communications. Thus, along with NASA's Glenn Research Center we are conducting a measurement and modeling campaign to quantitatively characterize the air-ground channel. This paper describes our motivation, test system, measurement and modeling approach, and some initial results. Use of the developed models within larger network-scale investigations are planned, hence these results are a first step in the UAS integration into the NAS. Future results should be of use for any communication link performance analyses for UAS.