초록 ▼

A navigation system in which an uncoordinated beacon positioning system (UBS) is used in conjunction with an absolute positioning system (APS) is described herein. The UBS employs a multiplicity of transmitters, at known locations, each of which transmits a beacon signal having a phase that is at le

A navigation system in which an uncoordinated beacon positioning system (UBS) is used in conjunction with an absolute positioning system (APS) is described herein. The UBS employs a multiplicity of transmitters, at known locations, each of which transmits a beacon signal having a phase that is at least partially un-synchronized with the phases of the beacon signals of the other transmitters. Within a mobile unit, separate receivers are provided for receiving these beacon signals and for receiving APS signals. The absolute positioning system (APS) receiver is disposed to receive the APS signals, and to estimate an initial position of the mobile unit therefrom. The mobile unit processor is disposed to modify the estimated mobile unit position on the basis of the detected beacon signal phases. The mobile unit processor may also be programmed to determine the uncertainty of location information provided by the beacon signal receiver and by the APS receiver. This allows the current location of the mobile unit to be updated by selecting the location estimate having associated therewith the least amount of location uncertainty, or by weighting each estimate based on its uncertainty and combining the two weighted location estimates. In another implementation, the mobile unit includes an estimator operative to compute an estimate of mobile unit position on the basis of selected pseudorange measurements from the UBS and APS receivers. The estimator may include a Kalman filter configured to process residual pseudorange information provided by the UBS and APS receivers.

대표청구항 ▼

[ What is claimed is:] [1.] A positioning system for determining location of a mobile unit, said system making use of a multiplicity of transmitters, at known locations, each of which transmits a beacon signal having a phase that is at least partially un-synchronized with the phases of the beacon si

[ What is claimed is:] [1.] A positioning system for determining location of a mobile unit, said system making use of a multiplicity of transmitters, at known locations, each of which transmits a beacon signal having a phase that is at least partially un-synchronized with the phases of the beacon signals of the other transmitters, each of said beacon signals being of a predetermined repetition rate, said system comprising:an uncoordinated beacon positioning subsystem (UBS), said subsystem including a UBS receiver for receiving said beacon signals and for providing a UBS location of said mobile unit;an absolute positioning subsystem (APS) including an APS receiver for receiving APS signals and for providing an APS location of said mobile unit; anda processor for determining uncertainty of location information provided by said beacon signal receiver and said APS receiver, and updating a current location of said mobile unit based on said UBS and APS locations and said uncertainty of said location information;wherein the processor determines the uncertainty of location information for the APS receiver by measuring and evaluating at least one signal parameter associated with the APS signals, and determines the uncertainty of location information for the UBS receiver by measuring and evaluating at least one signal parameter associated with the received beacon signals.