(U) Phillips Lab has developed a real-time warning system to provide information on scintillation. The system acquires a 250 MHz signal from a satellite and processes the data to produce a report of scintillation conditions. A user can call an automated telephone answering system to receive voice messages of on-going scintillation activity on MILSATCOM links. The capability will be increased to frequencies that affect GPS satellites. In the far-term, a dedicated equatorial scintillation satellite would provide satellite communicators with a real-time measurement of ionospheric scintillation and allow them to take immediate actions to minimize signal fading effects.
(U) The National Environmental Monitoring Satellite System (NEMSS) concept includes plans for a dedicated scintillation satellite. The scintillation satellite would also follow-on or augment the C/NOF system.
(U) Ionospheric scintillation interrupts surveillance, communications, and navigation systems by severely attenuating UHF and L-band transmissions. Scintillation is a phenomenon characterized by rapid fluctuations of signal amplitude and phase caused by electron density variations associated with ionospheric disturbances. Complete transmission loss can occur and can last more than six hours after sunset over large regional areas near the magnetic equator (such as South America, The Persian Gulf, India, and Taiwan). Scintillation is caused by fluctuations in the ionosphere, and is unrelated to solar activity; however, severe solar activity can increase its effects. Some scintillation also occurs over the polar caps and under the auroral oval at all local times.
(U) To be supplied.
|SCINDA||Scintillation Network Decision Aid (SCINDA)|
|Space-Based Sensors||Space Based Sensors|
|ENVIRONMENTAL MONITORING||SPACE FORCE ENHANCEMENT: ENVIRONMENTAL MONITORING|
(U) National Security Space Road Map Team, NSSA, Open Phone: (703) 808-6040, DSN 898-6040.
(U) 21 November 1997
(U) Road Map Production Date: 23 June 2001