Processing method for motion measurement
First Claim
1. A processing method for motion measurement, comprising the steps of:
- (a) producing three-axis angular rate signals by an angular rate producer and three-axis acceleration signals by an acceleration producer;
(b) converting said three-axis angular rate signals into digital angular increments and converting said input three-axis acceleration signals into digital velocity increments in an angular increment and velocity increment producer;
(c) computing attitude and heading angle measurements using said three-axis digital angular increments and said three-axis velocity increments in an attitude and heading processor; and
(d) maintaining a predetermined operating temperature throughout said above steps, wherein said predetermined operating temperature is a constant designated temperature selected between 150°
F. and 185°
F.
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Abstract
A processing method for motion measurement, which is adapted to apply to output signals proportional to rotation and translational motion of a carrier, respectively from rate sensors and acceleration sensors, is more suitable for emerging MEMS rate and acceleration sensors. Compared with a conventional IMU, the processing method utilizes a feedforward open-loop signal processing scheme to obtain highly accurate motion measurements by means of signal digitizing, temperature control and compensation, sensor error and misalignment calibrations, attitude updating, and damping control loops, and dramatically shrinks the size of mechanical and electronic hardware and power consumption, meanwhile, obtains highly accurate motion measurements.
169 Citations
35 Claims
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1. A processing method for motion measurement, comprising the steps of:
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(a) producing three-axis angular rate signals by an angular rate producer and three-axis acceleration signals by an acceleration producer;
(b) converting said three-axis angular rate signals into digital angular increments and converting said input three-axis acceleration signals into digital velocity increments in an angular increment and velocity increment producer;
(c) computing attitude and heading angle measurements using said three-axis digital angular increments and said three-axis velocity increments in an attitude and heading processor; and
(d) maintaining a predetermined operating temperature throughout said above steps, wherein said predetermined operating temperature is a constant designated temperature selected between 150°
F. and 185°
F.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
(a.1) acquiring three-axis analog angular rate voltage signals from said angular producer, which are directly proportional to carrier angular rates, and (a.2) acquiring three-axis analog acceleration voltage signals from said acceleration producer, which are directly proportional to carrier accelerations.
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4. A processing method for motion measurement, as recited in claim 3 wherein said step (a) further comprises amplifying steps of amplifying said analog voltage signals input from said angular rate producer and said acceleration producer and suppressing noise signals residing within said analog voltage signals input from said angular rate producer and said acceleration producer.
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5. A processing method for motion measurement, as recited in claim 4, wherein said amplifying step comprises the steps of:
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(a.3) amplifying said three-axis analog angular rate voltage signals and said three-axis analog acceleration voltage signals by means of a first amplifier circuit and a second amplifier circuit respectively to form amplified three-axis analog angular rate signals and amplified three-axis analog acceleration signals respectively; and
(a.4) outputting said amplified three-axis analog angular rate signals and said amplified three-axis analog acceleration signals to a first integrator circuit and a second integrator circuit respectively.
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6. A processing method for motion measurement, as recited in claim 123, 4 or 5 wherein the step (b) further comprises the steps of:
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(b.1) integrating said three-axis analog angular rate voltage signals and said three-axis analog acceleration voltage signals for a predetermined time interval to accumulate said three-axis analog angular rate voltage signals and said three-axis analog acceleration voltage signals as a raw three-axis angular increment and a raw three-axis velocity increment for said predetermined time interval to achieve accumulated angular increments and accumulated velocity increments, for removing noise signals that are non-directly proportional to said carrier angular rate and acceleration within said three-axis analog angular rate voltage signals and said three-axis analog acceleration voltage signals, improving signal-to-noise ratio, and removing said high frequency signals in said three-axis analog angular rate voltage signals and said three-axis analog acceleration voltage signals;
(b.2) forming an angular reset voltage pulse and a velocity reset voltage pulse as an angular scale and a velocity scale respectively;
(b.3) measuring said voltage values of said three-axis accumulated angular increments and said three-axis accumulated velocity increments with said angular reset voltage pulse and said velocity reset voltage pulse respectively to acquire angular increment counts and velocity increment counts as a digital form of angular and velocity measurements respectively; and
(b.4) scaling said voltage values of said three-axis accumulated angular and velocity increments into real three-axis angular and velocity increment voltage values.
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7. A processing method for motion measurement, as recited in claim 1, wherein the step (d) further comprises the steps of:
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(db-1) producing temperature voltage signals by a thermal sensing producer to an analog/digital converter, (db-2) sampling said temperature voltage signals in said analog/digital converter and digitizing said sampled temperature voltage signals to digital signals which are output to said temperature controller, (db-3) computing digital temperature commands in a temperature controller using said input digital signals from said analog/digital converter, a temperature sensor scale factor, and a pre-determined operating temperature of said angular rate producer and acceleration producer, wherein said digital temperature commands are fed back to a digital/analog converter, and (db-4) converting said digital temperature commands input from said temperature controller in said digital/analog converter into analog signals which are output to a heater device to provide adequate heat for maintaining said predetermined operating temperature throughout said processing method.
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8. A processing method for motion measurement, as recited in claim 7, wherein in the step (db-1), said voltage signals acquired from said thermal sensing producer is amplified by a first amplifier circuit before outputting to said analog/digital converter, for amplifying said voltage signals and suppressing said noise residing in said voltage signals and improving said signal-to-noise ratio.
