Abstract: A generalized high performance navigation system is provided using low earth orbit (LEO) satellites. In one embodiment, a method of performing navigation includes receiving a LEO signal from a LEO satellite. The method also includes decoding a navigation signal from the LEO signal. The method further includes receiving first and second ranging signals from first and second ranging sources, respectively. In addition, the method includes determining calibration information associated with the first and second ranging sources. The method also includes calculating a position using the navigation signal, the first and second ranging signals, and the calibration information.

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: A method for estimating a precise position of a user device from signals from a low earth orbit (LEO) satellite includes receiving at least one carrier signal at a user device, each carrier signal being transmitted a distinct LEO satellite. The user device processes the carrier signals to obtain a first carrier phase information. The user device recalls an inertial position fix derived at an inertial reference unit. The user device derives a position of the user device based on the inertial position fix and the first carrier phase information.

Abstract: This invention describes a means for acquiring GPS P/Y code under jamming conditions. It improves jam resistance by augmenting a component of the GPS signal with one from a different satellite system, such as a low earth orbiting (LEO) satellite. The preferred embodiment of this invention employs the Iridium LEO satellite constellation broadcasting in a 10 MHz wide band about 1,621 MHz. A low-cost, integrated Iridium receiver coupled to the GPS receiver employs a single antenna that is capable of receiving both the GPS and Iridium signals together.