Position and direction finding instrument
First Claim
1. A position and direction finding instrument comprising:
- a single, direction-finding, multimode antenna having at least four arms for receiving RF signals from a satellite;
a feed circuit connected to said direction-finding antenna for receiving signals from said antenna and for generating mode one and mode two signals; and
a global positioning system (GPS) receiver having stored satellite ephemeris data for determining the latitude and longitude of the GPS receiver and comprising electronic processing means connected to said feed circuit for determining a phase difference between the mode one and mode two signals, and for determining a forward direction of the instrument from the phase difference between the mode one and mode two signals, the stored satellite ephemeris data, and the latitude and longitude of the GPS receiver.
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Accused Products
Abstract
A position and direction finding instrument including a single, direction-finding, multimode antenna having at least four (4) arms for receiving RF signals from one or more satellites, a feed circuit connected to the direction-finding antenna for receiving signals from the antenna and for generating mode one and mode two signals, and a global positioning system (GPS) receiver having stored satellite ephemeris data for determining the latitude and longitude (position) of the GPS receiver and comprising electronic processing means connected to the feed circuit for determining a ratio of the magnitudes of the mode one and mode two signals relative to each other to determine a phase difference between the mode one and mode two signals, the electronic processing means determining a forward direction of the instrument from the phase difference between the mode one and mode two signals, the stored satellite ephemeris data, and the latitude and longitude of the GPS receiver.
39 Citations
9 Claims
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1. A position and direction finding instrument comprising:
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a single, direction-finding, multimode antenna having at least four arms for receiving RF signals from a satellite; a feed circuit connected to said direction-finding antenna for receiving signals from said antenna and for generating mode one and mode two signals; and a global positioning system (GPS) receiver having stored satellite ephemeris data for determining the latitude and longitude of the GPS receiver and comprising electronic processing means connected to said feed circuit for determining a phase difference between the mode one and mode two signals, and for determining a forward direction of the instrument from the phase difference between the mode one and mode two signals, the stored satellite ephemeris data, and the latitude and longitude of the GPS receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of determining forward direction with a GPS receiver and GPS satellites using the receiver position and the satellites ephemeris data comprising the steps of:
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receiving signals from at least one GPS satellite with an antenna; applying the received signals to a feed network to generate mode one and mode two signals; determining the phase shift between the mode one and mode two signals; and using the phase shift between the mode one and mode two signals, the satellite ephemeris data, and the position of the GPS receiver to determine forward direction. - View Dependent Claims (9)
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Specification