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9. A processing method for motion measurement, as recited in claim 8, wherein in the step (db-4), said input analog signals from said digital/analog converter for driving said heater device is amplified in a second amplifier circuit before outputting to said heater device.
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10. A processing method for motion measurement, as recited in claim 1, wherein the thermal controlling loop step (d) further comprises the steps of:
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(da-1) producing temperature signals by a thermal sensing producer;
(da-2) inputting said temperature signals to a thermal processor for computing temperature control commands using said temperature signals, a temperature scale factor, and a predetermined operating temperature of said angular rate producer and said acceleration producer 10;
(da-3) producing driving signals to a heater device using said temperature control commands; and
(da-4) outputting said driving signals to said heater device for controlling said heater device to provide adequate heat for maintaining said predetermined operating temperature throughout said processing method.
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11. A processing method for motion measurement, as recited in claim 10 wherein said angular rate producer and said acceleration producer are MEMS angular rate device array and acceleration device array and said outputting signals of said angular rate producer and said acceleration producer are analog voltage signals.
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12. A processing method for motion measurement, as recited in claim 11, wherein the step (a) further comprises the steps of:
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(a.1) acquiring three-axis analog angular rate voltage signals from said angular producer 5, which are directly proportional to carrier angular rates, and (a.2) acquiring three-axis analog acceleration voltage signals from said acceleration producer 10, which are directly proportional to carrier accelerations.
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13. A processing method for motion measurement, as recited in claim 12, wherein said step (a) further comprises amplifying steps of amplifying said analog voltage signals input from said angular rate producer and said acceleration producer and suppressing noise signals residing within said analog voltage signals input from said angular rate producer and said acceleration producer.
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14. A processing method for motion measurement, as recited in claim 13 wherein said amplifying step comprises the steps of:
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(a.3) amplifying said three-axis analog angular rate voltage signals and said three-axis analog acceleration voltage signals by means of a first amplifier circuit and a second amplifier circuit respectively to form amplified three-axis analog angular rate signals and amplified three-axis analog acceleration signals respectively; and
(a.4) outputting said amplified three-axis analog angular rate signals and said amplified three-axis analog acceleration signals to a first integrator circuit and a second integrator circuit respectively.
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15. A processing method for motion measurement, as recited in claim 10, 11, 12, or 14, wherein the step (b) further comprises the steps of:
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(b.1) integrating said three-axis analog angular rate voltage signals and said three-axis analog acceleration voltage signals for a predetermined time interval to accumulate said three-axis analog angular rate voltage signals and said three-axis analog acceleration voltage signals as a raw three-axis angular increment and a raw three-axis velocity increment for said predetermined time interval to achieve accumulated angular increments and accumulated velocity increments, for removing noise signals that are non-directly proportional to said carrier angular rate and acceleration within said three-axis analog angular rate voltage signals and said three-axis analog acceleration voltage signals, improving signal-to-noise ratio, and removing said high frequency signals in said three-axis analog angular rate voltage signals and said three-axis analog acceleration voltage signals;
(b.2) forming an angular reset voltage pulse and a velocity reset voltage pulse as an angular scale and a velocity scale respectively;
(b.3) measuring said voltage values of said three-axis accumulated angular increments and said three-axis accumulated velocity increments with said angular reset voltage pulse and said velocity reset voltage pulse respectively to acquire angular increment counts and velocity increment counts as a digital form of angular and velocity measurements respectively; and
(b.4) scaling said voltage values of said three-axis accumulated angular and velocity increments into real three-axis angular and velocity increment voltage values.
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16. A processing method for motion measurement, as recited in claim 10 wherein temperature characteristic parameters of said angular rate producer and said acceleration producer are determined during a series of said angular rate producer and acceleration producer temperature characteristic calibrations.
