Method and device for processing measurement signals from a movement sensor on board a motor vehicle
DCFirst Claim
1. A method of processing measurement signals from a movement sensor (2) on board a motor vehicle, the method comprising the steps of:
- in a preliminary phase;
measuring, with the vehicle stopped, a reference value (AcOFF) of a signal output by the movement sensor (2), and storing said measured reference value as an offset value;
by an acceleration value (Sa) determining a running threshold of the motor vehicle and fixing and storing the running threshold; and
storing a noise value (Bb), the noise value being characteristic of operation of the movement sensor (2) and representative of white noise of the movement sensor (2); and
then, throughout the life of the vehicle;
measuring the movement sensor signal output by executing sequences of a quantity n of successive measurements of the signal output, to produce a corresponding n successive measured values for each sequence,wherein, for each sequence, i) the stored offset value is subtracted from each of the n successive measured values of each sequence to produce n calculated values, ii) each of the n calculated values is compared with the stored running threshold, and iii) information representative of a stopped state of the vehicle is transmitted if, and only if, the n calculated values are all less than the stored running threshold, and the n calculated values are each equal to each other within a tolerance margin corresponding to the stored noise value.
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Abstract
The invention relates to a method of processing measurement signals from a movement senor on board a motor vehicle, according to which, initially, and in a preliminary phase, a reference value AcOff, called offset value, is stored, representative of the value of the signal output by the movement sensor, with the vehicle stopped, a so-called noise value Bb representative of the white noise of said sensor, and an acceleration value Sa determining a running threshold of the motor vehicle. Then, according to this method, and throughout the life of the vehicle, sequences of n successive measurements are taken of the value Ac(t) of the signal output by the movement sensor, and, for each of these sequences, the stored offset value AcOff is subtracted from each of the n measured value and each of the duly calculated values is compared with the stored running threshold, and information representative of a stopped state of the vehicle is transmitted if, and only if, the n calculated values are all less than the stored running threshold and roughly equal to each other with a tolerance margin corresponding to the stored noise value.
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Citations
18 Claims
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1. A method of processing measurement signals from a movement sensor (2) on board a motor vehicle, the method comprising the steps of:
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in a preliminary phase; measuring, with the vehicle stopped, a reference value (AcOFF) of a signal output by the movement sensor (2), and storing said measured reference value as an offset value; by an acceleration value (Sa) determining a running threshold of the motor vehicle and fixing and storing the running threshold; and storing a noise value (Bb), the noise value being characteristic of operation of the movement sensor (2) and representative of white noise of the movement sensor (2); and then, throughout the life of the vehicle; measuring the movement sensor signal output by executing sequences of a quantity n of successive measurements of the signal output, to produce a corresponding n successive measured values for each sequence, wherein, for each sequence, i) the stored offset value is subtracted from each of the n successive measured values of each sequence to produce n calculated values, ii) each of the n calculated values is compared with the stored running threshold, and iii) information representative of a stopped state of the vehicle is transmitted if, and only if, the n calculated values are all less than the stored running threshold, and the n calculated values are each equal to each other within a tolerance margin corresponding to the stored noise value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A device for processing measurement signals from a movement sensor (2) on board a motor vehicle, comprising:
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measurement means (3) of measuring values of the signals (AcB) output by the movement sensor (2); storage means (4) of storing i) a reference value (AcOFF), called an offset value, representative of the value of a reference signal output by the movement sensor (2) when the vehicle is stopped, ii) a noise value (Bb) characteristic of operation of the movement sensor and representative of white noise of the movement sensor, and iii) an acceleration value (Sa) determining a running threshold of the vehicle; and a computation unit (5), connected to the measurement means (3) and to the storage means (4), and programmed to, throughout the life of the vehicle, command sequences of n successive measurements of the value of the signal output by the movement sensor (2), and for each of these sequences, i) to subtract the stored offset value from each of the n measured values as calculated values and compare each of the calculated values with the stored running threshold, and ii) to command the transmission of information representative of a stopped state of the vehicle if, and only if, a) the n calculated values are all less than the stored running threshold, and b) the n calculated values are all equal to each other within a tolerance margin corresponding to the stored noise value.
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Specification