oa Future Satellite Based Sensors For Radio Remote Sensing Of Low-Latitude Irregularities

The equatorial and high-latitude ionosphere has long<br>been known to be the primary source of amplitude<br>and phase fluctuations for VHF, UHF, and L-Band<br>radio waves. A new approach for monitoring<br>ionospheric irregularities that affect radio propagation<br>is being implemented using radio beacons and<br>receivers on satellites in low-earth-orbit (LEO).<br>These system called Coherent Electromagnetic Radio<br>Tomography (CERTO) uses three frequency radio<br>beacons operating at VHF (150.012 MHz), UHF<br>(400.032), and L-Band (1066.752 MHz). Receivers<br>located on the ground and on other satellites record<br>the phase differences between a pair of frequencies.<br>This differential phase data is used to determine the<br>integrated electron density along oblique and vertical<br>paths using satellite to ground geometry and along<br>both vertical and horizontal paths using satellite-tosatellite<br>observations.