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17. A processing method for motion measurement, as recited in claim 1 or 10, wherein in order to adapt to digital three-axis angular increment voltage value and three-axis digital velocity increment voltage values from said step (b), the step (c) further comprises the steps of:
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(cb.1) inputting digital three-axis angular increment voltage values from said input/output interface circuit of said step (b) and coarse angular rate bias obtained from an angular rate producer and acceleration producer calibration procedure in high data rate for a short interval into a coning correction module;
computing coning effect errors in said coning correction module using said input digital three-axis angular increment voltage values and coarse angular rate bias; and
outputting three-axis coning effect terms and three-axis angular increment voltage values at reduced data rate for a long interval, which are called three-axis long-interval angular increment voltage values, into a angular rate compensation module,(cb.2) inputting said coning effect errors and three-axis long-interval angular increment voltage values from said coning correction module and angular rate device misalignment parameters, fine angular rate bias, angular rate device scale factor, and coning correction scale factor from said angular rate producer and acceleration producer calibration procedure to said angular rate compensation module;
compensating definite errors in said input three-axis long-interval angular increment voltage values using said input coning effect errors, angular rate device misalignment parameters, fine angular rate bias, and coning correction scale factor;
transforming said compensated three-axis long-interval angular increment voltage values to real three-axis long-interval angular increments using said angular rate device scale factor; and
outputting said real three-axis angular increments to an alignment rotation vector computation module,(cb.3) inputting said three-axis velocity increment voltage values from said input/output interface circuit of said step (b) and acceleration device misalignment, acceleration device bias, and acceleration device scale factor from said angular rate producer and acceleration producer calibration procedure to accelerometer compensation module;
transforming said input three-axis velocity increments voltage values into real three-axis velocity increments using said acceleration device scale factor;
compensating said definite errors in three-axis velocity increments using said input acceleration device misalignment, accelerometer bias;
outputting said compensated three-axis velocity increments to said level acceleration computation module,(cb.4) updating a quaternion, which is a vector representing rotation motion of said carrier, using said compensated three-axis angular increments from said angular rate compensation module, an east damping rate increment from an east damping computation module, a north damping rate increment from a north damping computation module, and vertical damping rate increment from a vertical damping computation module; and
said updated quaternion is output to a direction cosine matrix computation module,(cb.5) computing said direction cosine matrix, using said input updated quaternion; and
said computed direction cosine matrix is output to a level acceleration computation module and an attitude and heading angle extract module,(cb.6) extracting attitude and heading angle using said direction cosine matrix from said direction cosine matrix computation module;
outputting said heading angle into a vertical damping rate computation module,(cb.7) computing level velocity increments using said input compensated three-axis velocity increments from said acceleration compensation module and said direction cosine matrix from said direction cosine matrix computation module;
outputting said level velocity increments to an east damping rate computation module and north damping rate computation module,(cb.8) computing east damping rate increments using said north velocity increment of said input level velocity increments from said level acceleration computation module;
feeding back said east damping rate increments to said alignment rotation vector computation module,(cb.9) computing north damping rate increments using said east velocity increment of said input level velocity increments from said level acceleration computation module;
feeding back said north damping rate increments to said alignment rotation vector computation module, and(cb.10) computing vertical damping rate increments using said computed heading angle from said attitude and heading angle extract module and a measured heading angle from an external sensor; and
feeding back said vertical damping rate increments to said alignment rotation vector computation module.
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18. A processing method for motion measurement, as recited in claim 1 or 10 wherein in order to adapt to digital three-axis angular increment voltage value and three-axis digital velocity increment voltage values from said step (b), the step (c) further comprises the steps of:
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(cb.1) inputting real digital three-axis angular increment values from said step (b) and coarse angular rate bias obtained from an angular rate producer and acceleration producer calibration procedure in high data rate for a short interval into a coning correction module;
computing coning effect errors in said coning correction module using said input digital three-axis angular increment values and coarse angular rate bias; and
outputting three-axis coning effect terms and three-axis angular increment values at reduced data rate (long interval), which are called three-axis long-interval angular increment values, into a angular rate compensation module,(cb.2) inputting said coning effect errors and three-axis long-interval angular increment values from said coning correction module and angular rate device misalignment parameters and fine angular rate bias from said angular rate producer and acceleration producer calibration procedure to said angular rate compensation module;
compensating definite errors in said input three-axis long-interval angular increment values using said input coning effect errors, angular rate device misalignment parameters, fine angular rate bias, and coning correction scale factor; and
outputting said real three-axis angular increments to an alignment rotation vector computation module,(cb.3) inputting said three-axis velocity increment values from the step (b) and acceleration device misalignment, and acceleration device bias from said angular rate producer and acceleration producer calibration procedure to accelerometer compensation module;
compensating said definite errors in three-axis velocity increments using said input acceleration device misalignment, accelerometer bias;
outputting said compensated three-axis velocity increments to said level acceleration computation module,(cb.4) updating a quaternion, which is a vector representing rotation motion of said carrier, using said compensated three-axis angular increments from said angular rate compensation module, an east damping rate increment from an east damping computation module, a north damping rate increment from a north damping computation module, and vertical damping rate increment from a vertical damping computation module; and
said updated quaternion is output to a direction cosine matrix computation module,(cb.5) computing said direction cosine matrix, using said input updated quaternion; and
said computed direction cosine matrix is output to a level acceleration computation module and an attitude and heading angle extract module,(cb.6) extracting attitude and heading angle using said direction cosine matrix from said direction cosine matrix computation module;
outputting said heading angle into a vertical damping rate computation module,(cb.7) computing level velocity increments using said input compensated three-axis velocity increments from said acceleration compensation module and said direction cosine matrix from said direction cosine matrix computation module;
outputting said level velocity increments to an east damping rate computation module and north damping rate computation module,(cb.8) computing east damping rate increments using said north velocity increment of said input level velocity increments from said level acceleration computation module;
feeding back said east damping rate increments to said alignment rotation vector computation module,(cb.9) computing north damping rate increments using said east velocity increment of said input level velocity increments from said level acceleration computation module;
feeding back said north damping rate increments to said alignment rotation vector computation module, and(cb.10) computing vertical damping rate increments using said computed heading angle from said attitude and heading angle extract module and a measured heading angle from an external sensor; and
feeding back said vertical damping rate increments to said alignment rotation vector computation module.
