WO2006121583A1 - Improvement of environmental characteristic determination - Google Patents

Improvement of environmental characteristic determination Download PDF

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Publication number
WO2006121583A1
WO2006121583A1 PCT/US2006/014602 US2006014602W WO2006121583A1 WO 2006121583 A1 WO2006121583 A1 WO 2006121583A1 US 2006014602 W US2006014602 W US 2006014602W WO 2006121583 A1 WO2006121583 A1 WO 2006121583A1
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WO
WIPO (PCT)
Prior art keywords
values
concomitant
independent
sensors
processor
Prior art date
Application number
PCT/US2006/014602
Other languages
French (fr)
Inventor
Christopher I. Reynolds
Donald Heckathorn
Michael Perlmutter
Ian Humphrey
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Northrop Grumman Corporation
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Publication of WO2006121583A1 publication Critical patent/WO2006121583A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P21/00—Testing or calibrating of apparatus or devices covered by the preceding groups
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
    • G01C21/10—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration
    • G01C21/12—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning
    • G01C21/16—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation
    • G01C21/166—Mechanical, construction or arrangement details of inertial navigation systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values

Definitions

  • the invention relates generally to signal processing and more particularly to error reduction in gyroscopes and accelerometers.
  • Gyroscopes are capable of measuring inertial characteristics, such as angular rate and/or acceleration.
  • IMUs inertial measurement units
  • a single gyroscope is used for each range of motion that is to be measured.
  • IMUs employ a gyroscope for pitch, a gyroscope for roll, and a gyroscope for yaw.
  • additional gyro(s) may be used for redundancy so that on the event of a gyro failure the redundant gyros(s) data may be used.
  • Outputs from gyroscopes may be unstable due to error terms that vary over time.
  • error terms are caused by environmental changes to the gyroscope, such as temperature fluctuation, shock, and vibration.
  • the error terms may or may not be correlated with each other and may or may not vary between gyroscopes.
  • a specialized and more precise gyroscope may be used to reduce the error terms, but at a higher manufacturing cost. Thus, a need exists for reduced error terms in environmental characteristic measurements without higher manufacturing costs.
  • the invention in one implementation encompasses an apparatus.
  • the apparatus comprises: plurality of concomitant values indicative of an environmental characteristic; and a processor having a plurality of inputs for receiving the plurality of concomitant values and having an output that provides a determination of the environmental characteristic; wherein the processor determines the environmental characteristic based on a combination of the plurality of concomitant values.
  • Another implementation of the invention encompasses a method.
  • the method comprises: determining, via a plurality of independent electronic sensors, a plurality of independent, concomitant values indicative of an environmental characteristic; calculating, via a processor, an average of the plurality of independent, concomitant values of the environmental characteristic; and providing the average of the plurality of independent, concomitant values as a single value indicative of the environmental characteristic.
  • a further implementation of the invention encompasses an apparatus.
  • the apparatus comprises an inertial measurement unit that provides a pitch angular rate measurement, a roll angular rate measurement, and a yaw angular rate measurement.
  • the inertial measurement unit comprises: a pitch circuit that comprises a pitch processor and a plurality of independent pitch sensors; a roll circuit that comprises a roll processor and a plurality of independent roll sensors; and a yaw circuit that comprises a yaw processor and a plurality of independent yaw sensors.
  • the pitch processor receives a plurality of concomitant pitch values from the plurality of independent pitch sensors.
  • the pitch processor determines an average of the concomitant pitch values.
  • the roll processor receives a plurality of concomitant roll values from the plurality of independent roll sensors.
  • the roll processor determines an average of the concomitant roll values.
  • the yaw processor receives a plurality of concomitant yaw values from the plurality of independent yaw sensors.
  • the yaw processor determines an average of the concomitant yaw values.
  • the inertial measurement unit provides the average of the concomitant pitch values as the pitch angular rate measurement.
  • the inertial measurement unit provides the average of the concomitant roll values as the roll angular rate measurement.
  • the inertial measurement unit provides the average of the concomitant yaw values as the yaw angular rate measurement.
  • FIG. 1 is a representation of one implementation of an apparatus that comprises a circuit with a processor and a plurality of sensors.
  • FIG. 2 is a representation of another implementation of the apparatus of FIG. 1 that comprises a plurality of circuit boards.
  • FIG. 3 is a representation of an exemplary plot of short term drift for a single gyroscope.
  • FIG. 4 is a representation of exemplary plots of short term drift for the apparatus of FIG. 1 where the plurality of sensors comprises four gyroscopes.
  • FIG. 5 is a representation of an exemplary plot of short term drift for the apparatus of FIG. 1 where the plurality of sensors comprises sixteen gyroscopes.
  • FIG. 6 is a representation of an exemplary histogram of temperature coefficient for individual accelerometers.
  • FIG. 7 is a representation of an exemplary histogram of temperature coefficient for the apparatus of FIG. 1 where the plurality of sensors comprises four accelerometers.
  • FIG. 8 is a representation of an exemplary histogram of temperature coefficient for the apparatus of FIG. 1 where the plurality of sensors comprises sixteen accelerometers.
  • an apparatus 100 in one example comprises a circuit 101.
  • the circuit 101 in one example comprises a processor 102 and a plurality of n sensors, for example, sensors 104, 106, 108, and 110.
  • the processor 102 in one example comprises a signal processor.
  • the processor 102 receives signals from the sensors 104, 106, 108, and 110.
  • the processor 102 in one example comprises a digital signal processor.
  • the processor 102 comprises an analog signal processor.
  • the processor 102 comprises an analog/digital converter 112 ("A/D D/A") for conversion of signals between an analog format and a digital format.
  • the processor 102 makes a determination of an environmental characteristic based on an average of a plurality of concomitant values that correspond to the environmental characteristic.
