Raytheon Company

Andrew M Hautzik

Ian S Robinson

Brandon Crow

Jon E Maenpa

Patrick M Sain

Richard Gerald Keegan

A global positioning system (GPS) receiver and system for determining a geographical location associated with the GPS receiver using less than four GPS signals. The system can comprise a constraint module configured to receive one or more constraints that describe at least one characteristic of a GPS receiver when a number of GPS satellites within a line of sight to the GPS receiver is below a defined value. The system can further comprise a pseudo range calculation module configured to calculate a plurality of pseudo ranges between the GPS receiver and the number GPS satellites, wherein the plurality of pseudo ranges are to various orbital positions of the GPS satellites over a period of time; and a geographical location module configured to determine the geographical location of the GPS receiver using the plurality of pseudo ranges and known constraints of motion associated with the GPS receiver.

Position and motion informed navigation system

Technology for determining a geographical location of a ground receiver is disclosed. A plurality of radio frequency (RF) signals from a plurality of RF signal carriers may be received at the ground receiver. The plurality of RF signal carriers may include satellites operated by a foreign entity or non-global positioning system (non-GPS) satellites. The ground receiver may measure a Doppler shift associated with each of the plurality of RF signals. The geographical location of the ground receiver may be determined in X, Y and Z coordinates based in part on the Doppler shift associated with each of the plurality of RF signals.

Determination of a ground receiver position

Global Navigation Satellite System (GNSS) pseudorange measurements must be compensated for receiver hardware and directionally dependent antenna errors to obtain desired accuracies for high precision GNSS positioning applications. The problem of pseudorange measurement errors resulting from directionally dependent group delays is not an issue in Fixed Reception Pattern Antenna (FRPA) GNSS sensors. However, for the complex case of a GNSS receiver employing a controlled reception pattern antenna (CRPA) and dynamic beam steering, the multiplicity of combinations of antenna element outputs makes compensation of directionally dependent antenna induced errors more difficult, as the simple subtraction that might be used for FRPA compensation does not work with a CRPA. Example embodiments provide for frequency domain correction of GNSS pseudorange measurements in CRPA receivers. The correction takes place in the signal processing of the satellite signals, after they have been converted to the frequency domain, but before they are formed into beams for the respective satellites.

System and method for frequency domain correction of global navigation satellite system pseudorance measurements in receivers having controlled reception pattern antennas

This invention discloses a method for enhancing a Global Navigation Satellite System (GNSS), such as Global Positioning System (GPS), location calculation by supplying carrier phase corrections within a GNSS receiver used with a multiple element Controlled Reception Pattern Antenna (CRPA) receiver. GNSS carrier phase measurements should be compensated for receiver hardware and directionally dependent antenna errors to obtain desired accuracies for high precision GNSS positioning applications. One technique successfully employed in Fixed Reception Pattern Antenna (FRPA) GPS sensors applies a simple directionally dependent set of correction factors to the measurement outputs. For the complex case of a GNSS receiver employing a CRPA and dynamic beam steering, however, the multiplicity of combinations of antenna element outputs makes the FRPA compensation technique impractical. Compensation of carrier phase measurements is a problem not addressed in previous GPS CRPA beam steering sensors.

System and method for correcting global navigation satellite system carrier phase measurements in receivers having controlled reception pattern antennas

Global Navigation Satellite System (GNSS) pseudorange measurements are compensated for receiver hardware and directionally dependent antenna errors to obtain desired accuracies for high precision GNSS positioning applications using a multiple element controlled reception pattern antenna (CRPA). Pseudorange errors are calibrated and stored in a sky map by azimuth, elevation, radio frequency (RF) channel, and frequency. Corrections are applied in real time to each pseudorange measurement by applying a combination of the stored errors. The coefficients of the errors in the combination are computed as a function of steering vectors and CRPA filter weights. This implements a generalized pseudorange correction able to compensate a GNSS CRPA sensor for channel dependent errors such as group delay for both the case of uniform weights for all frequencies and the more complex case of frequency-dependent weights.

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Rancho Palos Verdes, CA, United States of America

Andrew M Hautzik