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19. A processing method for motion measurement, as recited in claim 1 or 10 wherein the step (ca-2) further comprises the steps of:
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(ca-2.1) inputting digital three-axis angular increment voltage values from said input/output interface circuit of said step (b) and coarse angular rate bias obtained from an angular rate producer and acceleration producer calibration procedure in high data rate for a short interval into a coning correction module;
computing coning effect errors in said coning correction module using said input digital three-axis angular increment voltage values and coarse angular rate bias; and
outputting three-axis coning effect terms and three-axis angular increment voltage values in reduced data rate for a long interval, which are called three-axis long-interval angular increment voltage values, into a angular rate compensation module,(ca-2.2) inputting said coning effect errors and three-axis long-interval angular increment voltage values from said coning correction module and angular rate device misalignment parameters, fine angular rate bias, angular rate device scale factor, and coning correction scale factor from said angular rate producer and acceleration producer calibration procedure to said angular rate compensation module;
inputting said digital temperature signals from input/output interface circuit of said step (ca-1.2) and temperature sensor scale factor;
computing current temperature of angular rate producer;
accessing angular rate producer temperature characteristic parameters using said current temperature of angular rate producer;
compensating definite errors in said input three-axis long-interval angular increment voltage values using said input coning effect errors, angular rate device misalignment parameters, fine angular rate bias, and coning correction scale factor;
transforming said compensated three-axis long-interval angular increment voltage values to real three-axis long-interval angular increments;
compensating temperature-induced errors in said real three-axis long-interval angular increments using said angular rate producer temperature characteristic parameters; and
outputting said real three-axis angular increments to an alignment rotation vector computation module,(ca-2.3) inputting said three-axis velocity increment voltage values from said input/output interface circuit of said step (b) and acceleration device misalignment, acceleration bias, acceleration device scale factor from said angular rate producer and acceleration producer calibration procedure to acceleration compensation module;
inputting said digital temperature signals from input/output interface circuit of said step (ca-1) and temperature sensor scale factor;
computing current temperature of acceleration producer;
accessing acceleration producer temperature characteristic parameters using said current temperature of acceleration producer;
transforming said input three-axis velocity increments voltage values into real three-axis velocity increments using said acceleration device scale factor;
compensating said definite errors in three-axis velocity increments using said input acceleration device misalignment, acceleration bias;
compensating temperature-induced errors in said real three-axis velocity increments using said acceleration producer temperature characteristic parameters; and
outputting said compensated three-axis velocity increments to said level acceleration computation module,(ca-2.4) updating a quaternion, which is a vector representing rotation motion of said carrier, using said compensated three-axis angular increments from said angular rate compensation module, an east damping rate increment from an east damping computation module, a north damping rate increment from a north damping computation module, and vertical damping rate increment from a vertical damping computation module; and
said updated quaternion is output to a direction cosine matrix computation module,(ca-2.5) computing said direction cosine matrix, using said input updated quaternion; and
said computed direction cosine matrix is output to a level acceleration computation module and an attitude and heading angle extract module,(ca-2.6) extracting attitude and heading angle using said direction cosine matrix from said direction cosine matrix computation module;
outputting said heading angle into a vertical damping rate computation module,(ca-2.7) computing level velocity increments using said input compensated three-axis velocity increments from said acceleration compensation module and said direction cosine matrix from said direction cosine matrix computation module;
outputting said level velocity increments to an east damping rate computation module and north damping rate computation module,(ca-2.8) computing east damping rate increments using said north velocity increment of said input level velocity increments from said level acceleration computation module;
feeding back said east damping rate increments to said alignment rotation vector computation module,(ca-2.9) computing north damping rate increments using said east velocity increment of said input level velocity increments from said level acceleration computation module;
feeding back said north damping rate increments to said alignment rotation vector computation module, and(ca-2.10) computing vertical damping rate increments using said computed heading angle from said attitude and heading angel extract module and a measured heading angle from an external sensor; and
feeding back said vertical damping rate increments to said alignment rotation vector computation module.
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20. A processing method for motion measurement, as recited in claim 1 or 10, wherein the step (ca-2) further comprises the steps of:
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(ca-2.1) inputting digital three-axis angular increment values from said input/output interface circuit of the step (b) and coarse angular rate bias obtained from an angular rate producer and acceleration producer calibration procedure in high data rate for a short interval into a coning correction module;
computing coning effect errors in said coning correction module using said input digital three-axis angular increment values and coarse angular rate bias; and
outputting three-axis coning effect terms and three-axis angular increment values in reduced data rate for a long interval, which are called three-axis long-interval angular increment values, into a angular rate compensation module,(ca-2.2) inputting said coning effect errors and three-axis long-interval angular increment values from said coning correction module and angular rate device misalignment parameters and fine angular rate bias from said angular rate producer and acceleration producer calibration procedure to said angular rate compensation module;
inputting said digital temperature signals from input/output interface circuit of said step (ca-1.2) and temperature sensor scale factor;
computing current temperature of angular rate producer;
accessing angular rate producer temperature characteristic parameters using said current temperature of angular rate producer;
compensating definite errors in said input three-axis long-interval angular increment values using said input coning effect errors, angular rate device misalignment parameters, fine angular rate bias, and coning correction scale factor;
compensating temperature-induced errors in said real three-axis long-interval angular increments using said angular rate producer temperature characteristic parameters; and
outputting said real three-axis angular increments to an alignment rotation vector computation module,(ca-2.3) inputting said three-axis velocity increment values from said input/output interface circuit of said step (b) and acceleration device misalignment and acceleration bias from said angular rate producer and acceleration producer calibration procedure to acceleration compensation module;
