Method for detecting vehicle speed
First Claim
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1. A method for detecting vehicle speed, comprising the steps of:
- (1) detecting power supply noise frequency and converting to an engine speed through a vehicle power supply noise detection unit of a vehicle speed detection apparatus;
(2) detecting an acceleration value through an accelerometer and processing to get a second estimated vehicle speed;
(3) comparing the engine speed with a first estimated vehicle speed of GPS to establish a vehicle speed table after having incorporated gearshift modifications to derive a third estimated vehicle speed; and
(4) selecting a final vehicle speed based on satellite signal receiving conditions and the comparison result of the engine speed with the vehicle speed.
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Abstract
A method for detecting vehicle speed detects existing noise frequency of vehicle power supply and vehicle acceleration value, and compares and processes the detected data to estimate the final vehicle speed. The method includes the procedure of (1) detecting power supply noise frequency and converting to engine speed; (2) detecting acceleration value; (3) comparing the engine speed and the vehicle speed; and (4) selecting the final vehicle speed. By means of the procedure of the invention, the vehicle speed may be provided to the vehicle navigation apparatus to continuously perform navigation during the brief period when the GPS signals are lost.
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10 Claims
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1. A method for detecting vehicle speed, comprising the steps of:
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(1) detecting power supply noise frequency and converting to an engine speed through a vehicle power supply noise detection unit of a vehicle speed detection apparatus;
(2) detecting an acceleration value through an accelerometer and processing to get a second estimated vehicle speed;
(3) comparing the engine speed with a first estimated vehicle speed of GPS to establish a vehicle speed table after having incorporated gearshift modifications to derive a third estimated vehicle speed; and
(4) selecting a final vehicle speed based on satellite signal receiving conditions and the comparison result of the engine speed with the vehicle speed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification