초록 ▼

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 (L1, L2) from the spacecraft to the receiver using a cross correlator (16). The time di

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 (L1, L2) 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 (L1, L2) 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.

대표청구항 ▼

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: transmitting from said transmitter two broadband signals separated in frequency, each coherently modulated by pseudorandom noise; receiving in a d

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: transmitting from said transmitter two broadband signals separated in frequency, each coherently modulated by pseudorandom noise; receiving in a direct path from said transmitter both of said signals at a receiver having two channels for obtaining said modulations on said two signals; and cross correlating the modulation of one received signal to the modulation of the other received signal to determine the phase difference between the modulation of said one received signal to the modulation of said other received signal as a measure of electron content in the space between the transmitter and receiver.