Integrated-strapdown-air-data sensor system
First Claim
1. An integrated-strapdown-air-data sensor system for an aircraft comprising:
- (a) a plurality of inertial measuring unit (IMU) modules, suitable for strapdown mounting in an aircraft, each of said IMU modules acceleration of said aircraft along at least two different axes and producing raw angular rate and raw linear acceleration signals related thereto, each of said IMU modules including a temperature sensor for sensing the temperature of the related IMU module and producing an IMU temperature signal related thereto;
(b) at least one pressure transducer module, suitable for mounting in an aircraft, for sensing air data and producing raw air data signals related thereto;
(c) at least one total air temperature sensor, suitable for mounting in an aircraft, for sensing the outside total air temperature at the skin of the aircraft and producing a total air temperature signal related thereto; and
,(d) at least one signal processor coupled to said plurality of IMU modules, said at least one pressure transducer module and said at least one total air temperature sensor, for;
(1) receiving said raw angular rate, raw linear acceleration, IMU temperature, raw air data and total air temperature signals;
(2) converting said raw angular rate, raw linear acceleration, IMU temperature, raw air data, and total air temperature signals into common time base digital form;
(3) compensating said raw angular rate and raw linear acceleration signals in common time base digital form for various types of errors that cause said raw angular rate and raw linear acceleration signals to be inaccurate and producing accurate body angular rate and accurate body linear acceleration signals;
(4) calibrating said raw air data signals in common time base digital form to produce accurate air data signals; and
,(5) combining said accurate body angular rate and accurate body acceleration signals, and said accurate air data signals, to produce accurate attitude, navigational position and velocity signals that define the attitude, navigational position and velocity of said aircraft and are suitable for use by the automatic flight control, navigation and display systems of said aircraft.
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Accused Products
Abstract
A plurality of inertial measuring unit (IMU) modules (41A, B, C and D) each comprising gyros and accelerometers (61, 65 and 67) for sensing inertial information along two orthogonal axes, are strapdown mounted in an aircraft, preferably such that the sense axes of the IMUs are skewed with respect to one another. Inertial and temperature signals produced by the IMU modules, plus pressure signals produced by a plurality of pressure transducer modules (43A, B and C) and air temperature signals produced by total air temperature sensors (45A and B) are applied to redundant signal processors (47A, B and C). The signal processors convert the raw analog information signals into digital form, error compensate the incoming raw digital data and, then, manipulate the compensated digital data to produce signals suitable for use by the automatic flight control, pilot display and navigation systems of the aircraft. The signal processors include: an interface system comprising a gyro subsystem (47), an accelerometer and air calibration data subsystem (50) and an air data and temperature subsystem (52); a computer (54); an instruction decoder ( 56); and, a clock (58). During computer interrupt intervals raw digital data is fed to the computer (54) by the interface subsystems under the control of the instruction decoder (56). The computer includes a central processing unit that compensates raw digital gyro and accelerometer data to eliminate bias, scale factor, dynamic and temperature errors, as necessary. The central processing unit also modifies the gyro and accelerometer data to compensate for relative misalignment between the sense axes of the gyros and accelerometers and for the skewed orientation of these sense axes relative to the yaw, roll and pitch axes of the aircraft. Further, accelerometer data is transformed from body coordinate form to navigational coordinate form and the result used to determine the velocity and position of the aircraft. Finally, the central processing unit develops initializing alignment signals and develops altitude, speed and corrected temperature and pressure signals.
275 Citations
62 Claims
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1. An integrated-strapdown-air-data sensor system for an aircraft comprising:
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(a) a plurality of inertial measuring unit (IMU) modules, suitable for strapdown mounting in an aircraft, each of said IMU modules acceleration of said aircraft along at least two different axes and producing raw angular rate and raw linear acceleration signals related thereto, each of said IMU modules including a temperature sensor for sensing the temperature of the related IMU module and producing an IMU temperature signal related thereto; (b) at least one pressure transducer module, suitable for mounting in an aircraft, for sensing air data and producing raw air data signals related thereto; (c) at least one total air temperature sensor, suitable for mounting in an aircraft, for sensing the outside total air temperature at the skin of the aircraft and producing a total air temperature signal related thereto; and
,(d) at least one signal processor coupled to said plurality of IMU modules, said at least one pressure transducer module and said at least one total air temperature sensor, for; (1) receiving said raw angular rate, raw linear acceleration, IMU temperature, raw air data and total air temperature signals; (2) converting said raw angular rate, raw linear acceleration, IMU temperature, raw air data, and total air temperature signals into common time base digital form; (3) compensating said raw angular rate and raw linear acceleration signals in common time base digital form for various types of errors that cause said raw angular rate and raw linear acceleration signals to be inaccurate and producing accurate body angular rate and accurate body linear acceleration signals; (4) calibrating said raw air data signals in common time base digital form to produce accurate air data signals; and
,(5) combining said accurate body angular rate and accurate body acceleration signals, and said accurate air data signals, to produce accurate attitude, navigational position and velocity signals that define the attitude, navigational position and velocity of said aircraft and are suitable for use by the automatic flight control, navigation and display systems of said aircraft. - 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, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. A strapdown inertial sensing system suitable for use in an aircraft to produce signals representing the attitude, position and velocity of the aircraft, said strapdown inertial sensing system comprising:
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(a) a plurality of inertial measuring unit (IMU) modules, suitable for strapdown mounting in an aircraft, each of said plurality of IMU modules including inertial sensing means for sensing the angular rate and the linear acceleration of said aircraft along at least two different axes and producing raw angular rate and raw linear acceleration signals related thereto, each of said IMU modules including a temperature sensor for sensing the temperature of the related IMU module and producing an IMU temperature signal related thereto; and
,(b) at least one signal processor coupled to said plurality of IMU modules for; (1) receiving said raw angular rate, raw linear acceleration and IMU temperature signals; (2) converting said raw angular rate, raw linear acceleration and IMU temperature signals into common time base digital form; (3) compensating said raw angular rate and raw linear acceleration signals in common time base digital form for various types of errors that cause said raw angular rate and raw linear acceleration signals to be inaccurate and producing accurate body angular rate and accurate body linear acceleration signals; (4) combining said accurate body angular rate and accurate body linear acceleration signals with an altitude signal to produce accurate signals representing the attitude, position and velocity of an aircraft incorporating said strapdown inertial sensing system. - View Dependent Claims (43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62)
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Specification