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US 2002/0177950 A1Published application
Satellite based on-board vehicle navigation system including predictive filtering and map-matching to reduce errors in a vehicular position
AssigneePRC Inc.
InventorF. Bryan Davies
Life of this patent
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Abstract
An accurate position of a mobile receiver is determined using a received positional signal having relatively low and high frequency noise components corrupting the positional accuracy of the positional signal. A low frequency error associated with a detected turn of the mobile receiver is derived and applied as a low frequency correction factor to positions of the receiver derived after the turn is detected. Resulting corrected positions are applied along with associated high frequency correction factors representative of the high frequency noise component to a predictive filter to derive predicted positions substantially free of the low and high frequency noise components.
Claims34
A method of rapidly associating a position of a mobile receiver (MR) with a navigable route accessible in a map database, the map database including information representing predetermined navigable routes, comprising:
- seeding a predictive filter with an initial value indicative of an erroneous current position value of the MR displaced a predetermined minimum distance from a known approximate position of the MR to establish an initial gain of the predictive filter;
- receiving a positional signal over m time periods and deriving position values of the MR over the m time periods using the received signal;
- deriving predicted position values of the MR over the m time periods by predictively filtering the position values with the predictive filter;
- and
- determining a probable position of the MR at an end of the m time periods using a current predicted position value, the probable position coinciding with a navigable route of where the MR is probably positioned at the end of the m time periods.
2 more elements
A method of accurately determining the position of a mobile receiver (MR) based upon a received positional signal having relatively low and high frequency noise components corrupting the positional accuracy of the received signal, comprising:
- (a) detecting a turn of the MR using the received positional signal and deriving a first positional offset associated with the turn and representative of the low frequency noise component;
- (b) deriving a position value of the MR using the received positional signal after detecting the turn, and correcting the position value with the first positional offset associated with the turn to derive a corrected position value;
- and
- (c) applying the corrected position value to a filter along with a second positional offset associated with the corrected position value and representative of the high frequency noise component to derive a filtered position value substantially free of the low and high frequency noise components.
1 more element
A method of accurately determining the position of a mobile receiver (MR) based upon a received positional signal having low and high frequency components corrupting the positional accuracy of the received signal, comprising:
- (a) receiving the positional signal over time intervals T1 through Tm, where T represents the duration of each time interval and the subscript represents the position of each time interval in the sequence of time intervals T1 through Tm;
- (b) deriving position values of the MR at time intervals T1 through Tm using the received positional signal;
- (c) predictively filtering the position values at time intervals T1 through Tm−1 with a predictive filter to derive predicted position values of the MR at time intervals T1 through Tm−1;
- (d) deriving a first positional error indicative of a low frequency noise component reducing the accuracy of the position values and predicted position values at time intervals T1 through Tm using predicted position values T1 through Tm−1;
- (e) correcting the position value at time interval Tm with the first positional error to derive a corrected position value at time interval Tm;
- and
- (f) predictively filtering the corrected position value at time interval Tm to derive a predicted position of the MR at time interval Tm, the predicted position at time interval Tm being substantially free of the low frequency noise component.
4 more elements
The method as recited in claim 28, further including the steps of
- receiving the positional signal and deriving a position value of the MR at a time interval Tm+1 using the positional signal;
- correcting the position value at time interval Tm+1 with the first positional error to derive a corrected position value at time Tm+1;
- deriving a second positional error indicative of a high frequency noise component reducing the accuracy of the position value at time interval Tm+1, the second positional error value being determined using the corrected position value at time Tm+1 and the predicted position value at Tm;
- applying the second positional error to the predictive filter at time interval Tm+1 as a positional variance error to drive a gain of the predictive filter;
- and
- predictively filtering the corrected position value at time interval Tm+1 with the predictive filter to derive a predicted position value of the MR at time interval Tm+1, the predicted position at time interval Tm+1 being substantially free of the low and high frequency noise components.
3 more elements
A method of accurately determining the position of a mobile receiver (MR) based upon a received positional signal having relatively low and high frequency components corrupting the positional accuracy of the received signal, comprising:
- receiving the positional signal and deriving position values of the MR using the positional signal;
- applying the position values to a predictive filter to derive predicted position values of the MR;
- detecting a turn of the MR using the predicted position values and deriving a first positional offset associated with the turn and representative of the low frequency noise component;
- correcting position values with the first positional offset to derive corrected position values after detecting the turn;
- deriving a second positional offset between each of the corrected position values and a navigable route coinciding with where the MR is probably located for each of the corrected position values, the second positional offset being representative of the high frequency noise;
- and
- applying each of the corrected position values along with the second positional offset associated with each of the corrected position values to the predictive filter to derive predicted position values substantially free of the low frequency and high frequency noise.