  • the processor 102 in one example comprises an instance of a recordable data storage medium 114 ("RDSM"), as described herein.
  • the sensors 104, 106, 108, and 110 comprise electronic sensors.
  • the sensors 104, 106, 108, and 110 serve to obtain a plurality of concomitant values that correspond to the environmental characteristic for the processor 102.
  • the sensors 104, 106, 108, and 110 measure the environmental characteristic.
  • the environmental characteristic in one example comprises an inertial characteristic, for example, an angular rate or angular acceleration.
  • the environmental characteristics comprise temperature, pressure, strain, electrical field strength, and/or magnetic field strength.
  • the sensors 104, 106, 108, and 110 in one example comprise one or more gyroscopes for measuring the angular rate and/or one or more accelerometers for measuring the angular acceleration.
  • the sensors 104, 106, 108, and 110 comprise Micro-Electro-Mechanical Systems (MEMS) gyroscopes and/or accelerometers.
  • MEMS Micro-Electro-Mechanical Systems
  • the gyroscopes and/or accelerometer in one example are single- and/or multi-axis.
  • the gyroscopes and/or accelerometers are oriented along a same axis.
  • the gyroscopes and/or accelerometers are oriented along different axes.
  • the angular rates are mathematically combined through employment of relative scaling to obtain a measurement for a desired axis, as will be appreciated by those skilled in the art.
  • the sensors 104, 106, 108, and 110 in one example comprise independent sensors.
  • each of the sensors 104, 106, 108, and 110 provides a value that corresponds to a measurement of the environmental characteristic.
  • the sensors 104, 106, 108, and 110 in one example provide the values at and/or from a pre-determined time.
  • the sensors 104, 106, 108, and 110 are synchronized with a pre-determined clock signal.
  • the sensors 104, 106, 108, and 110 operate in real-time.
  • the sensors 104, 106, 108, and 110 provide a continuous output of the value.
  • the sensors 104, 106, 108, and 110 in one example provide the values substantially in parallel, as will be appreciated by those skilled in the art.
  • an inertial measurement unit 202 in one example comprises a plurality of circuits 101 and a support circuit 203.
  • each circuit 101 corresponds to a dimension of travel.
  • the circuits 101 comprise a pitch circuit 204, a roll circuit 206, and a yaw circuit 208.
  • the inertial measurement unit 202 employs the pitch circuit 204, the roll circuit 206, and the yaw circuit 208 to provide a pitch angular rate measurement, a roll angular rate measurement, and a yaw angular rate measurement, respectively.
  • the pitch circuit 204, the roll circuit 206, and the yaw circuit 208 are functionally and electrically identical.
  • the pitch circuit 204, the roll circuit 206, and the yaw circuit 208 are oriented orthogonally to each other to provide the pitch angular rate measurement, the roll angular rate measurement, and the yaw angular rate measurement, as will be appreciated by those skilled in the art.
  • the support circuit 203 is electrically coupled with the pitch circuit 204, the roll circuit 206, and the yaw circuit 208.
  • the support circuit 203 in one example comprises one or more communication and/or power interfaces and support logic for the pitch circuit 204, the roll circuit 206, and the yaw circuit 208.
  • the support circuit 203 routes power from an external source to the pitch circuit 204, the roll circuit 206, and the yaw circuit 208.
  • the support circuit 203 outputs the pitch angular rate measurement, the roll angular rate measurement, and the yaw angular rate measurement through an output interface.
  • the support circuit 203 in one example comprises a signal processor for processing the pitch angular rate measurement, the roll angular rate measurement, and the yaw angular rate measurement before outputting the pitch angular rate measurement, the roll angular rate measurement, and the yaw angular rate measurement.
  • Each sensor of the plurality of sensors 104, 106, 108, and 110 determines a value that corresponds to a measurement of the environmental characteristic.
  • the plurality of independent sensors determine a plurality of independent values.
  • each of the plurality of independent values is from a same, predetermined time.
  • the plurality of independent values are concomitant.
  • the processor 102 obtains the plurality of independent values from the plurality of sensors 104, 106, 108, and 110.
  • the values for the environmental characteristic comprise error terms, for example, a drift scaling factor, noise, and drift rate.
  • the processor 102 makes a determination of the environmental characteristic based on an average of the plurality of values to reduce an effect of the error terms, as will be appreciated by those skilled in the art.
  • the processor 102 in one example receives each value of the plurality of values at a same, pre-determined time.
  • the processor 102 determines a summation value for the plurality of values. For example, the processor 102 adds the concomitant values together to obtain the summation value.
  • the processor 102 multiplies each value of the plurality of values by a pre-determined weighting value. For example, where a first gyroscope is known to be more accurate than a second gyroscope, the processor 102 multiplies the value from the first gyroscope by a weighting value of two and multiplies the value from the second gyroscope by a weighting value of one. Thus, the processor 102 gives the first gyroscope a higher priority than the second gyroscope.
  • the processor 102 divides the summation value by a scaling value to obtain an average of the plurality of values.
  • the average comprises a weighted average.
  • the scaling value is equal to the number n of the plurality of sensors.
  • a scaling factor of the average of the plurality of values is equal to one.
  • the scaling value is smaller than the number n and the scaling factor is greater than one.
  • the scaling factor can be increased or decreased by adjusting the scaling value.
  • the processor 102 in one example outputs the average of the plurality of values to one or more of a navigation, control, and/or inertial guidance system, as will be appreciated by those skilled in the art.
  • the processor 102 determines the average of the plurality of concomitant values to reduce a number of error terms in the measurement of the environmental characteristic. For example, where an error term of a value from a first sensor is uncorrelated with a value from other sensors, the processor 102 determines the average to reduce a magnitude of the error term.
