GPS position tracking method with variable updating rate for power conservation
First Claim
1. A method for efficiently updating the position of mobile wireless user equipment (UE) to reduce the rate of energy consumption, comprising:
- establishing an update rate for determining position;
selecting a maximum error in position;
making a velocity prediction for said UE, including;
making a series of at least two position fixes at said update rate;
estimating the distance between at least two of said position fixes;
determining the time difference between the two position fixes;
responsive to said time difference and said estimated distance, calculating said velocity prediction of said UE;
adjusting said update rate responsive to said velocity prediction, including reducing said update rate to reduce power consumption without exceeding said maximum error in position; and
making a series of position fixes at said adjusted update rate, thereby efficiently utilizing energy stored in said UE.
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Accused Products
Abstract
A system and method in which the position update rate is adaptively modified, based on previous position measurements. By adjusting the update rate based on velocity predictions from two or more position fixes, a lower update rate may be used without exceeding the maximum error. Lowering the update rate reduces power consumption in the UE, providing longer battery operation. The updating method may comprise periodically repeating the velocity prediction and periodically adjusting the update rate responsive thereto. The update rate may be adjusted using additional information such as an acceleration prediction, a minimum update rate, or a preferred error. In some embodiments a model for user movement may be used to provide more accurate predictions, for example, stationary, walking, jogging, city driving, and freeway driving. The updating method may comprise receiving user input regarding the maximum position error.
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Citations
24 Claims
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1. A method for efficiently updating the position of mobile wireless user equipment (UE) to reduce the rate of energy consumption, comprising:
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establishing an update rate for determining position;
selecting a maximum error in position;
making a velocity prediction for said UE, including;
making a series of at least two position fixes at said update rate;
estimating the distance between at least two of said position fixes;
determining the time difference between the two position fixes;
responsive to said time difference and said estimated distance, calculating said velocity prediction of said UE;
adjusting said update rate responsive to said velocity prediction, including reducing said update rate to reduce power consumption without exceeding said maximum error in position; and
making a series of position fixes at said adjusted update rate, thereby efficiently utilizing energy stored in said UE. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for efficiently updating the position of mobile wireless user equipment (UE) to reduce energy consumption while still providing accurate position information over time, comprising:
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making a velocity prediction for said UE, including;
making a first position fix at a first time;
making a second position fix at a second time;
calculating the time delay between the first and second position fixes;
estimating the travel distance between said first and second position fixes;
responsive to said calculated time delay and said estimated travel distance, calculating an actual velocity and predicting said velocity of said UE over a next time period;
adjusting the time delay for the next position fix responsive to said velocity prediction; and
making a third position fix responsive to said time delay to update the position of said UE at a third time subsequent to said second time, thereby efficiently utilizing energy stored in said UE. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A system for efficiently updating the position of mobile wireless user equipment (UE) to reduce the rate of energy consumption, comprising:
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means for establishing an update rate for determining position;
means for selecting a maximum error in position;
means for making a velocity prediction for said UE, including;
means for making a series of at least two position fixes at said update rate;
means for estimating the distance between at least two of said position fixes;
means for determining the time difference between the two position fixes;
means, responsive to said time difference and said estimated distance, for calculating said velocity prediction of said UE;
means for adjusting said update rate responsive to said velocity prediction, including reducing said update rate to reduce power consumption without exceeding said maximum error in position; and
means for making a series of position fixes at said adjusted update rate, thereby efficiently utilizing energy stored in said UE. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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Specification