US 2002/0177952 A1Published application

Gps method and apparatus, navigation system, program storage device and computer data signal embodied in carrier wave

AssigneePioneer Corporation

InventorHajime Takemura

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Abstract

A GPS apparatus measures each pseudo-range ri from respective one of received radio waves from n GPS satellites (200i) captured by a GPS receiver (18) and approximately calculates a clock error t and coordinates (x, y, z) of the GPS receiver as a solution of n simultaneous equations by performing a convergence calculation with respect to n functions having such variables as the clock error t and the coordinates (x, y, z) of the GPS receiver. If a generation of a multi-path is detected, it approximately calculates the clock error t and the coordinates as a solution of n+1 simultaneous equations by performing a convergence calculation with respect to total n+1 functions obtained by adding one α fn+1 to the n functions, where αfn+1 is obtained by applying a weighting α to one function fn+1 having such variables as the clock error and the coordinates.

Claims15

Dependent claims

A GPS method comprising:

a measurement process of measuring each pseudo-range ri (i=1, 2, . . . , n) from respective one of received radio waves from n GPS satellites (n is a natural number equal to or greater than 3) captured by a GPS receiver mounted on a movable body;
a detection process of detecting a generation of a multi-path of the respective one of the received radio waves;
a first calculation process of approximately calculating a clock error t and coordinates (x, y, z) of the GPS receiver as a solution of n simultaneous equations by performing a convergence calculation with respect to n functions fi (x, y, z, t) having such variables as the clock error t and the coordinates (x, y, z), each of the n functions fi (x, y, z, t) representing the pseudo-range ri;
a second calculation process of approximately calculating the clock error t and the coordinates (x, y, z) as a solution of n+1 simultaneous equations by performing a convergence calculation with respect to total n+1 functions obtained by adding one αfn+1 (x, y, z, t) to the n functions fi (x, y, z, t), where the one αfn+1 (x, y, z, t) is obtained by applying a weighting α (α is a real number which is equal to or greater than 1) to one function fn+1 (x, y, z, t) having such variables as the clock error t and the coordinates (x, y, z), the one function fn+1 (x, y, z, t) representing a pseudo-range rn+1 obtained when the center of the earth is regarded as one GPS satellite;
an output process of outputting the coordinates (x, y, z) calculated in said first or second calculation process as current position data, which indicate a current position of the movable body;
and
a selection process of selecting said second calculation process when the generation of the multi-path is detected by said detection process.

4 more elements

A GPS apparatus comprising:

a measurement device for measuring each pseudo-range ri (i=1, 2, . . . , n) from respective one of received radio waves from n GPS satellites (n is a natural number equal to or greater than 3) captured by a GPS receiver mounted on a movable body;
a detection device for detecting a generation of a multi-path in the respective one of the received radio waves;
a first calculation device for approximately calculating a clock error t and coordinates (x, y, z) of the GPS receiver as a solution of n simultaneous equations by performing a convergence calculation with respect to n functions fi (x, y, z, t) having such variables as the clock error t and the coordinates (x, y, z), each of the n functions fi (x, y, z, t) representing the pseudo-range ri;
a second calculation device for approximately calculating the clock error t and the coordinates (x, y, z) as a solution of n+1 simultaneous equations by performing a convergence calculation with respect to total n+1 functions obtained by adding one αfn+1 (x, y, z, t) to the n functions fi (x, y, z, t), where the one αfn+1 (x, y, z, t) is obtained by applying a weighting α (α is a real number which is equal to or greater than 1) to one function fn+1 (x, y, z, t) having such variables as the clock error t and the coordinates (x, y, z), the one function fn+1 (x, y, z, t) representing a pseudo-range rn+1 obtained when the center of the earth is regarded as one GPS satellite;
an output device for outputting the coordinates (x, y, z) calculated in said first or second calculation device as current position data, which indicate a current position of the movable body;
and
a selection device for selecting said second calculation device when the generation of the multi-path is detected by said detection device.