  • the error term may be reduced as a square root of the number n of sensors. For example, where the processor 102 employs four sensors, the error term is reduced by a factor of two. In another example where the processor 102 employs sixteen sensors, the error term is reduced by a factor of four. Since the processor 102 reduces the number of error terms by determining the average, a required level of quality for the sensors can be reduced. For example, a plurality of inexpensive MEMS gyroscopes can be used in place of a single, expensive gyroscope, as will be appreciated by those skilled in the art.
  • plots 302, 402, and 502 comprise plots of short term drift samples for one or more gyroscopes.
  • the plot 302 comprises a plot of a short term drift sample for a single gyroscope.
  • the short term drift is approximately seventy degrees per hour.
  • the plot 402 comprises four short term drift samples (Run 1, Run 2, Run 3, and Run 4) for the apparatus 100 where the plurality of n sensors comprises four gyroscopes.
  • the short term drift of Run 4 was the highest of the four samples and reduced to approximately forty degrees per hour, an improvement of approximately 1.75 times the single gyroscope sample of FIG. 3.
  • the plot 502 comprises a plot of a short term drift sample for the apparatus 100 where the plurality of n sensors comprises sixteen gyroscopes.
  • the short term drift was reduced to approximately twenty degrees per hour, an improvement of approximately 3.5 times the single gyroscope sample of FIG. 3.
  • histograms 602, 702, and 802 comprise sample histograms of a temperature coefficient for a plurality of accelerometers.
  • the histograms 602, 702, and 802 are based on approximately 110 individual accelerometer samples.
  • the histogram 602 shows that temperature coefficients for the individual accelerometers were approximately within a range of 1.1, between -0.4 and 0.7. Referring to FIG.
  • the apparatus 100 in one example comprises a plurality of components such as one or more of electronic components, hardware components, and computer software components. A number of such components can be combined or divided in the apparatus 100.
  • An exemplary component of the apparatus 100 employs and/or comprises a set and/or series of computer instructions written in or implemented with any of a number of programming languages, as will be appreciated by those skilled in the art.
  • the apparatus 100 in one example employs one or more computer-readable signal-bearing media.
  • the computer-readable signal-bearing media store software, firmware and/or assembly language for performing one or more portions of one or more embodiments of the invention.
  • Examples of a computer-readable signal-bearing medium for the apparatus 100 comprise the recordable data storage medium 114 of the processor 102.
  • the computer- readable signal-bearing medium for the apparatus 100 in one example comprise one or more of a magnetic, electrical, optical, biological, and atomic data storage medium.
  • the computer-readable signal-bearing medium comprise floppy disks, magnetic tapes, CD- ROMs, DVD-ROMs, hard disk drives, and electronic memory.
  • the computer-readable signal-bearing medium comprises a modulated carrier signal transmitted over a network comprising or coupled with the apparatus 100, for instance, one or more of a telephone network, a local area network (“LAN”), a wide area network (“WAN”), the Internet, and a wireless network.
  • a network comprising or coupled with the apparatus 100, for instance, one or more of a telephone network, a local area network (“LAN”), a wide area network (“WAN”), the Internet, and a wireless network.

Abstract

A processor of an apparatus in one example makes a determination of an environmental characteristic based on an average of a plurality of concomitant values that correspond to the environmental characteristic.

Description

IMPROVEMENT OF ENVIRONMENTAL CHARACTERISTIC DETERMINATION
TECHNICAL FIELD
The invention relates generally to signal processing and more particularly to error reduction in gyroscopes and accelerometers.
BACKGROUND
Electronic sensors are often used for measurement of environmental characteristics. Gyroscopes are capable of measuring inertial characteristics, such as angular rate and/or acceleration. In known inertial measurement units ("IMUs"), a single gyroscope is used for each range of motion that is to be measured. For example, IMUs employ a gyroscope for pitch, a gyroscope for roll, and a gyroscope for yaw. In some applications additional gyro(s) may be used for redundancy so that on the event of a gyro failure the redundant gyros(s) data may be used. Outputs from gyroscopes may be unstable due to error terms that vary over time.
Some error terms are caused by environmental changes to the gyroscope, such as temperature fluctuation, shock, and vibration. The error terms may or may not be correlated with each other and may or may not vary between gyroscopes. A specialized and more precise gyroscope may be used to reduce the error terms, but at a higher manufacturing cost. Thus, a need exists for reduced error terms in environmental characteristic measurements without higher manufacturing costs.
SUMMARY
The invention in one implementation encompasses an apparatus. The apparatus comprises: plurality of concomitant values indicative of an environmental characteristic; and a processor having a plurality of inputs for receiving the plurality of concomitant values and having an output that provides a determination of the environmental characteristic; wherein the processor determines the environmental characteristic based on a combination of the plurality of concomitant values. Another implementation of the invention encompasses a method. The method comprises: determining, via a plurality of independent electronic sensors, a plurality of independent, concomitant values indicative of an environmental characteristic; calculating, via a processor, an average of the plurality of independent, concomitant values of the environmental characteristic; and providing the average of the plurality of independent, concomitant values as a single value indicative of the environmental characteristic.
A further implementation of the invention encompasses an apparatus. The apparatus comprises an inertial measurement unit that provides a pitch angular rate measurement, a roll angular rate measurement, and a yaw angular rate measurement. The inertial measurement unit comprises: a pitch circuit that comprises a pitch processor and a plurality of independent pitch sensors; a roll circuit that comprises a roll processor and a plurality of independent roll sensors; and a yaw circuit that comprises a yaw processor and a plurality of independent yaw sensors. The pitch processor receives a plurality of concomitant pitch values from the plurality of independent pitch sensors. The pitch processor determines an average of the concomitant pitch values. The roll processor receives a plurality of concomitant roll values from the plurality of independent roll sensors. The roll processor determines an average of the concomitant roll values. The yaw processor receives a plurality of concomitant yaw values from the plurality of independent yaw sensors. The yaw processor determines an average of the concomitant yaw values. The inertial measurement unit provides the average of the concomitant pitch values as the pitch angular rate measurement. The inertial measurement unit provides the average of the concomitant roll values as the roll angular rate measurement. The inertial measurement unit provides the average of the concomitant yaw values as the yaw angular rate measurement.
