PASSIVE DETECTION OF SPORADIC-E USING GPS PHASE MEASUREMENTS

A passive sporadic E detection technique based on a Global Positioning System (GPS) receiving system has been developed and tested in a midl atitude environment. This system detects the small-scale total electro n content (TEC) variations believed to be produced by electron density structures associated with sporadic E. The current GPS detection tech nique was able to detect ionosonde-detected sporadic E conditions for 73% of the cases at high-elevation look angles in a set of midlatitude summer observations. Several approaches have been identified that may significantly improve this detection ratio. These approaches include reducing GPS phase multipath, implementing time and space averaging, a nd investigating the use of high-speed GPS TEC measurements. This tech nique provides a basic sporadic E detection functionality for applicat ions where an ionosonde is not available. It also provides complementa ry ionospheric information in regions outside the ionosonde viewing ar ea for applications where an ionosonde is available.