Abstract: A system and method for testing the integrity of signals incoming to a satellite navigation system. The method is implemented with an array of antenna elements, and a receiver connected to each antenna element. The receivers simultaneously and continuously make measurements on all tracked signals. Each receiver measures the carrier phase of an incoming signal. Based on the carrier phase differences between antenna elements and the distance between them, the azimuth and elevation of the signal source can be calculated. This measured angle of arrival can then be compared to an expected angle of arrival to determine if the signal source is legitimate. The system and method can be also applied to determining the angle of arrival of sources of interference, and to mitigating the effects of both illegitimate and interfering signals.

Abstract: A system and method for testing the integrity of signals incoming to a satellite navigation system. The method is implemented with an array of antenna elements, and a receiver connected to each antenna element. The receivers simultaneously and continuously make measurements on all tracked signals. Each receiver measures the carrier phase of an incoming signal. Based on the carrier phase differences between antenna elements and the distance between them, the azimuth and elevation of the signal source can be calculated. This measured angle of arrival can then be compared to an expected angle of arrival to determine if the signal source is legitimate. The system and method can be also applied to determining the angle of arrival of sources of interference, and to mitigating the effects of both illegitimate and interfering signals.

Abstract: A self locating device that uses GSM signals associated with GSM digital telephone base stations to determine its current location. The device uses GSM common channel signals to determine observed time differences between a local base station and at least two additional base stations. It also uses the common channel signals to identify these base stations and to match the identifications to geographical locations. It further uses a geolocation algorithm to determine the location of the device relative to the base stations, and uses the geographic location data to determine the current geographic location of the device.

Abstract: A method of using a GPS receiver to receive secondary data. A conventional GPS receiver is modified to receive such data, without modifying its hardware. The secondary data is carried in a signal that has the same characteristics as a conventional GPS navigation signal, but is delivered at a specified frequency and time and with a specified and “unused” spreading code. The secondary data is contained in a data subframe that is sufficiently similar to subframes that carry GPS navigation data, such that it can be demodulated and accessed by the GPS receiver.

Abstract: A method of using a GPS receiver to receive secondary data. A conventional GPS receiver is modified to receive such data, without modifying its hardware. The secondary data is carried in a signal that has the same characteristics as a conventional GPS navigation signal, but is delivered at a specified frequency and time and with a specified and “unused” spreading code. The secondary data is contained in a data subframe that is sufficiently similar to subframes that carry GPS navigation data, such that it can be demodulated and accessed by the GPS receiver.

Abstract: An autonomous stratospheric airship comprising a hull which contains an equipment bay, forward and aft ballonets, forward and aft air management sub-systems, a propulsion system, and a control system is described. The airship also comprises a regenerative solar energy power and storage sub-system which allows powered daytime and nighttime operations. Further, the control system of the airship enables autonomous operation between selected waypoints or along a specified line of sight. The solar arrays utilized by the airship are internally mounted and gimballed so as to provide maximum collection efficiency and not impede the aerodynamic profile of the airship. A greatly simplified and slightly less controllable version of the airship, which makes use of alternative solar array control and ballast management systems, while carrying the equipment bay on the exterior of the hull, is also disclosed.

Abstract: A self locating device that uses GSM signals associated with GSM digital telephone base stations to determine its current location. The device uses GSM common channel signals to determine observed time differences between a local base station and at least two additional base stations. It also uses the common channel signals to identify these base stations and to match the identifications to geographical locations. It further uses a geolocation algorithm to determine the location of the device relative to the base stations, and uses the geographic location data to determine the current geographic location of the device.

Abstract: An autonomous stratospheric airship comprising a hull which contains an equipment bay, forward and aft ballonets, forward and aft air management sub-systems, a propulsion system, and a control system is described. The airship also comprises a regenerative solar energy power and storage sub-system which allows powered daytime and nighttime operations. Further, the control system of the airship enables autonomous operation between selected waypoints or along a specified line of sight. The solar arrays utilized by the airship are internally mounted and gimballed so as to provide maximum collection efficiency and not impede the aerodynamic profile of the airship. A greatly simplified and slightly less controllable version of the airship, which makes use of alternative solar array control and ballast management systems, while carrying the equipment bay on the exterior of the hull, is also disclosed.

Abstract: An autonomous stratospheric airship comprising a hull which contains an equipment bay, forward and aft ballonets, forward and aft air management sub-systems, a propulsion system, and a control system is described. The airship also comprises a regenerative solar energy power and storage sub-system which allows powered daytime and nighttime operations. Further, the control system of the airship enables autonomous operation between selected waypoints or along a specified line of sight. The solar arrays utilized by the airship are internally mounted within the bull and gimballed so as to provide maximum collection efficiency and not impede the aerodynamic profile of the airship. A greatly simplified and slightly less controllable version of the airship, which makes use of alternative solar array control and ballast management systems, while carrying the equipment bay on the exterior of the hull, is also disclosed.

Abstract: An autonomous stratospheric airship comprising a hull which contains an equipment bay, forward and aft ballonets, forward and aft air management sub-systems, a propulsion system, and a control system is described. The airship also comprises a regenerative solar energy power and storage sub-system which allows powered daytime and nighttime operations. Further, the control system of the airship enables autonomous operation between selected waypoints or along a specified line of sight. The solar arrays utilized by the airship are internally mounted and gimballed so as to provide maximum collection efficiency and not impede the aerodynamic profile of the airship. A greatly simplified and slightly less controllable version of the airship, which makes use of alternative solar array control and ballast management systems, while carrying the equipment bay on the exterior of the hull, is also disclosed.

Abstract: A micropower DC voltage indicator is provided that is a two terminal device with a very high input impedance. An oscillator circuit is provided by a series of inverters, such as metal-oxide semiconductors (MOS) with the power inputs connected in parallel. A suitable RC circuit connects the output of one MOS inverter to the input of another MOS inverter, otherwise the output of each MOS inverter connects directly to the input of the next MOS inverter. Across one of the MOS inverters is connected a liquid crystal display which indicates if a DC voltage within a specific range is applied to the two terminals of the DC voltage indicator. The two terminal inputs to the oscillator circuit have a very high impedance and operate over a fairly broad DC voltage range.