DESCRIPTION OF THE DRAWINGS
Features of exemplary implementations of the invention will become apparent from the description, the claims, and the accompanying drawings in which: FIG. 1 is a representation of one implementation of an apparatus that comprises a circuit with a processor and a plurality of sensors.
FIG. 2 is a representation of another implementation of the apparatus of FIG. 1 that comprises a plurality of circuit boards.
FIG. 3 is a representation of an exemplary plot of short term drift for a single gyroscope.
FIG. 4 is a representation of exemplary plots of short term drift for the apparatus of FIG. 1 where the plurality of sensors comprises four gyroscopes.
FIG. 5 is a representation of an exemplary plot of short term drift for the apparatus of FIG. 1 where the plurality of sensors comprises sixteen gyroscopes. FIG. 6 is a representation of an exemplary histogram of temperature coefficient for individual accelerometers.
FIG. 7 is a representation of an exemplary histogram of temperature coefficient for the apparatus of FIG. 1 where the plurality of sensors comprises four accelerometers.
FIG. 8 is a representation of an exemplary histogram of temperature coefficient for the apparatus of FIG. 1 where the plurality of sensors comprises sixteen accelerometers. DETAILED DESCRIPTION
Turning to FIG. 1, an apparatus 100 in one example comprises a circuit 101. The circuit 101 in one example comprises a processor 102 and a plurality of n sensors, for example, sensors 104, 106, 108, and 110. The processor 102 in one example comprises a signal processor. For example, the processor 102 receives signals from the sensors 104, 106, 108, and 110. The processor 102 in one example comprises a digital signal processor. In another example, the processor 102 comprises an analog signal processor. In yet another example, the processor 102 comprises an analog/digital converter 112 ("A/D D/A") for conversion of signals between an analog format and a digital format. The processor 102 makes a determination of an environmental characteristic based on an average of a plurality of concomitant values that correspond to the environmental characteristic. The processor 102 in one example comprises an instance of a recordable data storage medium 114 ("RDSM"), as described herein.
The sensors 104, 106, 108, and 110 comprise electronic sensors. The sensors 104, 106, 108, and 110 serve to obtain a plurality of concomitant values that correspond to the environmental characteristic for the processor 102. For example, the sensors 104, 106, 108, and 110 measure the environmental characteristic. The environmental characteristic in one example comprises an inertial characteristic, for example, an angular rate or angular acceleration. In another example, the environmental characteristics comprise temperature, pressure, strain, electrical field strength, and/or magnetic field strength. The sensors 104, 106, 108, and 110 in one example comprise one or more gyroscopes for measuring the angular rate and/or one or more accelerometers for measuring the angular acceleration. In a further example, the sensors 104, 106, 108, and 110 comprise Micro-Electro-Mechanical Systems (MEMS) gyroscopes and/or accelerometers. The gyroscopes and/or accelerometer in one example are single- and/or multi-axis. In one example, the gyroscopes and/or accelerometers are oriented along a same axis. In another example, the gyroscopes and/or accelerometers are oriented along different axes. For example, the angular rates are mathematically combined through employment of relative scaling to obtain a measurement for a desired axis, as will be appreciated by those skilled in the art. The sensors 104, 106, 108, and 110 in one example comprise independent sensors.
For example, each of the sensors 104, 106, 108, and 110 provides a value that corresponds to a measurement of the environmental characteristic. The sensors 104, 106, 108, and 110 in one example provide the values at and/or from a pre-determined time. For example, the sensors 104, 106, 108, and 110 are synchronized with a pre-determined clock signal. In another example, the sensors 104, 106, 108, and 110 operate in real-time. For example, the sensors 104, 106, 108, and 110 provide a continuous output of the value. The sensors 104, 106, 108, and 110 in one example provide the values substantially in parallel, as will be appreciated by those skilled in the art.
Turning to FIG. 2, an inertial measurement unit 202 in one example comprises a plurality of circuits 101 and a support circuit 203. For example, each circuit 101 corresponds to a dimension of travel. In one example, the circuits 101 comprise a pitch circuit 204, a roll circuit 206, and a yaw circuit 208. The inertial measurement unit 202 employs the pitch circuit 204, the roll circuit 206, and the yaw circuit 208 to provide a pitch angular rate measurement, a roll angular rate measurement, and a yaw angular rate measurement, respectively. In one example, the pitch circuit 204, the roll circuit 206, and the yaw circuit 208 are functionally and electrically identical. For example, the pitch circuit 204, the roll circuit 206, and the yaw circuit 208 are oriented orthogonally to each other to provide the pitch angular rate measurement, the roll angular rate measurement, and the yaw angular rate measurement, as will be appreciated by those skilled in the art. The support circuit 203 is electrically coupled with the pitch circuit 204, the roll circuit 206, and the yaw circuit 208. The support circuit 203 in one example comprises one or more communication and/or power interfaces and support logic for the pitch circuit 204, the roll circuit 206, and the yaw circuit 208. In one example, the support circuit 203 routes power from an external source to the pitch circuit 204, the roll circuit 206, and the yaw circuit 208. In a further example, the support circuit 203 outputs the pitch angular rate measurement, the roll angular rate measurement, and the yaw angular rate measurement through an output interface. The support circuit 203 in one example comprises a signal processor for processing the pitch angular rate measurement, the roll angular rate measurement, and the yaw angular rate measurement before outputting the pitch angular rate measurement, the roll angular rate measurement, and the yaw angular rate measurement.
An illustrative description of exemplary operation of the apparatus 100 is presented, for explanatory purposes. Each sensor of the plurality of sensors 104, 106, 108, and 110 determines a value that corresponds to a measurement of the environmental characteristic. For example, the plurality of independent sensors determine a plurality of independent values. In one example, each of the plurality of independent values is from a same, predetermined time. For example, the plurality of independent values are concomitant. The processor 102 obtains the plurality of independent values from the plurality of sensors 104, 106, 108, and 110. The values for the environmental characteristic comprise error terms, for example, a drift scaling factor, noise, and drift rate. The processor 102 makes a determination of the environmental characteristic based on an average of the plurality of values to reduce an effect of the error terms, as will be appreciated by those skilled in the art.
The processor 102 in one example receives each value of the plurality of values at a same, pre-determined time. The processor 102 determines a summation value for the plurality of values. For example, the processor 102 adds the concomitant values together to obtain the summation value. In a further example, the processor 102 multiplies each value of the plurality of values by a pre-determined weighting value. For example, where a first gyroscope is known to be more accurate than a second gyroscope, the processor 102 multiplies the value from the first gyroscope by a weighting value of two and multiplies the value from the second gyroscope by a weighting value of one. Thus, the processor 102 gives the first gyroscope a higher priority than the second gyroscope.
The processor 102 divides the summation value by a scaling value to obtain an average of the plurality of values. Where the processor 102 employs weighting values as described above, the average comprises a weighted average. In one example, the scaling value is equal to the number n of the plurality of sensors. For example, a scaling factor of the average of the plurality of values is equal to one. In another example, the scaling value is smaller than the number n and the scaling factor is greater than one. The scaling factor can be increased or decreased by adjusting the scaling value. The processor 102 in one example outputs the average of the plurality of values to one or more of a navigation, control, and/or inertial guidance system, as will be appreciated by those skilled in the art.
The processor 102 in one example determines the average of the plurality of concomitant values to reduce a number of error terms in the measurement of the environmental characteristic. For example, where an error term of a value from a first sensor is uncorrelated with a value from other sensors, the processor 102 determines the average to reduce a magnitude of the error term. The error term may be reduced as a square root of the number n of sensors. For example, where the processor 102 employs four sensors, the error term is reduced by a factor of two. In another example where the processor 102 employs sixteen sensors, the error term is reduced by a factor of four. Since the processor 102 reduces the number of error terms by determining the average, a required level of quality for the sensors can be reduced. For example, a plurality of inexpensive MEMS gyroscopes can be used in place of a single, expensive gyroscope, as will be appreciated by those skilled in the art.
Turning to FIGS. 3-5, plots 302, 402, and 502 comprise plots of short term drift samples for one or more gyroscopes. Referring to FIG. 3, the plot 302 comprises a plot of a short term drift sample for a single gyroscope. The short term drift is approximately seventy degrees per hour. Referring to FIG. 4, the plot 402 comprises four short term drift samples (Run 1, Run 2, Run 3, and Run 4) for the apparatus 100 where the plurality of n sensors comprises four gyroscopes. The short term drift of Run 4 was the highest of the four samples and reduced to approximately forty degrees per hour, an improvement of approximately 1.75 times the single gyroscope sample of FIG. 3. Referring to FIG. 5, the plot 502 comprises a plot of a short term drift sample for the apparatus 100 where the plurality of n sensors comprises sixteen gyroscopes. The short term drift was reduced to approximately twenty degrees per hour, an improvement of approximately 3.5 times the single gyroscope sample of FIG. 3. Turning to FIGS. 6-8, histograms 602, 702, and 802 comprise sample histograms of a temperature coefficient for a plurality of accelerometers. The histograms 602, 702, and 802 are based on approximately 110 individual accelerometer samples. Referring to FIG. 6, the histogram 602 shows that temperature coefficients for the individual accelerometers were approximately within a range of 1.1, between -0.4 and 0.7. Referring to FIG. 7, sets of four randomly selected individual accelerometer samples were averaged. This reduced the range of temperature coefficients for the samples to approximately 0.62, between -0.22 and 0.40, an improvement of approximately 1.77 times the range of the individual accelerometer samples of FIG. 7. Referring to FIG. 8, sets of sixteen randomly selected individual accelerometer samples were averaged. This reduced the range of temperature coefficients for the samples to approximately 0.22, between 0.0 and 0.22, an improvement of approximately 5.0 times the range of the individual accelerometer samples of FIG. 6.
The apparatus 100 in one example comprises a plurality of components such as one or more of electronic components, hardware components, and computer software components. A number of such components can be combined or divided in the apparatus 100. An exemplary component of the apparatus 100 employs and/or comprises a set and/or series of computer instructions written in or implemented with any of a number of programming languages, as will be appreciated by those skilled in the art.
The apparatus 100 in one example employs one or more computer-readable signal-bearing media. The computer-readable signal-bearing media store software, firmware and/or assembly language for performing one or more portions of one or more embodiments of the invention. Examples of a computer-readable signal-bearing medium for the apparatus 100 comprise the recordable data storage medium 114 of the processor 102. The computer- readable signal-bearing medium for the apparatus 100 in one example comprise one or more of a magnetic, electrical, optical, biological, and atomic data storage medium. For example, the computer-readable signal-bearing medium comprise floppy disks, magnetic tapes, CD- ROMs, DVD-ROMs, hard disk drives, and electronic memory. In another example, the computer-readable signal-bearing medium comprises a modulated carrier signal transmitted over a network comprising or coupled with the apparatus 100, for instance, one or more of a telephone network, a local area network ("LAN"), a wide area network ("WAN"), the Internet, and a wireless network.
The steps or operations described herein are just exemplary. There may be many variations to these steps or operations without departing from the spirit of the invention. For instance, the steps may be performed in a differing order, or steps may be added, deleted, or modified. Although exemplary implementations of the invention have been depicted and described in detail herein, it will be apparent to those skilled in the relevant art that various modifications, additions, substitutions, and the like can be made without departing from the spirit of the invention and these are therefore considered to be within the scope of the invention as defined in the following claims.

Claims

CLAIMSWhat is claimed is:
1. An apparatus, comprising:
plurality of concomitant values indicative of an environmental characteristic; and a processor having a plurality of inputs for receiving the plurality of concomitant values and having an output that provides a determination of the environmental characteristic; wherein the processor determines the environmental characteristic based on a combination of the plurality of concomitant values.
2. The apparatus of claim 1, further comprising: a plurality of sensors that obtain the plurality of concomitant values that correspond to the environmental characteristic; and each of the plurality of sensors having an output operatively coupled to a respective input of the processor.
3. The apparatus of claim 2, wherein the plurality of sensors comprise independent sensors of the environmental characteristic.
4. The apparatus of claim 2, wherein the processor determines an average of the plurality of concomitant values in order to reduce error terms in the plurality of concomitant values.
5. The apparatus of claim 2, wherein the plurality of sensors comprise at least one gyroscope and at least one accelerometer.
6. The apparatus of claim 5, wherein the gyroscope is a Micro-Electro- Mechanical Systems gyroscope.
7. The apparatus of claim 5, wherein the accelerometer is a Micro-Electro- Mechanical Systems accelerometer.
8. The apparatus of claim 2, wherein the processor multiplies each of the plurality of concomitant values by at least one weighting value to determine a weighted average of the plurality of concomitant values.
9. The apparatus of claim 1, wherein the determination of the environmental characteristic comprises a determination of the environmental characteristic for a pre- determined time period; wherein the plurality of concomitant values comprise a plurality of concomitant values from the pre-determined time period.
10. The apparatus of claim 1, wherein the combination is an average of the plurality of concomitant values and wherein the average comprises a summation value divided by a scaling value; and wherein the summation value comprises a summation of the plurality of concomitant values, wherein the scaling value comprises a number of the plurality of concomitant values multiplied by a scaling factor.
11. The apparatus of claim 1, wherein the environmental characteristic comprises at least one of angular rate, angular acceleration, temperature, pressure, strain, electrical field strength, and magnetic field strength.
12. A method, comprising :
determining, via a plurality of independent electronic sensors, a plurality of independent, concomitant values indicative of an environmental characteristic; calculating, via a processor, an average of the plurality of independent, concomitant values of the environmental characteristic; and providing the average of the plurality of independent, concomitant values as a single value indicative of the environmental characteristic.
13. The method of claim 12, wherein the plurality of independent electronic sensors comprise at least one of gyroscopes and accelerometers.
14. The method of claim 12, wherein the plurality of independent electronic sensors comprise at least one of single-axis and/or multi-axis gyroscopes.
15. The method of claim 12, wherein the processor performs at least one of an analog-to-digital conversion and a digital-to-analog conversion on at least one of the plurality of independent, concomitant values before a determination of the average of the plurality of independent, concomitant values.
16. The method of claim 15, wherein the environmental characteristic comprises at least one of an angular rate and angular acceleration; wherein the processor provides the single value for the at least one of the angular rate and the angular acceleration to a navigation, control, and inertial guidance system.
17. An inertial measurement unit that provides a pitch angular rate measurement, a roll angular rate measurement, and a yaw angular rate measurement, comprising: a pitch circuit that comprises a pitch processor and a plurality of independent pitch sensors; a roll circuit that comprises a roll processor and a plurality of independent roll sensors; and a yaw circuit that comprises a yaw processor and a plurality of independent yaw sensors; wherein the pitch processor receives a plurality of concomitant pitch values from the plurality of independent pitch sensors ; wherein the pitch processor determines an average of the concomitant pitch values; wherein the roll processor receives a plurality of concomitant roll values from the plurality of independent roll sensors; wherein the roll processor determines an average of the concomitant roll values; wherein the yaw processor receives a plurality of concomitant yaw values from the plurality of independent yaw sensors; wherein the yaw processor determines an average of the concomitant yaw values; wherein the inertial measurement unit provides the average of the concomitant pitch values as the pitch angular rate measurement; wherein the inertial measurement unit provides the average of the concomitant roll values as the roll angular rate measurement; wherein the inertial measurement unit provides the average of the concomitant yaw values as the yaw angular rate measurement.
18. The inertial measurement unit of claim 17, wherein the pitch processor determines a weighted average of the concomitant pitch values; wherein the roll processor determines a weighted average of the concomitant roll values; wherein the yaw processor determines a weighted average of the concomitant yaw values.
19. The inertial measurement unit of claim 17, wherein each average of the plurality of concomitant values comprises a summation value divided by a scaling value; wherein the summation value comprises a summation of the plurality of concomitant values, wherein the scaling value comprises a number of the plurality of concomitant values multiplied by a scaling factor.
20. The inertial measurement unit of claim 17, wherein at least one of the plurality of independent pitch sensors, the plurality of independent roll sensors, and the plurality of independent yaw sensors comprise at least one Micro-Electro-Mechanical Systems gyroscope.
21. The inertial measurement unit of claim 17, wherein at least one of the plurality of independent pitch sensors, the plurality of independent roll sensors, and the plurality of independent yaw sensors comprise at least one Micro-Electro-Mechanical Systems accelerometer.
22. The inertial measurement unit of claim 17, wherein the inertial measurement unit provides the pitch angular rate measurement, the roll angular rate measurement, and the yaw angular rate measurement for at least one of a navigation, control, and inertial guidance system.
