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AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorPeter F. MacDoran
Estimating the term…
The columnar electron content of the ionosphere between a spacecraft (10) and a receiver (12, 14) is measured in realtime by cross correlating two coherently modulated signals transmitted at different frequencies (L.sub.1, L.sub.2) from the spacecraft to the receiver using a cross correlator (16). The time difference of arrival of the modulated signals is proportional to electron content of the ionosphere. A variable delay (21) is adjusted relative to a fixed delay (20) in the respective channels (L.sub.1, L.sub.2) to produce a maximum at the cross correlator output. The difference in delay required to produce this maximum is a measure of the columnar electron content of the ionosphere. A plurality of monitoring stations (31, 32, 33) and spacecrafts (GPS satellites 34, 35, 36) are employed to locate any terrestrial event that produces an ionospheric disturbance.
A method of calibrating the electron columnar content in the space between a transmitter on a spacecraft and a receiver on Earth comprising the steps of:
Apparatus for calibrating the electron columnar content between a transmitter in space and a receiver on Earth comprising
A system for detecting the occurrence of a terrestrial event that disturb the ionosphere by monitoring electron content of the ionosphere using a plurality of stations and spacecrafts at known locations, each station operating the same as all other stations with signals received from a spacecraft, comprising
Dependencies are inferred from the claim text.