Navigation system with accurate determination of angular velocity
First Claim
1. A navigation system which comprises:
- an angular velocity sensor for generating an output voltage corresponding to an angular velocity of a vehicle;
means for storing a reference voltage that corresponds to a value of zero for said angular velocity;
means for calculating a corrected angular velocity of said vehicle from both said reference voltage and said output voltage;
means for resetting said reference voltage;
a travel sensor for communicating a pulse whenever said vehicle runs a predetermined distance;
means for applying said pulse to said means for resetting;
said means for resetting employing, as an effective sampling interval, at least a part of an interval from an end of a predetermined first cancellation interval after said pulse has stopped until a start of a second cancellation interval prior to a resumption of said pulse;
said means for resetting including means for calculating an average value of said output voltage from a plurality of samples thereof taken periodically during said effective sampling interval;
said means for resetting including means for setting said reference voltage equal to said average value; and
said means for resetting employing, as said effective sampling interval, a one of;
(1) a whole interval from the termination of said first cancellation interval until the start of said second cancellation interval;
(2) a predetermined interval following said first cancellation interval; and
(3) a predetermined interval preceding said second cancellation interval;
means for locating said vehicle; and
means for applying said reference voltage to said means for locating.
9 Assignments
0 Petitions
Accused Products
Abstract
A navigation system having two sensors and two circuits. A travel sensor sends a pulse whenever a vehicle travels a predetermined distance. An angular velocity sensor outputs a voltage corresponding to an angular velocity of the vehicle. A correction circuit calculates the angular velocity from both a reference voltage that corresponds to an angular velocity of zero and an output voltage from the angular velocity sensor. A reference voltage resetting circuit monitors the pulse from the travel sensor; sets, as an effective sampling interval, at least a part of a interval from the end of a predetermined first cancellation interval after the pulse stops until the start of a second cancellation interval prior to a resumption of the pulse; calculates an average value of the output voltage of the angular velocity sensor, which has been periodically sampled during the effective sampling interval; and resets the reference voltage to the average value.
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Citations
16 Claims
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1. A navigation system which comprises:
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an angular velocity sensor for generating an output voltage corresponding to an angular velocity of a vehicle; means for storing a reference voltage that corresponds to a value of zero for said angular velocity; means for calculating a corrected angular velocity of said vehicle from both said reference voltage and said output voltage; means for resetting said reference voltage; a travel sensor for communicating a pulse whenever said vehicle runs a predetermined distance; means for applying said pulse to said means for resetting; said means for resetting employing, as an effective sampling interval, at least a part of an interval from an end of a predetermined first cancellation interval after said pulse has stopped until a start of a second cancellation interval prior to a resumption of said pulse; said means for resetting including means for calculating an average value of said output voltage from a plurality of samples thereof taken periodically during said effective sampling interval; said means for resetting including means for setting said reference voltage equal to said average value; and said means for resetting employing, as said effective sampling interval, a one of; (1) a whole interval from the termination of said first cancellation interval until the start of said second cancellation interval; (2) a predetermined interval following said first cancellation interval; and (3) a predetermined interval preceding said second cancellation interval; means for locating said vehicle; and means for applying said reference voltage to said means for locating. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A navigation system which comprises:
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an angular velocity sensor for generating an output voltage corresponding to an angular velocity of a vehicle; means for storing a reference voltage that corresponds to a value of zero for said angular velocity; a correction circuit for calculating a corrected angular velocity of said vehicle from both said reference voltage and said output voltage; a reference voltage resetting circuit for resetting said reference voltage; a travel sensor for communicating a pulse whenever said vehicle runs a predetermined distance; means for applying said pulse to said reference voltage resetting circuit; said reference voltage resetting circuit employing, as an effective sampling interval, at least a part of an interval from an end of a predetermined first cancellation interval after said pulse has stopped until a start of a second cancellation interval prior to a resumption of said pulse; said reference voltage resetting circuit calculating an average value of said output voltage from a plurality of samples thereof taken periodically during said effective sampling interval; said reference voltage resetting circuit including means for setting said reference voltage equal to said average value; said reference voltage resetting circuit employing, as said effective sampling interval, a one of; (1) a whole interval from the termination of said first cancellation interval until the start of said second cancellation interval; (2) a predetermined interval following said first cancellation interval; and (3) a predetermined interval preceding said second cancellation interval; means for locating said vehicle; and means for applying said reference voltage to said means for locating. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification