Positioning system utilizing GPS satellites
First Claim
1. A positioning system utilizing GPS satellites comprisingreceiving means for receiving information from a plurality of GPS satellites which transmit their respective orbital information and timing information;
- deviation calculation means for calculating a difference Δ
f between a signal frequency transmitted by one of the GPS satellites and a signal frequency received by the receiving means;
variation calculation means for obtaining a rate of change Δ
Δ
f in the difference Δ
f;
and positioning calculation means for determining the position of the receiving means on the basis of information received by the receiving means from a plurality of GPS satellites for which the rate of change Δ
Δ
f remains within a preselected range.
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Accused Products
Abstract
A positioning system is disclosed in which a rate of change ΔΔf in a Doppler shift Δf of the radio wave transmitted from a GPS satellite is detected in order to determine whether or not an extraordinary radio wave as caused by a multi-path or the like is being received, and a GPS satellite from which an extraordinary radio wave is received is excluded from a group of GPS satellites which are utilized in a positioning calculation. A difference Δf between a signal frequency f0 transmitted from a GPS satellite and a signal frequency fR receiver is calculated, and a rate of change ΔΔf in the difference Δf is also calculated. The position of a receiver is calculated on the basis of information transmitted from a plurality of GPS satellites for which the rate of change ΔΔf is equal to or less than a first threshold value, or ΔΔf≦30 Hz/s, and the azimuth of a traveling direction of the receiver is calculated on the basis of information transmitted from a plurality of GPS satellites for which the rate of change ΔΔf is equal to or less than a second smaller threshold value or ΔΔf≦15 Hz/s.
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Citations
8 Claims
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1. A positioning system utilizing GPS satellites comprising
receiving means for receiving information from a plurality of GPS satellites which transmit their respective orbital information and timing information; -
deviation calculation means for calculating a difference Δ
f between a signal frequency transmitted by one of the GPS satellites and a signal frequency received by the receiving means;variation calculation means for obtaining a rate of change Δ
Δ
f in the difference Δ
f;and positioning calculation means for determining the position of the receiving means on the basis of information received by the receiving means from a plurality of GPS satellites for which the rate of change Δ
Δ
f remains within a preselected range. - View Dependent Claims (2, 3, 4)
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5. A positioning system utilizing GPS satellites comprising
receiving means for receiving information from a plurality of GPS satellites which transmit their orbital information and timing information; -
an altitude sensor for detecting the altitude of the receiving means; deviation calculation means for calculating a difference Δ
f between a signal frequency transmitted by one of the GPS satellites and a signal frequency by the receiving means;variation calculation means for determining a rate of change Δ
Δ
f in the difference Δ
f;and positioning calculation means for determining the position of the receiving means on the basis of information received by the receiving means from the GPS satellites when the number of GPS satellites for which the rate of change Δ
Δ
f remains within a preselected range is equal to four or greater, and for determining on the basis of information received by the receiving means from the GPS satellites and an altitude detected by the altitude sensor when the number of GPS satellites for the rate of change Δ
Δ
f remains within the preselected range is three. - View Dependent Claims (6, 7, 8)
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Specification