Multiple Radar Propagation Modes Measured by the VHF SIMONe Norway System During Active Ionospheric Conditions

The Spread Spectrum Interferometric Multistatic meteor radar Observing Network (SIMONe) Norway systems were installed in August, 2021, and it was found that the number of measurements during active ionospheric conditions were consistently larger.  Through analysis of the 32.55 MHz continuous-wave (CW) pseudo-random phase modulated signal during an active period, many different propagation modes of the signal were isolated and investigated.  These include direct TX-RX groundwave, scattering from meteor trails, over-the-horizon (OTH) propagation from SIMONe Germany sites at a distance of ~ 1500 km, E-region coherent scatter, and groundscatter.  Three different multistatic links are presented with temporal and range resolutions on the order of 2 s and 1.5 km.  The angle of departure of the signals were determined through the use of multiple different codes transmitted at a distributed transmitter array, with a single receiving antenna at each of the sites.  The analysis of the signal is described, and the results highlight the capabilities of the SIMONe systems to investigate the lower thermosphere-mesosphere boundary region.