Abstract: Systems and methods according to various embodiments provide for navigation in attenuated environments by integrating satellite signals with Internet hotspot signals. In one embodiment, a receiver unit adapted to perform geolocation comprises an antenna adapted to receive a precision time signal from a satellite and receive additional aiding information from a wireless network station, wherein the precision time signal comprises a periodic repeating code.

Abstract: Systems and methods according to one or more embodiments are provided for obtaining a precise absolute time using a satellite system. The precise absolute time may be used, for example, as an aid for positioning systems including navigation in attenuated or jammed environments. A method of obtaining precise absolute time transfer from a satellite according to an embodiment comprises: receiving a precision time signal from a satellite, wherein the precision time signal comprises a periodic repeating code; determining a timing phase of the code; receiving additional aiding information; and using the timing phase and the additional aiding information to determine a precise absolute time.

Abstract: A low earth orbit (LEO) satellite data uplink is provided. In one embodiment, a method of providing a data uplink to a LEO satellite includes determining position information using a LEO signal received from the LEO satellite, a first ranging signal received from a first ranging source, and a second ranging signal received from a second ranging source. The method also includes determining a timing advance parameter using a local clock reference and a LEO satellite clock reference. The method further includes preparing a data uplink signal comprising uplink data to be broadcast to the LEO satellite. In addition, the method includes synchronizing the data uplink signal with the LEO satellite using the timing advance parameter. The method also includes broadcasting the data uplink signal to the LEO satellite.

Abstract: Low earth orbit (LEO) satellites are used to provide navigation signals. In one embodiment, a method of providing a LEO signal from a LEO satellite includes providing a plurality of transmit channels over a plurality of transmit slots. The transmit channels comprise a set of communication channels and a set of navigation channels. The method also includes generating a first pseudo random noise (PRN) ranging overlay corresponding to a navigation signal. The method further includes applying the first PRN ranging overlay to a first set of the navigation channels. In addition, the method includes combining the communication channels and the navigation channels into a LEO signal. The method also includes broadcasting the LEO signal from the LEO satellite.

Abstract: Various approaches to localized jamming of navigation signals are provided. In one embodiment, a navigation signal comprises at least a portion of a low earth orbit (LEO) signal provided by a LEO satellite. A noise source is filtered to provide a plurality of filtered noise signals in a plurality of frequency bands. The navigation signal is spread over a plurality of channels of the LEO signal. The channels are distributed over the frequency bands and a plurality of time slots. A pseudo random noise (PRN) sequence is generated. The filtered noise signals are modulated using the PRN sequence to provide a plurality of modulated noise signals. The modulated noise signals are broadcast over an area of operations to provide a plurality of jamming bursts corresponding to the navigation signal. The jamming bursts are configured to substantially mask the navigation signal in the area of operations.

Abstract: Various approaches to localized jamming of navigation signals are provided. In one embodiment, a navigation signal comprises at least a portion of a low earth orbit (LEO) signal provided by a LEO satellite. A noise source is filtered to provide a plurality of filtered noise signals in a plurality of frequency bands. The navigation signal is spread over a plurality of channels of the LEO signal. The channels are distributed over the frequency bands and a plurality of time slots. A pseudo random noise (PRN) sequence is generated. The filtered noise signals are modulated using the PRN sequence to provide a plurality of modulated noise signals. The modulated noise signals are broadcast over an area of operations to provide a plurality of jamming bursts corresponding to the navigation signal. The jamming bursts are configured to substantially mask the navigation signal in the area of operations.

Abstract: A navigation system provides a significant level of protection against all forms of interference or jamming to GPS in a cost-effective way. The system employs a network of ground reference stations and Low Earth Orbiting (LEO) satellites in conjunction with GPS. A common-view ranging geometry to a GPS satellite is established that links a reference station and a user. A second common-view geometry to a LEO satellite between the same reference station and user pair is also established. The ground stations synthesize real-time aiding signals by making carrier phase measurements of GPS the LEO satellite signals. This aiding information is transmitted via the LEO satellites to the user receiver at high power to penetrate ambient jamming. The user receiver locks onto the carrier phase of the LEO satellite, demodulates the aiding information, then applies the carrier phase measurements and the aiding information to enable extended coherent measurements of the GPS signals.

Abstract: A navigation system provides a significant level of protection against all forms of interference or jamming to GPS in a cost-effective way. The system employs a network of ground reference stations and Low Earth Orbiting (LEO) satellites in conjunction with GPS. A common-view ranging geometry to a GPS satellite is established that links a reference station and a user. A second common-view geometry to a LEO satellite between the same reference station and user pair is also established. The ground stations synthesize real-time aiding signals by making carrier phase measurements of GPS the LEO satellite signals. This aiding information is transmitted via the LEO satellites to the user receiver at high power to penetrate ambient jamming. The user receiver locks onto the carrier phase of the LEO satellite, demodulates the aiding information, then applies the carrier phase measurements and the aiding information to enable extended coherent measurements of the GPS signals.