No-outage GPS/commercial RF positioning system
First Claim
1. In a GPS system wherein a plurality of satellites transmit time and location data over radio frequency signals to enable a mobile GPS receiver station on the ground to determine its position and produce a GPS position signal, and a cellular telephone carried with said mobile GPS receiver, anda plurality of conventional ground based amplitude modulated (AM) transmitters for broadcasting AM signals, the improvement comprising:
- 1) each mobile GPS receiver station including phase detection means for simultaneously receiving a predetermined number of said AM signals, and measuring the changes in phase of each of said AM signals as said mobile GPS receiver travels, and deriving therefrom an AM position signal,2) a reference station for receiving said GPS and AM signals and providing correction signals and transmitting said correction signals by said cellular telephone to said mobile receiver station, and3) means for using said GPS position signal for resolving any ambiguities in said AM radio position signal and to accommodate the lack of synchronization in said AM transmitters.
3 Assignments
0 Petitions
Accused Products
Abstract
The present invention relates to a no outage GPS/AM position finding system wherein a GPS system having a plurality of satellites transmits time and location data over radio frequency signals to enable a mobile GPS receiver station on the ground to determine its position, and a cellular telephone is carried with the mobile GPS receiver, traveling in range of a plurality of conventional ground based amplitude modulated (AM) transmitters for transmitting AM signals. Each mobile GPS receiver station includes phase detection means for simultaneously receiving a predetermined number of the AM signals, and measuring the changes in phase of each of the AM signals as the mobile GPS receiver travels, and deriving therefrom an AM position signal. A reference station for receiving the GPS and AM signals provides correction signals via a cellular telephone network which receives and transmits the correction signals to the mobile GPS receiver station. The last accurate GPS position signal is used for resolving any ambiguities in the AM radio position signal and to accommodate the lack of synchronization in the AM transmitters. The reference station measures the frequency and wavelength variations in the AM signals and conveys same to the mobile GPS receiver station by the cellular telephone. The AM position signal is activated upon detecting outages or blockages in the GPS signals.
405 Citations
7 Claims
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1. In a GPS system wherein a plurality of satellites transmit time and location data over radio frequency signals to enable a mobile GPS receiver station on the ground to determine its position and produce a GPS position signal, and a cellular telephone carried with said mobile GPS receiver, and
a plurality of conventional ground based amplitude modulated (AM) transmitters for broadcasting AM signals, the improvement comprising: -
1) each mobile GPS receiver station including phase detection means for simultaneously receiving a predetermined number of said AM signals, and measuring the changes in phase of each of said AM signals as said mobile GPS receiver travels, and deriving therefrom an AM position signal, 2) a reference station for receiving said GPS and AM signals and providing correction signals and transmitting said correction signals by said cellular telephone to said mobile receiver station, and 3) means for using said GPS position signal for resolving any ambiguities in said AM radio position signal and to accommodate the lack of synchronization in said AM transmitters. - View Dependent Claims (2, 3, 4)
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5. A position location system operating in combination with a GPS system wherein a plurality of satellites transmit time and location data over radio frequency signals to enable a mobile GPS receiver station on the ground to determine its position, and a cellular telephone carried with said mobile GPS receiver, and wherein there are a plurality of conventional ground based commercial RF broadcast transmitters for transmitting commercial broadcast signals, characterized by:
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1) each mobile GPS receiver station including phase detection means for (1) simultaneously receiving a predetermined number of said commercial broadcast signals, and (2) measuring the changes in phase of each of said commercial broadcast signals as said mobile GPS receiver travels, and deriving therefrom a further position signal, and 2) means to detect GPS outage or black-out and providing said further position signal as an indication of position of said mobile GPS receiver station. - View Dependent Claims (6)
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7. A location finding navigation system for operating in an environment of GPS satellite signals and commercial radio wave (CR) broadcast signals and wherein from time-to-time said navigation system is in an obstructed GPS signal area, comprising:
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first receiver means for receiving a predetermined number of GPS satellite signals and producing a GPS location signal, second receiver means for receiving a predetermined number of said CR broadcast signals and producing a CR location signal, means connected to receive said GPS and CR location signal and selecting the most reliable of said location signals and presenting the most reliable location signal to a utilization device.
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Specification