4 more elements
An article, comprising:
- at least one sequence of machine executable instructions;
- a medium bearing the executable instructions in machine readable form,
- wherein execution of the instructions by one or more processors causes the one or more processors to:
- seed a predictive filter with an initial value indicative of an erroneous current position value of a mobile receiver (MR) displaced a predetermined minimum distance from a known approximate position of the MR to establish an initial gain of the predictive filter;
- receive a positional signal over m time periods and derive position values of the MR over the m time periods using the received signal;
- derive predicted position values of the MR over the m time periods by predictively filtering the position values with the predictive filter;
- and
- determine a probable position of the MR at an end of the m time periods using a current predicted position value, the probable position coinciding with a navigable route of where the MR is probably positioned at the end of the m time periods.
5 more elements
An article, comprising:
- at least one sequence of machine executable instructions;
- a medium bearing the executable instructions in machine readable form,
- wherein execution of the instructions by one or more processors causes the one or more processors to:
- (a) detect a turn of a mobile receiver (MR) using a received positional signal having a positional accuracy corrupted by relatively low and high frequency noise components, and derive a first positional offset associated with the turn and representative of the low frequency noise component;
- (b) derive a position value of the MR using the received positional signal after detecting the turn, and correct the position value with the first positional offset associated with the turn to derive a corrected position value;
- and
- (c) apply the corrected position value to a filter along with a second positional offset associated with the corrected position value and representative of the high frequency noise component to derive a filtered position value substantially free of the low and high frequency noise components.
4 more elements
A computer architecture, comprising:
- seeding means for seeding a predictive filter with an initial value indicative of an erroneous current position value of a mobile receiver (MR) displaced a predetermined minimum distance from a known approximate position of the MR to establish an initial gain of the predictive filter;
- receiving means for receiving a positional signal over m time periods and for deriving position values of the MR over the m time periods using the received signal;
- deriving means for deriving predicted position values of the MR over the m time periods by predictively filtering the position values with the predictive filter;
- and
- determining means for determining a probable position of the MR at an end of the m time periods using a current predicted position value, the probable position coinciding with a navigable route of where the MR is probably positioned at the end of the m time periods.
2 more elements
A computer architecture, comprising:
- (a) detecting means for detecting a turn of a mobile receiver (MR) using a received positional signal having a positional accuracy corrupted by relatively low and high frequency noise components, and for deriving a first positional offset associated with the turn and representative of the low frequency noise component;
- (b) deriving means for deriving a position value of the MR using the received positional signal after detecting the turn, and correcting means for correcting the position value with the first positional offset associated with the turn to derive a corrected position value;
- and
- (c) applying means for applying the corrected position value to a filter along with a second positional offset associated with the corrected position value and representative of the high frequency noise component to derive a filtered position value substantially free of the low and high frequency noise components.
1 more element
A computer system, comprising:
- a processor;
- and
- a memory coupled to the processor, the memory having stored therein sequences of instructions, which, when executed by the processor, cause the processor to perform the steps of:
- seeding a predictive filter with an initial value indicative of an erroneous current position value of a mobile receiver (MR) displaced a predetermined minimum distance from a known approximate position of the MR to establish an initial gain of the predictive filter;
- receiving a positional signal over m time periods and deriving position values of the MR over the m time periods using the received signal;
- deriving predicted position values of the MR over the m time periods by predictively filtering the position values with the predictive filter;
- and
- determining a probable position of the MR at an end of the m time periods using a current predicted position value, the probable position coinciding with a navigable route of where the MR is probably positioned at the end of the m time periods.
5 more elements
A computer system, comprising:
- a processor;
- and
- a memory coupled to the processor, the memory having stored therein sequences of instructions, which, when executed by the processor, cause the processor to perform the steps of:
- (a) detecting a turn of a mobile receiver (MR) using a received positional signal having a positional accuracy corrupted by relatively low and high frequency noise components, and deriving a first positional offset associated with the turn and representative of the low frequency noise component;
- (b) deriving a position value of the MR using the received positional signal after detecting the turn, and correcting the position value with the first positional offset associated with the turn to derive a corrected position value;
- and
- (c) applying the corrected position value to a filter along with a second positional offset associated with the corrected position value and representative of the high frequency noise component to derive a filtered position value substantially free of the low and high frequency noise components.
4 more elements
Dependencies are inferred from the claim text.