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Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7234539B2 (en) * 2003-07-10 2007-06-26 Gyrodata, Incorporated Method and apparatus for rescaling measurements while drilling in different environments
US7117605B2 (en) 2004-04-13 2006-10-10 Gyrodata, Incorporated System and method for using microgyros to measure the orientation of a survey tool within a borehole
US7650238B2 (en) * 2005-05-09 2010-01-19 Northrop Grumman Corporation Environmental characteristic determination
US20100243791A1 (en) * 2006-11-30 2010-09-30 Honeywell International Inc. Gyroscopic failure detection in a navigation device through sensor correlation
US8065085B2 (en) 2007-10-02 2011-11-22 Gyrodata, Incorporated System and method for measuring depth and velocity of instrumentation within a wellbore using a bendable tool
US8185312B2 (en) 2008-10-22 2012-05-22 Gyrodata, Incorporated Downhole surveying utilizing multiple measurements
US8095317B2 (en) 2008-10-22 2012-01-10 Gyrodata, Incorporated Downhole surveying utilizing multiple measurements
US8290744B2 (en) * 2009-01-14 2012-10-16 The Charles Stark Draper Laboratory, Inc. Integrated rate isolation sensor
US8065087B2 (en) 2009-01-30 2011-11-22 Gyrodata, Incorporated Reducing error contributions to gyroscopic measurements from a wellbore survey system
US8200436B2 (en) * 2009-07-15 2012-06-12 Schlumberger Technology Corporation Method and apparatus for wellbore survey using inertial sensors
US8762091B1 (en) 2010-06-08 2014-06-24 Thales Visionix, Inc. Inertial measurement system
US8825436B2 (en) 2011-03-09 2014-09-02 Moog Inc. Inertial sensing with spatially distributed sensor array and two dimensional data processing
US9229026B2 (en) * 2011-04-13 2016-01-05 Northrop Grumman Guaidance and Electronics Company, Inc. Accelerometer systems and methods
GB201120198D0 (en) 2011-11-23 2012-01-04 Cambridge Entpr Ltd MEMS inertial sensor and method of inertial sensing
US20130247663A1 (en) * 2012-03-26 2013-09-26 Parin Patel Multichannel Gyroscopic Sensor
CA3013763C (en) * 2016-02-03 2021-02-16 Vk Integrated Systems Firearm electronic system
US10365131B2 (en) * 2016-05-18 2019-07-30 Honeywell International Inc. Hybrid inertial measurement unit
WO2018098658A1 (en) * 2016-11-30 2018-06-07 深圳市大疆创新科技有限公司 Object testing method, device, and system

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0848231A1 (en) * 1994-06-08 1998-06-17 BODENSEEWERK GERÄTETECHNIK GmbH Inertial sensor unit
EP1231473A1 (en) * 2000-12-22 2002-08-14 STN ATLAS Elektronik GmbH Device for determining acceleration or angular rate

Family Cites Families (58)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4303978A (en) * 1980-04-18 1981-12-01 The Boeing Company Integrated-strapdown-air-data sensor system
US5225838A (en) * 1980-12-29 1993-07-06 Raytheon Company All weather tactical strike system (AWTSS) and method of operation
US4566327A (en) * 1982-04-21 1986-01-28 Rockwell International Corporation System and technique for bandwidth improvement in multifunction sensors
US7415126B2 (en) * 1992-05-05 2008-08-19 Automotive Technologies International Inc. Occupant sensing system
GB2146776B (en) * 1983-09-16 1986-07-30 Ferranti Plc Accelerometer systems
WO1986003584A1 (en) * 1984-12-10 1986-06-19 Pfister Gmbh Force measuring device
JPH0697176B2 (en) * 1986-12-17 1994-11-30 日本電装株式会社 Displacement amount display device using coil type gauge
IT1206845B (en) * 1987-01-16 1989-05-11 Fiat Auto Spa DEVICE FOR MEASURING THE FUEL LEVEL PRESENT IN THE TANK OF A VEHICLE AND RELATED PROCEDURE FOR USE
US5396326A (en) * 1989-04-03 1995-03-07 Northrop Grumman Corporation Two gimbal error averaging astro-inertial navigator
US5610815A (en) * 1989-12-11 1997-03-11 Caterpillar Inc. Integrated vehicle positioning and navigation system, apparatus and method
US5134393A (en) * 1990-04-02 1992-07-28 Henson H Keith Traffic control system
US6295870B1 (en) 1991-02-08 2001-10-02 Alliedsignal Inc. Triaxial angular rate and acceleration sensor
US6738697B2 (en) * 1995-06-07 2004-05-18 Automotive Technologies International Inc. Telematics system for vehicle diagnostics
JP3057470B2 (en) * 1994-04-15 2000-06-26 株式会社ユニシアジェックス Vehicle engine refueling determination device and fuel supply device
US7421321B2 (en) * 1995-06-07 2008-09-02 Automotive Technologies International, Inc. System for obtaining vehicular information
US5642280A (en) * 1995-02-03 1997-06-24 Kelsey-Hayes Company Method and system for determining and compensating for a faulty wheel speed input signal in a vehicle control system
US7110880B2 (en) * 1997-10-22 2006-09-19 Intelligent Technologies International, Inc. Communication method and arrangement
US6768944B2 (en) * 2002-04-09 2004-07-27 Intelligent Technologies International, Inc. Method and system for controlling a vehicle
US7202776B2 (en) * 1997-10-22 2007-04-10 Intelligent Technologies International, Inc. Method and system for detecting objects external to a vehicle
US6720920B2 (en) * 1997-10-22 2004-04-13 Intelligent Technologies International Inc. Method and arrangement for communicating between vehicles
