Multi-frequency satellite beacons and receivers for ionospheric irregularity imaging

Abstract

A new set of satellite radio beacons called the Coherent Electromagnetic Radio Tomography (CERTO) should be available in 2006 and 2007 for measurements of ionospheric total electron content and radio scintillations. The CERTO beacons transmit unmodulated radio waves at VHF, UHF and L-Band frequencies. A fixed ratio of 3/8 is used between successive frequencies. Total electron content (TEC) is obtained using the differential phase technique. The radio scintillation effects caused by diffraction when propagating through ionospheric irregularities are investigated over a wide frequency range with the CERTO transmissions. All of the CERTO beacons are in low earth orbit (LEO) with satellite inclinations ranging from 13 to 98 degrees. Each satellite that carries CERTO has other plasma sensors that complement the beacon data. In addition, a sCintillation and Tomography Receiver In Space (CITRIS) instrument will be launched in late 2006 to detect signals from the CERTO beacons and from the array of 56 DORIS VHF/S-Band radio beacons placed around the word by the French CNES. CITRIS will record ionospheric occultations and radio scintillations using a unique LEO geometry between satellites and between the ground and space. New algorithms have been developed for the multi-frequency CERTO and CITRIS data to provide TEC and scintillation data with greater accuracy than previously obtained with dual-band beacons. The data from the beacon receivers will be used to update space weather models.