4 more elements

A navigation system comprising:

(i) a GPS apparatus comprising:
a measurement device for measuring each pseudo-range ri (i=1, 2, . . . , n) from respective one of received radio waves from n GPS satellites (n is a natural number equal to or greater than 3) captured by a GPS receiver mounted on a movable body;
a detection device for detecting a generation of a multi-path in the respective one of the received radio waves;
a first calculation device for approximately calculating a clock error t and coordinates (x, y, z) of the GPS receiver as a solution of n simultaneous equations by performing a convergence calculation with respect to n functions fi (x, y, z, t) having such variables as the clock error t and the coordinates (x, y, z), each of the n functions fi (x, y, z, t) representing the pseudo-range ri;
a second calculation device for approximately calculating the clock error t and the coordinates (x, y, z) as a solution of n+1 simultaneous equations by performing a convergence calculation with respect to total n+1 functions obtained by adding one αfn+1 (x, y, z, t) to the n functions fi (x, y, z, t), where the one αfn+1 (x, y, z, t) is obtained by applying a weighting α (α is a real number which is equal to or greater than 1) to one function fn+1 (x, y, z, t) having such variables as the clock error t and the coordinates (x, y, z), the one function fn+1 (x, y, z, t) representing a pseudo-range rn+1 obtained when the center of the earth is regarded as one GPS satellite;
an output device for outputting the coordinates (x, y, z) calculated in said first or second calculation device as current position data, which indicate a current position of the movable body;
and
a selection device for selecting said second calculation device when the generation of the multi-path is detected by said detection device,
(ii) the GPS receiver;
and
(iii) a display device for displaying on map data the current position data outputted from said output device in a predetermined format.

8 more elements

A program storage device readable by a computer, tangibly embodying a program of instructions executable by the computer to perform method processes of outputting current position data, which indicate a current position of a movable body,

said method processes comprising:
a measurement process of measuring each pseudo-range ri (i=1, 2, . . . , n) from respective one of received radio waves from n GPS satellites (n is a natural number equal to or greater than 3) captured by a GPS receiver mounted on a movable body;
a detection process of detecting a generation of a multi-path of the respective one of the received radio waves;
a first calculation process of approximately calculating a clock error t and coordinates (x, y, z) of the GPS receiver as a solution of n simultaneous equations by performing a convergence calculation with respect to n functions fi (x, y, z, t) having such variables as the clock error t and the coordinates (x, y, z), each of the n functions fi (x, y, z, t) representing the pseudo-range ri;
a second calculation process of approximately calculating the clock error t and the coordinates (x, y, z) as a solution of n+1 simultaneous equations by performing a convergence calculation with respect to total n+1 functions obtained by adding one αfn+1 (x, y, z, t) to the n functions fi (x, y, z, t), where the one αfn+1 (x, y, z, t) is obtained by applying a weighting α (α is a real number which is equal to or greater than 1) to one function fn+1 (x, y, z, t) having such variables as the clock error t and the coordinates (x, y, z), the one function fn+1 (x, y, z, t) representing a pseudo-range rn+1 obtained when the center of the earth is regarded as one GPS satellite;
an output process of outputting the coordinates (x, y, z) calculated in said first or second calculation process as current position data, which indicate a current position of the movable body;
and
a selection process of selecting said second calculation process when the generation of the multi-path is detected by said detection process.

5 more elements

A computer data signal embodied in a carrier wave and representing a series of instructions which cause a computer to perform method processes of outputting current position data, which indicate a current position of a movable body,

said method processes comprising:
a measurement process of measuring each pseudo-range ri (i=1, 2, . . . , n) from respective one of received radio waves from n GPS satellites (n is a natural number equal to or greater than 3) captured by a GPS receiver mounted on a movable body;
a detection process of detecting a generation of a multi-path of the respective one of the received radio waves;
a first calculation process of approximately calculating a clock error t and coordinates (x, y, z) of the GPS receiver as a solution of n simultaneous equations by performing a convergence calculation with respect to n functions fi (x, y, z, t) having such variables as the clock error t and the coordinates (x, y, z), each of the n functions fi (x, y, z, t) representing the pseudo-range ri;
a second calculation process of approximately calculating the clock error t and the coordinates (x, y, z) as a solution of n+1 simultaneous equations by performing a convergence calculation with respect to total n+1 functions obtained by adding one αfn+1 (x, y, z, t) to the n functions fi (x, y, z, t), where the one αfn+1 (x, y, z, t) is obtained by applying a weighting α (α is a real number which is equal to or greater than 1) to one function fn+1 (x, y, z, t) having such variables as the clock error t and the coordinates (x, y, z), the one function fn+1 (x, y, z, t) representing a pseudo-range rn+1 obtained when the center of the earth is regarded as one GPS satellite;
an output process of outputting the coordinates (x, y, z) calculated in said first or second calculation process as current position data, which indicate a current position of the movable body;
and
a selection process of selecting said second calculation process when the generation of the multi-path is detected by said detection process.

5 more elements

Dependencies are inferred from the claim text.