inputting said digital temperature signals from input/output interface circuit of said step (ca-1) and temperature sensor scale factor;
computing current temperature of acceleration producer;
accessing acceleration producer temperature characteristic parameters using said current temperature of acceleration producer;
compensating said definite errors in three-axis velocity increments using said input acceleration device misalignment, acceleration bias;
compensating temperature-induced errors in said real three-axis velocity increments using said acceleration producer temperature characteristic parameters; and
outputting said compensated three-axis velocity increments to said level acceleration computation module,(ca-2.4) updating a quaternion, which is a vector representing rotation motion of said carrier, using said compensated three-axis angular increments from said angular rate compensation module, an east damping rate increment from an east damping computation module, a north damping rate increment from a north damping computation module, and vertical damping rate increment from a vertical damping computation module; and
said updated quaternion is output to a direction cosine matrix computation module,(ca-2.5) computing said direction cosine matrix, using said input updated quaternion; and
said computed direction cosine matrix is output to a level acceleration computation module and an attitude and heading angle extract module,(ca-2.6) extracting attitude and heading angle using said direction cosine matrix from said direction cosine matrix computation module;
outputting said heading angle into a vertical damping rate computation module,(ca-2.7) computing level velocity increments using said input compensated three-axis velocity increments from said acceleration compensation module and said direction cosine matrix from said direction cosine matrix computation module;
outputting said level velocity increments to an east damping rate computation module and north damping rate computation module,(ca-2.8) computing east damping rate increments using said north velocity increment of said input level velocity increments from said level acceleration computation module;
feeding back said east damping rate increments to said alignment rotation vector computation module,(ca-2.9) computing north damping rate increments using said east velocity increment of said input level velocity increments from said level acceleration computation module;
feeding back said north damping rate increments to said alignment rotation vector computation module, and(ca-2.10) computing vertical damping rate increments using said computed heading angle from said attitude and heading angel extract module and a measured heading angle from an external sensor; and
feeding back said vertical damping rate increments to said alignment rotation vector computation module.
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21. A processing method for motion measurement, as recited in claim 1, wherein the step (d) further comprises the steps of:
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(db-1) producing temperature voltage signals by a thermal sensing producer to an analog/digital converter, (db-2) sampling said temperature voltage signals in said analog/digital converter and digitizing said sampled voltage signals, wherein said digital signals are output to an input/output interface circuit;
(db-3) computing digital temperature commands in a temperature controller using said input digital temperature voltage signals from said input/output interface circuit, a temperature sensor scale factor, and said predetermined operating temperature of said angular rate producer and acceleration producer, wherein said digital temperature commands are fed back to said input/output interface circuit; and
(db-4) converting said digital temperature commands input from said input/output interface circuit in said digital/analog converter into analog signals which are output to a heater device to provide adequate heat for maintaining said predetermined operating temperature throughout said processing method.
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22. A processing method for motion measurement, as recited in claim 21, wherein in the step (db-1), said voltage signals acquired from said thermal sensing producer is amplified by a first amplifier circuit before outputting to said analog/digital converter, for amplifying said voltage signals and suppressing said noise residing in said voltage signals and improving said signal-to-noise ratio.
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23. A processing method for motion measurement, as recited in claim 22, wherein in the step (db-4), said input analog signals from said digital/analog converter for driving said heater device is amplified in a second amplifier circuit before outputting to said heater device.
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24. A processing method for motion measurement, comprising the steps of:
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(a) producing three-axis angular rate signals by an angular rate producer and three-axis acceleration signals by an acceleration producer;
(b) converting said three-axis angular rate signals into digital angular increments and converting said input three-axis acceleration signals into digital velocity increments in an angular increment and velocity increment producer;
(c) computing attitude and heading angle measurements, using said three-axis digital angular increments and said three-axis velocity increments in an attitude and heading processor;
(ca-1) producing temperature signals by a thermal sensing producer and outputting a digital temperature value to an attitude and heading processor 80 by means of a temperature digitizer;
(ca-2) accessing temperature characteristic parameters of said angular rate producer and said acceleration producer using a current temperature of said angular rate producer and said acceleration producer from said temperature digitizer; and
(ca-3) compensating said errors induced by thermal effects in said input digital angular and velocity increments and computing attitude and heading angle measurements using said three-axis digital angular increments and three-axis velocity increments in said attitude and heading processor. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
(a.1) acquiring three-axis analog angular rate voltage signals from said angular producer, which are directly proportional to carrier angular rates, and (a.2) acquiring three-axis analog acceleration voltage signals from said acceleration producer, which are directly proportional to carrier accelerations.
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27. A processing method for motion measurement, as recited in claim 26, wherein said step (a) further comprises an amplifying step of amplifying said analog voltage signals input from said angular rate producer and said acceleration producer and suppressing noise signals residing within said analog voltage signals input from said angular rate producer and said acceleration producer.
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28. A processing method for motion measurement, as recited in claim 27, wherein said amplifying step comprises the steps of:
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(a.3) amplifying said three-axis analog angular rate voltage signals and said three-axis analog acceleration voltage signals by means of a first amplifier circuit and a second amplifier circuit respectively to form amplified three-axis analog angular rate signals and amplified three-axis analog acceleration signals respectively; and
(a.4) outputting said amplified three-axis analog angular rate signals and said amplified three-axis analog acceleration signals to a first integrator circuit and a second integrator circuit respectively.
