Apparatus and method for measuring specific force and angular rate
First Claim
1. Apparatus for measuring the specific force and angular rate of a moving body by means of a plurality of accelerometers mounted on mutually-perpendicular axes, characterized in that the apparatus includes:
- (a) cyclic driving means for driving each accelerometer at a predetermined cyclic frequency "ω
" to produce an output signal "a" from each accelerometer comprised of the angular rate vector "Ω
" and the specific force vector "F;
"(b) means for deriving, from each of said accelerometer output signals "a," a signal corresponding to the angular rate vector "Ω
" which means includes;
(1) multiplying means for multiplying said accelerometer output signal "a" by the function "sgn cos ω
t" to produce the product signal "asgn cos ω
t," and(2) integrating means for integrating said product signal over the cyclic period; and
(c) means for deriving from each of said accelerometer output signals "a" a signal corresponding to the specific force vector "F," said latter means including integrating means for integrating said output signal "a" over the cyclic period.
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Abstract
Apparatus and method for measuring specific force and angular rate of a moving body, particularly useful for a non-gyroscopic inertial measuring unit, comprises an orthogonal triad of rotating accelerometers, each producing an output signal "a", from which output signals are derived both (1) the angular rate vector Ω by multiplying the accelerometer output signal "a" by the function "SgnCosωt" and integrating the resulting product over the cyclic period, and (2) the specific force vector F, by integrating the output signal "a" over the cyclic period, this processing of the accelerometer output signals substantially suppressing the unwanted components of these signals.
73 Citations
19 Claims
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1. Apparatus for measuring the specific force and angular rate of a moving body by means of a plurality of accelerometers mounted on mutually-perpendicular axes, characterized in that the apparatus includes:
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(a) cyclic driving means for driving each accelerometer at a predetermined cyclic frequency "ω
" to produce an output signal "a" from each accelerometer comprised of the angular rate vector "Ω
" and the specific force vector "F;
"(b) means for deriving, from each of said accelerometer output signals "a," a signal corresponding to the angular rate vector "Ω
" which means includes;(1) multiplying means for multiplying said accelerometer output signal "a" by the function "sgn cos ω
t" to produce the product signal "asgn cos ω
t," and(2) integrating means for integrating said product signal over the cyclic period; and (c) means for deriving from each of said accelerometer output signals "a" a signal corresponding to the specific force vector "F," said latter means including integrating means for integrating said output signal "a" over the cyclic period. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. Apparatus for measuring the specific force and angular rate of a moving body by means of an accelerometer, characterized in that the apparatus includes:
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(a) cyclic driving means for driving said accelerometer at a predetermined cyclic frequency "ω
" to produce an output signal "a" comprised of the angular rate vector "Ω
" and the specific force vector "F;
"(b) means for deriving, from said accelerometer output signal "a," a signal corresponding to the angular rate vector "Ω
," including;(1) multiplying means for multiplying said accelerometer output signal "a" by the function "sgn cos ω
t" to produce the product signal "asgn cos ω
t," and(2) integrating means for integrating said product signal over the cyclic period; and (c) means for deriving from said accelerometer output signal "a" a signal corresponding to the specific force vector "F," said latter means including integrating means for integrating said output signal "a" over the cyclic period.
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9. Apparatus for measuring the specific force of a moving body by means of an accelerometer, characterized in that the apparatus includes:
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(a) cyclic driving means for driving said accelerometer at a predetermined cyclic frequency "ω
" to produce an output signal "a;
" and(b) means for deriving, from said accelerometer output signal "a," a signal corresponding to the angular rate vector "Ω
", including;(1) multiplying means for multiplying said acceleration output signal "a" by the function "sgn cos ω
t" to produce the product signal "asgn cos ω
t", and(2) integrating means for integrating said product signal over the cyclic period. - View Dependent Claims (10, 11)
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12. A processor for deriving, from an accelerator output signal "a" produced by cyclically driving the accelerometer at a predetermined cyclic frequency "ω
- " a first signal corresponding to the annular rate vector "Ω
" component of the accelerator output "a," and a second signal corresponding to the specific force vector component "F" of the accelerator output signal "a," comprising;means for multiplying said accelerator output signal "a" by the function "sgn cos ω
t" to produce the product signal "asgn cos ω
t;
"first integrating means for integrating said latter product signal over the cyclic period, to produce a signal corresponding to the annular rate vector "Ω
"; andsecond integrating means for integrating said accelerometer output signal "a" over the cyclic period, to produce a signal corresponding to the specific force vector "F". - View Dependent Claims (13, 14)
- " a first signal corresponding to the annular rate vector "Ω
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15. A method of measuring the specific force and angular rate of a moving body by means of a plurality of accelerometers mounted on mutually-perpendicular axes, characterized by the steps:
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(a) cyclicly driving each accelerometer at a predetermined cyclic frequency "ω
" to produce an output signal "a" from each accelerometer comprised of the angular rate vector "Ω
" and the specific force vector "F";(b) deriving from each of said acceleromoter output signals "a," a signal corresponding to the annular rate vector "Ω
" by;(1) multiplying said acceleration output signals "a" by the function "sgn cos ω
t" to produce the product signal "asgno cos ω
t", and(2) integrating said product signal over the cyclic period; and (c) deriving from each of said accelerometer output signals "a", a signal corresponding to the specific force vector "F", by integrating said output signal "a" over the cyclic period. - View Dependent Claims (16, 17, 18)
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19. A method for deriving from an accelerometer output signal "a," produced by cyclically driving the accelerometer at a predetermined cyclic frequency "ω
- " a first signal corresponding to the angular rate vector "Ω
" component of the accelerator output "a", and a second signal corresponding to the specific force vector "F" component of the accelerator output signal "a," comprising;multiplying said accelerator output signal "a" by the function "sgn cos ω
t" to produce the product signal "asgn cos ω
t";integrating said latter product signal over the cyclic period to produce a signal corresponding to the annular rate vector "Ω
"; andintegrating said accelerometer output signal "a" over the cyclic period, to produce a signal corresponding to the specific force vector "F".
- " a first signal corresponding to the angular rate vector "Ω
Specification