Polarimetric Ground-to-Ground and Ground-to-Air Channel Characterization in Forest Environment
Résumé
The precise localization of an injured person in a forest environment can be made owing to his cell phone by deploying a dedicated direction finding equipment in the search zone and placed onboard either a vehicle or a drone. The localization accuracy being strongly dependent on the propagation channel characteristics, measurements have been carried out with a MIMO channel sounder at a center frequency of 1.35 GHz and with an 80 MHz bandwidth. Each array element is a dual-polarized patch antenna allowing a multidimensional polarimetric estimation of the channel. The receiving array is below or over the canopy when onboard a vehicle or at different altitudes when onboard a drone. Path loss, delay spread and coherence bandwidth are studied for different relative orientations of the antennas, including co-and cross-polarization configurations. Directions of arrival of the rays are deduced from the MIMO matrix owing to a high resolution algorithm.