REAL TIME IONOSPHERIC REFRACTION CORRECTION

REAL TIME INFORMATION OF IONOSHPHERIC PARAMETERS HAS BOTH MILITARY AND SCIENTIFIC USES. WE PROPOSE THE DEVELOPMENT OF A LOW COST DEVICE THAT CONTINUOUSLY TRACKS THE O- ADN X-MODE CRITICAL IONOSPHERIC FREQUENCIES WITH A 1 SECOND TIME RESOLUTION AND A 5 KHZ FREQUENCEY RESOLUTION. THE RESULTS ARE DISPLAYED IN REAL TIME IN DIGITAL FORMAT. THE CRITICAL FREQUENCY TRACKER" (CFT) TRANSMITS TWO WAVES (O- AND XX-MODE) AT ADJUSTABLE FREQUENCIES AND DETERMINES THE HIGHES FREQUENCY FOR WHICH THERE IS AN IONOSHPHERIC ECHO. AVERAGE TRANSMITTED POWER IS LESS THAN 20W. A BISTATIC VERSION OF THE CFT WILL YIELD REAL TIME READOUT OF THE MAXIMUM USEABLE FREQUENCY (MUF) FOR AN IONOSPHERIC PROPAGATION PATH. THE CFT MAY ALSO YIELD INFORMATION ON THE HEIGHT OF THE F2 PEAK IN THE IONOSHPER. WE SUGGEST THAT, WHEN A CFT IS AVAILABLE, IT IS POSSIBLE (BY COMBINING ITS INFORMATION WITH DATA FROM A VHF POLARIMETER) TO DEVELOP A SCHEME THAT PERMITS THE RAPID CALCULATION OF IONIZATION PROFILES USEFUL IN THE REAL TIME CORRECTION OF RADAR AIMING ERRORS OWING TO IONOSPHERIC REFRACTION.