Portable Interference Monitoring
Detection System (PIMDS)

System Description

PIMDS is composed of commercially off-the-shelve (COTS) components that can detect and locate interference in the Global Positioning System L1 frequency (1575.42 MHz). The PIMDS is capable of interference detection in the GPS L2 (1226.7 MHz) and L5 (1176.45 MHz) frequencies with the addition of COTS direction finding antennas for these frequencies. Its maximum effective radio line of sight range on flat terrain is approximately 2 miles for detecting signals at a minimum level of approximately -112 dBm in the L1 band. The PIMDS can be operated unattended in a stand alone mode with its automated remote capability. The PIMDS can be operated while mobile on any standard vehicle on normal road or off-road conditions without requiring any vehicle modifications. The PIMDS can be handled and operated by one field specialist. The entire system is packaged in one rugged enclosure that weights approximately 50 lbs. and takes an average of 30 minutes to assemble, calibrate and be fully operational.

Production/Delivery Status:

33 PIMDS are required, 1 for each of the FAA's Systems Management Offices (SMO) maintaining the NAS. 29 PIMDS are in-service each requiring one COTS L1 GPS direction finding antenna. 1 COTS GPS L1 direction finding antenna was procured in 2000. 11 additional COTS GPS L1 direction finding antennas have been ordered in 2001. 12 PIMDS will be GPS interference detection and location capable by end of 2001. 5 additional PIMDS units will need to be procured during 2002 with their respective COTS GPS L1 direction finding antenna to provide 1 PIMDS unit to the remaining 4 FAA SMO offices without a PIMDS and one National Spare to be available from the National Operations Control Center (NOCC). The remaining 17 COTS GPS L1 direction finding antennas for PIMDS units without this antenna will also be procured in 2002.