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29. A processing method for motion measurement, as recited in claim 24, 2526 or 28, wherein the step (b) further comprises the steps of:
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(b.1) integrating said three-axis analog angular rate voltage signals and said three-axis analog acceleration voltage signals for a predetermined time interval to accumulate said three-axis analog angular rate voltage signals and said three-axis analog acceleration voltage signals as a raw three-axis angular increment and a raw three-axis velocity increment for said predetermined time interval to achieve accumulated angular increments and accumulated velocity increments, for removing noise signals that are non-directly proportional to said carrier angular rate and acceleration within said three-axis analog angular rate voltage signals and said three-axis analog acceleration voltage signals, improving signal-to-noise ratio, and removing said high frequency signals in said three-axis analog angular rate voltage signals and said three-axis analog acceleration voltage signals;
(b.2) forming an angular reset voltage pulse and a velocity reset voltage pulse as an angular scale and a velocity scale respectively;
(b.3) measuring said voltage values of said three-axis accumulated angular increments and said three-axis accumulated velocity increments with said angular reset voltage pulse and said velocity reset voltage pulse respectively to acquire angular increment counts and velocity increment counts as a digital form of angular and velocity measurements respectively; and
(b.4) scaling said voltage values of said three-axis accumulated angular and velocity increments into real three-axis angular and velocity increment voltage values.
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30. A processing method for motion measurement, as recited in claim 24, wherein the step (ca-1) is implemented by an analog/digital converter for said thermal sensing producer with analog voltage output and further comprises the steps of:
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(ca-1.1) acquiring voltage signals from said thermal sensing producer to said amplifier circuit for amplifying said signals and suppressing said noise residing in said voltage signals and improving said voltage signal-to-noise ratio, wherein said amplified voltage signals are output to said analog/digital converter, and (ca-1.2) sampling said input amplified voltage signals in said analog/digital converters and digitizing said sampled voltage signals to form digital signals outputting to said attitude and heading processor.
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31. A processing method for motion measurement, as recited in claim 30 wherein the step (ca-1.2) further comprises the steps of:
(ca-1.2a) sampling said input amplified voltage signals in said analog/digital converters and digitizing said sampled voltage signals to form digital signals outputting to said input/output interface circuit.
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32. A processing method for motion measurement, as recited in claim 24, wherein in order to adapt to digital three-axis angular increment voltage value and three-axis digital velocity increment voltage values from said step (b), the step (c) further comprises the steps of:
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(cb.1) inputting digital three-axis angular increment voltage values from said input/output interface circuit of said step (b) and coarse angular rate bias obtained from an angular rate producer and acceleration producer calibration procedure in high data rate for a short interval into a coning correction module;
computing coning effect errors in said coning correction module using said input digital three-axis angular increment voltage values and coarse angular rate bias; and
outputting three-axis coning effect terms and three-axis angular increment voltage values at reduced data rate for a long interval, which are called three-axis long-interval angular increment voltage values, into a angular rate compensation module,(cb.2) inputting said coning effect errors and three-axis long-interval angular increment voltage values from said coning correction module and angular rate device misalignment parameters, fine angular rate bias, angular rate device scale factor, and coning correction scale factor from said angular rate producer and acceleration producer calibration procedure to said angular rate compensation module;
compensating definite errors in said input three-axis long-interval angular increment voltage values using said input coning effect errors, angular rate device misalignment parameters, fine angular rate bias, and coning correction scale factor;
transforming said compensated three-axis long-interval angular increment voltage values to real three-axis long-interval angular increments using said angular rate device scale factor; and
outputting said real three-axis angular increments to an alignment rotation vector computation module,(cb.3) inputting said three-axis velocity increment voltage values from said input/output interface circuit of said step (b) and acceleration device misalignment, acceleration device bias, and acceleration device scale factor from said angular rate producer and acceleration producer calibration procedure to accelerometer compensation module;
transforming said input three-axis velocity increments voltage values into real three-axis velocity increments using said acceleration device scale factor;
compensating said definite errors in three-axis velocity increments using said input acceleration device misalignment, accelerometer bias;
outputting said compensated three-axis velocity increments to said level acceleration computation module,(cb.4) updating a quaternion, which is a vector representing rotation motion of said carrier, using said compensated three-axis angular increments from said angular rate compensation module, an east damping rate increment from an east damping computation module, a north damping rate increment from a north damping computation module, and vertical damping rate increment from a vertical damping computation module; and
said updated quaternion is output to a direction cosine matrix computation module,(cb.5) computing said direction cosine matrix, using said input updated quaternion; and
said computed direction cosine matrix is output to a level acceleration computation module and an attitude and heading angle extract module,(cb.6) extracting attitude and heading angle using said direction cosine matrix from said direction cosine matrix computation module;
outputting said heading angle into a vertical damping rate computation module,(cb.7) computing level velocity increments using said input compensated three-axis velocity increments from said acceleration compensation module and said direction cosine matrix from said direction cosine matrix computation module;
outputting said level velocity increments to an east damping rate computation module and north damping rate computation module,(cb.8) computing east damping rate increments using said north velocity increment of said input level velocity increments from said level acceleration computation module;
feeding back said east damping rate increments to said alignment rotation vector computation module,(cb.9) computing north damping rate increments using said east velocity increment of said input level velocity increments from said level acceleration computation module;
feeding back said north damping rate increments to said alignment rotation vector computation module, and(cb.10) computing vertical damping rate increments using said computed heading angle from said attitude and heading angle extract module and a measured heading angle from an external sensor; and
feeding back said vertical damping rate increments to said alignment rotation vector computation module.