US7085637B2 (en) * 1997-10-22 2006-08-01 Intelligent Technologies International, Inc. Method and system for controlling a vehicle
US5774829A (en) * 1995-12-12 1998-06-30 Pinterra Corporation Navigation and positioning system and method using uncoordinated beacon signals in conjunction with an absolute positioning system
JP3660051B2 (en) * 1996-04-19 2005-06-15 矢崎総業株式会社 Fuel tank fuel level measuring device
JPH09324690A (en) * 1996-06-03 1997-12-16 Mitsubishi Electric Corp Internal combustion engine control device
JP3116826B2 (en) * 1996-07-15 2000-12-11 トヨタ自動車株式会社 Preignition detection device
DE19721217C1 (en) * 1997-05-21 1998-08-27 Daimler Benz Aerospace Ag Appliance for calibrating several gyro systems
JP3911796B2 (en) * 1997-10-07 2007-05-09 日産自動車株式会社 Fuel cell system and control method thereof
US7796081B2 (en) * 1997-10-22 2010-09-14 Intelligent Technologies International, Inc. Combined imaging and distance monitoring for vehicular applications
US6243657B1 (en) * 1997-12-23 2001-06-05 Pii North America, Inc. Method and apparatus for determining location of characteristics of a pipeline
US6038025A (en) * 1998-04-09 2000-03-14 Honeywell Inc. Method for manufacturing of fiberoptic gyroscope by providing a flexible connector connected to the coil and remaining gyroscope elements
JP3949285B2 (en) * 1998-07-21 2007-07-25 株式会社エー・アンド・デイ electronic balance
AUPP532198A0 (en) * 1998-08-18 1998-09-10 Lockhart Gibson Pty Ltd trustee for The Argyll Family Trust & D.T.M. Australasia Pty Ltd jointly trading as Vigil Systems System for monitoring operator performance
US6257057B1 (en) * 1998-12-16 2001-07-10 L-3 Communications Corporation Epitaxial coriolis rate sensor
US6188645B1 (en) * 1999-06-11 2001-02-13 Geosensor Corporation Seismic sensor array with electrical-to optical transformers
US6474159B1 (en) * 2000-04-21 2002-11-05 Intersense, Inc. Motion-tracking
US6510732B1 (en) * 2000-07-28 2003-01-28 Harley-Davidson Motor Company Group, Inc. Method for determining the balancer condition of a balanced engine
US6546328B1 (en) * 2001-01-03 2003-04-08 Eaton Corporation Knock and misfire detection system
DE10115548C2 (en) * 2001-03-28 2003-11-06 Busch Dieter & Co Prueftech Measuring device for determining the spatial orientation of a body relative to a reference direction
JP2002296039A (en) * 2001-03-30 2002-10-09 Murata Mfg Co Ltd Gyro device and electronic device using the same
JP4560241B2 (en) * 2001-06-06 2010-10-13 富士通テン株式会社 Internal combustion engine knock determination device
US6644115B2 (en) * 2001-12-21 2003-11-11 Visteon Global Technologies, Inc. Method and device for indicating liquid volume in a tank
DE10201073A1 (en) * 2002-01-14 2003-07-31 Siemens Ag Method for processing a signal from a knocking sensor of an internal combustion engine allows flexible adaptation of knocking signal sampling frequency to engine operating conditions that can be applied to different engine types
DE10229428A1 (en) * 2002-07-01 2004-01-15 Sick Ag detector unit
US6904377B2 (en) 2003-03-17 2005-06-07 Northrop Grumman Corporation Method for measuring force-dependent gyroscope sensitivity
US7040922B2 (en) * 2003-06-05 2006-05-09 Analog Devices, Inc. Multi-surface mounting member and electronic device
EP1508776A1 (en) * 2003-08-18 2005-02-23 Saab Ab Autonomous velocity estimation and navigation
KR100514374B1 (en) * 2003-10-01 2005-09-13 현대자동차주식회사 Fuel leakage monitoring controlling method of vehicle
JP4456903B2 (en) * 2004-03-24 2010-04-28 日立アプライアンス株式会社 Weight sensor and cooking device equipped with the weight sensor
US7117605B2 (en) * 2004-04-13 2006-10-10 Gyrodata, Incorporated System and method for using microgyros to measure the orientation of a survey tool within a borehole
US7302316B2 (en) * 2004-09-14 2007-11-27 Brigham Young University Programmable autopilot system for autonomous flight of unmanned aerial vehicles
US7482193B2 (en) * 2004-12-20 2009-01-27 Honeywell International Inc. Injection-molded package for MEMS inertial sensor
US7650238B2 (en) * 2005-05-09 2010-01-19 Northrop Grumman Corporation Environmental characteristic determination
US20060250257A1 (en) * 2005-05-09 2006-11-09 Reynolds Christopher I Sensor orientation for environmental error reduction
US7491567B2 (en) * 2005-11-22 2009-02-17 Honeywell International Inc. MEMS device packaging methods
US7532992B2 (en) * 2006-01-20 2009-05-12 Teledyne Isco, Inc. Measuring apparatuses and methods of using them
US7434482B1 (en) * 2007-07-25 2008-10-14 Applied Technologies Associates, Inc. Feedback-controlled piezoelectric force measuring apparatus
US7698082B2 (en) * 2008-05-20 2010-04-13 Northrop Grumman Guidance And Electronics Company, Inc. Real time error determination for inertial instruments
US8380433B2 (en) * 2008-09-24 2013-02-19 Texas Instruments Incorporated Low-complexity tightly-coupled integration filter for sensor-assisted GNSS receiver

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0848231A1 (en) * 1994-06-08 1998-06-17 BODENSEEWERK GERÄTETECHNIK GmbH Inertial sensor unit
EP1231473A1 (en) * 2000-12-22 2002-08-14 STN ATLAS Elektronik GmbH Device for determining acceleration or angular rate

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