Programmable ultrawideband signal generator for electromagnetic susceptibility testing

Under Phase I of the Defense Advanced Research Projects Agency (DARPA) Networking in Extreme Environments (NETEX) initiative, Multispectral Solutions, Inc. (MSSI) was tasked with the development of a general-purpose, ultrawideband hardware simulator capable of reproducing a wide variety of ultrawideband (UWB) waveforms. The simulator, with UWB outputs from baseband through millimeter wave, was to be used for the purpose of electromagnetic susceptibility testing of legacy military radio, radar, and positioning systems. The ultimate goal of this portion of the Phase I program was the quantitative determination of those UWB parameters (e.g., frequency, power, pulse rate, pulse shape, dithering, etc.) which had the least impact on the operational performance of legacy designs. This describes the development of the MSSI NETEX UWB simulator (BFP1000).     

Ultra wideband technology for aircraft wireless intercommunications systems (AWICS) design

Current intercommunications system (ICS) designs for military, multicrew aircraft utilize lengthy, encumbering cords to physically attach the crewmember's helmet or headset to a distributed audio intercom system. Typical ICS long-cords are approximately 100 feet in length and allow crewmembers to maintain communications as they move about the aircraft while performing their mission duties. These cords also allow crewmembers to maintain communications with the aircraft when disembarked, as when they are controlling aircraft during engine start-up. Unfortunately, the current wired topology significantly reduces mission effectiveness, impedes crewmember movement, and greatly increases the crewmember's risk of injury. These drawbacks are more pronounced onboard military rotary winged aircraft (helicopters) where several crewmembers have been injured or killed during emergencies requiring the aircraft to ditch at sea. During ditching, crewmembers often became entangled in their lengthy ICS cord, preventing or delaying aircraft egress. This paper discusses the development of an aircraft wireless intercommunications system (AWICS) which utilizes ultra wideband (UWB) technology to address mission requirements for these multicrew, military aircraft. UWB offers unique advantages in this application - multipath mitigation, low probability of detection, low probability of interference to onboard legacy systems, and high throughput in a multiuser environment.     

Oblique-incidence ionospheric soundings over Central Europe and their application for testing now casting and long term prediction models

After a first oblique-incidence ionospheric sounding campaign over Central Europe performed during the period 2003–2004 over the radio links between Inskip (UK, 53.5°N, 2.5°W) and Rome (Italy, 41.8°N, 12.5°E) and between Inskip and Chania (Crete, 35.7°N, 24.0°E), new and more extensive analysis of systematic MUF measurements from January 2005 to December 2006 have been performed. MUF measurements collected during moderately disturbed days (17 ? Ap ? 32), disturbed days (32 < Ap ? 50) and very disturbed days (Ap > 50), have been used to test the long term prediction models (ASAPS, ICEPAC and SIRM&LKW), and the now casting models (SIRMUP&LKW and ISWIRM&LKW). The performances of the different prediction methods in terms of r.m.s are shown for selected range of geomagnetic activity and for each season.