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US 7,458,264 B2Granted
Generalized inertial measurement error reduction through multiple axis rotation during flight
AssigneeHoneywell International Inc.
InventorRobert H. Fall
Life of this patent
Estimating the term…
Abstract
An inertial measurement unit is provided. The inertial measurement unit comprises two rotational axes, wherein a first of the two rotational axes is aligned nominally along a thrust axis and a second of the two rotational axes is aligned substantially perpendicular to a plane formed by a local gravity vector and a thrust vector, and one or more sensors which rotate about the second rotational axis.
Claims25
An inertial measurement unit comprising:
- a first gimbal adapted to be aligned nominally along a thrust axis;
- a second gimbal, located within said first gimbal and adapted to be rotated about an axis substantially perpendicular to a plane of trajectory;
- wherein said plane of trajectory is formed by a local gravity vector and a thrust vector along said thrust axis;
- one or more sensors coupled to said second gimbal and adapted to sense acceleration along said thrust axis;
- and
- wherein the second gimbal rotates the one or more sensors when the inertial measurement unit is accelerating along the thrust axis to modulate thrust accelerations and gravity accelerations sensed by the one or more sensors.
3 more elements
A method of reducing sensor errors in an inertial guidance system, the method comprising:
- aligning a first rotational axis nominally along a thrust axis;
- maintaining the alignment of a second rotational axis substantially orthogonal to a plane of trajectory formed by a local gravity vector and a thrust vector along said thrust axis;
- and
- rotating one or more accelerometers about an axis substantially perpendicular to the plane of trajectory to modulate thrust accelerations and gravity accelerations sensed by the one or more sensors.
1 more element
An inertial measurement unit comprising:
- two rotational axes, wherein a first of the two rotational axes is aligned nominally along a thrust axis and a second of the two rotational axes is aligned substantially perpendicular to a plane formed by a local gravity vector and a thrust vector;
- and
- three or more sensors, two sensors of which rotate about the second rotational axis to modulate thrust accelerations and gravity accelerations sensed by the two sensors.
An inertial measurement unit comprising:
- a sphere having at least a first rotational axis and a second rotational axis, wherein the first rotational axis is nominally aligned along a thrust axis, and wherein the second rotational axis is maintained perpendicular to a plane of trajectory formed by a local gravity vector and a thrust vector along said thrust axis;
- and
- at least three accelerometers mounted within the sphere, wherein at least two accelerometers are aligned to sense acceleration along the thrust axis;
- and
- wherein the sphere is rotated about the second axis to modulate thrust accelerations and gravity accelerations sensed by the at least two sensors.
2 more elements
Dependencies are inferred from the claim text.