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33. A processing method for motion measurement, as recited in claim 24 wherein in order to adapt to digital three-axis angular increment voltage value and three-axis digital velocity increment voltage values from said step (b), the step (c) further comprises the steps of:
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(cb.1) inputting real digital three-axis angular increment values from said step (b) and coarse angular rate bias obtained from an angular rate producer and acceleration producer calibration procedure in high data rate for a short interval into a coning correction module;
computing coning effect errors in said coning correction module using said input digital three-axis angular increment values and coarse angular rate bias; and
outputting three-axis coning effect terms and three-axis angular increment values at reduced data rate (long interval), which are called three-axis long-interval angular increment values, into a angular rate compensation module,(cb.2) inputting said coning effect errors and three-axis long-interval angular increment values from said coning correction module and angular rate device misalignment parameters and fine angular rate bias from said angular rate producer and acceleration producer calibration procedure to said angular rate compensation module;
compensating definite errors in said input three-axis long-interval angular increment values using said input coning effect errors, angular rate device misalignment parameters, fine angular rate bias, and coning correction scale factor; and
outputting said real three-axis angular increments to an alignment rotation vector computation module,(cb.3) inputting said three-axis velocity increment values from the step (b) and acceleration device misalignment, and acceleration device bias from said angular rate producer and acceleration producer calibration procedure to accelerometer compensation module;
compensating said definite errors in three-axis velocity increments using said input acceleration device misalignment, accelerometer bias;
outputting said compensated three-axis velocity increments to said level acceleration computation module,(cb.4) updating a quaternion, which is a vector representing rotation motion of said carrier, using said compensated three-axis angular increments from said angular rate compensation module, an east damping rate increment from an east damping computation module, a north damping rate increment from a north damping computation module, and vertical damping rate increment from a vertical damping computation module; and
said updated quaternion is output to a direction cosine matrix computation module,(cb.5) computing said direction cosine matrix, using said input updated quaternion; and
said computed direction cosine matrix is output to a level acceleration computation module and an attitude and heading angle extract module,(cb.6) extracting attitude and heading angle using said direction cosine matrix from said direction cosine matrix computation module;
outputting said heading angle into a vertical damping rate computation module,(cb.7) computing level velocity increments using said input compensated three-axis velocity increments from said acceleration compensation module and said direction cosine matrix from said direction cosine matrix computation module;
outputting said level velocity increments to an east damping rate computation module and north damping rate computation module,(cb.8) computing east damping rate increments using said north velocity increment of said input level velocity increments from said level acceleration computation module;
feeding back said east damping rate increments to said alignment rotation vector computation module,(cb.9) computing north damping rate increments using said east velocity increment of said input level velocity increments from said level acceleration computation module;
feeding back said north damping rate increments to said alignment rotation vector computation module, and(cb.10) computing vertical damping rate increments using said computed heading angle from said attitude and heading angle extract module and a measured heading angle from an external sensor; and
feeding back said vertical damping rate increments to said alignment rotation vector computation module.
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34. A processing method for motion measurement, as recited in claim 24, wherein the step (ca-2) further comprises the steps of:
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(ca-2.1) inputting digital three-axis angular increment voltage values from said input/output interface circuit of said step (b) and coarse angular rate bias obtained from an angular rate producer and acceleration producer calibration procedure in high data rate for a short interval into a coning correction module;
computing coning effect errors in said coning correction module using said input digital three-axis angular increment voltage values and coarse angular rate bias; and
outputting three-axis coning effect terms and three-axis angular increment voltage values in reduced data rate for a long interval, which are called three-axis long-interval angular increment voltage values, into a angular rate compensation module,(ca-2.2) inputting said coning effect errors and three-axis long-interval angular increment voltage values from said coning correction module and angular rate device misalignment parameters, fine angular rate bias, angular rate device scale factor, and coning correction scale factor from said angular rate producer and acceleration producer calibration procedure to said angular rate compensation module;
inputting said digital temperature signals from input/output interface circuit of said step (ca-1.2) and temperature sensor scale factor;
computing current temperature of angular rate producer;
accessing angular rate producer temperature characteristic parameters using said current temperature of angular rate producer;
compensating definite errors in said input three-axis long-interval angular increment voltage values using said input coning effect errors, angular rate device misalignment parameters, fine angular rate bias, and coning correction scale factor;
transforming said compensated three-axis long-interval angular increment voltage values to real three-axis long-interval angular increments;
compensating temperature-induced errors in said real three-axis long-interval angular increments using said angular rate producer temperature characteristic parameters; and
outputting said real three-axis angular increments to an alignment rotation vector computation module,(ca-2.3) inputting said three-axis velocity increment voltage values from said input/output interface circuit of said step (b) and acceleration device misalignment, acceleration bias, acceleration device scale factor from said angular rate producer and acceleration producer calibration procedure to acceleration compensation module;
inputting said digital temperature signals from input/output interface circuit of said step (ca-1) and temperature sensor scale factor;
computing current temperature of acceleration producer;
accessing acceleration producer temperature characteristic parameters using said current temperature of acceleration producer;
transforming said input three-axis velocity increments voltage values into real three-axis velocity increments using said acceleration device scale factor;
compensating said definite errors in three-axis velocity increments using said input acceleration device misalignment, acceleration bias;
