Real-Time Ionospheric Monitoring System Using the GPS
MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
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In satellite tracking using ground-based radars, an estimate of the total electron content TEC along the path to the satellite is required to measure accurately the range of the satellite. This estimate is necessary because the radar wave travels at a slower speed as it propagates through the ionosphere. The range error Delta R that is introduced is dependent on the radar frequency f and on the TEC along the propagation path, and can be expressed by where Ne is the local electron density and R is the radar range. The TEC can vary significantly with the time of day, geomagnetic activity, and look direction. A real-time synoptic ionospheric monitoring system has been developed using data acquired from a T14100 Global Positioning System GPS receiver for use at the Millstone Hill satellite-tracking radar. The T14100 GPS receiver can track up to four GPS satellites at any one time. Each GPS satellite transmits signals at two different L-band frequencies Ll 1575.42 MHz and L2 1227.6 MHz. ne TEC along the path to each satellite can be determined by combining both frequencies using the pseudorange and the integrated phase data. At Millstone, the TEC is measured every 3 s for each GPS satellite in view.
- Atmospheric Physics
- Navigation and Guidance
- Active and Passive Radar Detection and Equipment