Method and apparatus for detecting and measuring thickness of ice on aircraft
First Claim
1. A method for measuring a thickness of ice on an aircraft member, comprising:
- transmitting ultrasonic signals through said ice at predetermined applied voltages and frequencies;
measuring current and phase angle relative to voltage associated with each of said frequencies;
calculating impedance of a transducer from said applied voltage and measured current and phase angle relative to voltage at each of said predetermined frequencies;
determining frequencies where said impedance is a peak; and
determining thickness of said ice accumulated on said aircraft member based upon said peak impedance frequency values.
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Accused Products
Abstract
A method and apparatus for measuring the thickness of ice on an aircraft member is disclosed. In the preferred embodiment, the apparatus is mounted beneath an aircraft member surface. The apparatus includes transducers for transmitting ultrasonic signals through the aircraft member and ice at predetermined applied voltages and frequencies. The apparatus measures the current and phase angle relative to voltage associated with each transducer and frequency. The apparatus calculates the impedance of the transducer transmitting through aircraft member and any ice accumulation from the applied voltage and measured current and phase angle relative to voltage at each of the predetermined frequencies. The apparatus then computes the ice thickness by determining the frequencies where the impedance is a peak. The invention also broadly comprises an apparatus and a method for the detection of ice on an aircraft member.
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Citations
33 Claims
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1. A method for measuring a thickness of ice on an aircraft member, comprising:
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transmitting ultrasonic signals through said ice at predetermined applied voltages and frequencies;
measuring current and phase angle relative to voltage associated with each of said frequencies;
calculating impedance of a transducer from said applied voltage and measured current and phase angle relative to voltage at each of said predetermined frequencies;
determining frequencies where said impedance is a peak; and
determining thickness of said ice accumulated on said aircraft member based upon said peak impedance frequency values. - View Dependent Claims (2, 3, 4)
comparing thickness of member and ice to known thickness of said aircraft member with no ice accumulated thereon.
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3. The method recited in claim 1 further comprising:
sending data to a device that can display it to aircraft personnel.
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4. The method recited in claim 1 further comprising:
sending a signal to an alarm if said ice thickness measurement exceeds a preset limit.
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5. An apparatus for measuring a thickness of ice on an aircraft member, comprising:
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means for transmitting ultrasonic signals through said ice at predetermined applied voltages and frequencies;
means for measuring current and phase angle relative to voltage associated with each of said frequencies;
means for calculating impedance of a transducer from said applied voltage and measured current and phase angle relative to voltage at each of said predetermined frequencies;
means for determining frequencies where said impedance is a peak; and
means for determining thickness of said ice accumulated on said aircraft member based upon said peak impedance frequency values. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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13. An apparatus for measuring a thickness of ice on an aircraft member, comprising:
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an ultrasonic transducer mounted proximate to surface of said aircraft member, said transducer transmitting ultrasonic signals through said ice at predetermined applied voltages and frequencies; and
a microprocessor, said microprocessor measuring current and phase angle relative to voltage associated with each of said frequencies, calculating impedance of said transducer from said applied voltage and measured current and phase angle relative to voltage at each of said predetermined frequencies, determining frequencies where said impedance is a peak, and determining thickness of said ice accumulated on said aircraft member based upon said peak impedance frequency values. - View Dependent Claims (14, 15, 16)
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17. A method for measuring a thickness of ice on an aircraft member, comprising:
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calculating an impedance of a transducer, wherein said impedance calculation comprises calculating said impedance of said transducer from a commanded voltage of a transmitted signal and a measured current and phase angle relative to voltage; and
determining thickness of said ice accumulated on said aircraft member based upon said impedance. - View Dependent Claims (18, 19, 20, 21, 22, 23)
transmitting said signal through said ice.
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19. The method recited in claim 17 wherein said signal is an ultrasonic signal.
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20. The method recited in claim 17 wherein said impedance is calculated at a plurality of frequencies.
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21. The method recited in claim 20 wherein said plurality of frequencies comprises a band from a low frequency to a high frequency.
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22. The method recited in claim 21 wherein said low frequency is approximately equal to an average speed of sound through said aircraft member and said ice divided by four times a maximum thickness of said aircraft member and ice layer desired to be measured.
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23. The method recited in claim 21 wherein said high frequency is approximately equal to an average speed of sound through said aircraft member and said ice divided by four times a minimum thickness of said aircraft member and ice layer desired to be measured.
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24. An apparatus for measuring said thickness of ice on an aircraft member, comprising:
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means for calculating impedance of a transducer from a commanded voltage of a transmitted signal and a measured current and phase angle relative to voltage; and
means for determining thickness of said ice accumulated on said aircraft member based upon said impedance. - View Dependent Claims (25, 26, 27, 28, 29, 30)
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31. A method for detecting existence of ice on an aircraft member, comprising:
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transmitting ultrasonic signals at predetermined applied voltages and frequencies;
measuring current and phase angle relative to voltage associated with each of said frequencies;
calculating impedance of a transducer from said applied voltage and measured current and phase angle relative to voltage at each of said predetermined frequencies;
determining frequencies where said impedance is a peak; and
determining existence of said ice accumulated on said aircraft member based upon said peak impedance frequencies.
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32. An apparatus for detecting existence of ice on an aircraft member, comprising:
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an ultrasonic transducer mounted proximate to surface of said aircraft member, said transducer transmitting ultrasonic signals at predetermined applied voltages and frequencies; and
a microprocessor, said microprocessor measuring current and phase angle relative to voltage associated with each of said frequencies, calculating impedance of said transducer from said applied voltage and measured current and phase angle relative to voltage at each of said predetermined frequencies, determining frequencies where said impedance is a peak, and determining existence of said ice accumulated on said aircraft member based upon said peak impedance frequencies. - View Dependent Claims (33)
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Specification