compensating temperature-induced errors in said real three-axis velocity increments using said acceleration producer temperature characteristic parameters; and
outputting said compensated three-axis velocity increments to said level acceleration computation module,(ca-2.4) updating a quaternion, which is a vector representing rotation motion of said carrier, using said compensated three-axis angular increments from said angular rate compensation module, an east damping rate increment from an east damping computation module, a north damping rate increment from a north damping computation module, and vertical damping rate increment from a vertical damping computation module; and
said updated quaternion is output to a direction cosine matrix computation module,(ca-2.5) computing said direction cosine matrix, using said input updated quaternion; and
said computed direction cosine matrix is output to a level acceleration computation module and an attitude and heading angle extract module,(ca-2.6) extracting attitude and heading angle using said direction cosine matrix from said direction cosine matrix computation module;
outputting said heading angle into a vertical damping rate computation module,(ca-2.7) computing level velocity increments using said input compensated three-axis velocity increments from said acceleration compensation module and said direction cosine matrix from said direction cosine matrix computation module;
outputting said level velocity increments to an east damping rate computation module and north damping rate computation module,(ca-2.8) computing east damping rate increments using said north velocity increment of said input level velocity increments from said level acceleration computation module;
feeding back said east damping rate increments to said alignment rotation vector computation module,(ca-2.9) computing north damping rate increments using said east velocity increment of said input level velocity increments from said level acceleration computation module;
feeding back said north damping rate increments to said alignment rotation vector computation module, and(ca-2.10) computing vertical damping rate increments using said computed heading angle from said attitude and heading angel extract module and a measured heading angle from an external sensor; and
feeding back said vertical damping rate increments to said alignment rotation vector computation module.
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35. A processing method for motion measurement, as recited in claim 24, wherein the step (ca-2) further comprises the steps of:
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(ca-2.1) inputting digital three-axis angular increment values from said input/output interface circuit of the step (b) and coarse angular rate bias obtained from an angular rate producer and acceleration producer calibration procedure in high data rate for a short interval into a coning correction module;
computing coning effect errors in said coning correction module using said input digital three-axis angular increment values and coarse angular rate bias; and
outputting three-axis coning effect terms and three-axis angular increment values in reduced data rate for a long interval, which are called three-axis long-interval angular increment values, into a angular rate compensation module,(ca-2.2) inputting said coning effect errors and three-axis long-interval angular increment values from said coning correction module and angular rate device misalignment parameters and fine angular rate bias from said angular rate producer and acceleration producer calibration procedure to said angular rate compensation module;
inputting said digital temperature signals from input/output interface circuit of said step (ca-1.2) and temperature sensor scale factor;
computing current temperature of angular rate producer;
accessing angular rate producer temperature characteristic parameters using said current temperature of angular rate producer;
compensating definite errors in said input three-axis long-interval angular increment values using said input coning effect errors, angular rate device misalignment parameters, fine angular rate bias, and coning correction scale factor;
compensating temperature-induced errors in said real three-axis long-interval angular increments using said angular rate producer temperature characteristic parameters; and
outputting said real three-axis angular increments to an alignment rotation vector computation module,(ca-2.3) inputting said three-axis velocity increment values from said input/output interface circuit of said step (b) and acceleration device misalignment and acceleration bias from said angular rate producer and acceleration producer calibration procedure to acceleration compensation module;
inputting said digital temperature signals from input/output interface circuit of said step (ca-1) and temperature sensor scale factor;
computing current temperature of acceleration producer;
accessing acceleration producer temperature characteristic parameters using said current temperature of acceleration producer;
compensating said definite errors in three-axis velocity increments using said input acceleration device misalignment, acceleration bias;
compensating temperature-induced errors in said real three-axis velocity increments using said acceleration producer temperature characteristic parameters; and
outputting said compensated three-axis velocity increments to said level acceleration computation module,(ca-2.4) updating a quaternion, which is a vector representing rotation motion of said carrier, using said compensated three-axis angular increments from said angular rate compensation module, an east damping rate increment from an east damping computation module, a north damping rate increment from a north damping computation module, and vertical damping rate increment from a vertical damping computation module; and
said updated quaternion is output to a direction cosine matrix computation module,(ca-2.5) computing said direction cosine matrix, using said input updated quaternion; and
said computed direction cosine matrix is output to a level acceleration computation module and an attitude and heading angle extract module,(ca-2.6) extracting attitude and heading angle using said direction cosine matrix from said direction cosine matrix computation module;
outputting said heading angle into a vertical damping rate computation module,(ca-2.7) computing level velocity increments using said input compensated three-axis velocity increments from said acceleration compensation module and said direction cosine matrix from said direction cosine matrix computation module;
outputting said level velocity increments to an east damping rate computation module and north damping rate computation module,(ca-2.8) computing east damping rate increments using said north velocity increment of said input level velocity increments from said level acceleration computation module;
feeding back said east damping rate increments to said alignment rotation vector computation module,(ca-2.9) computing north damping rate increments using said east velocity increment of said input level velocity increments from said level acceleration computation module;
feeding back said north damping rate increments to said alignment rotation vector computation module, and(ca-2.10) computing vertical damping rate increments using said computed heading angle from said attitude and heading angel extract module and a measured heading angle from an external sensor; and
feeding back said vertical damping rate increments to said alignment rotation vector computation module.
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Specification