Mechanical shock resistant MEMS accelerometer arrangement, associated method, apparatus and system

摘要

An accelerometer arrangement and method are described for determining accelerations of an inground tool. First and second triaxial accelerometers are supported such that a normal sensing axis of the first triaxial accelerometer is at least generally orthogonal to the normal sensing axis of the second triaxial accelerometer for determining the accelerations along the three orthogonal axes based on a combination of sensing axis outputs from one or both of the triaxial accelerometers. A weaker sensing axis of one triaxial accelerometer can be supported at least approximately normal to a weaker sensing axis of another triaxial accelerometer such that the weaker axes are not used. The triaxial accelerometers can be supported such that one axis of one accelerometer can be redundant with respect to another axis of another accelerometer. One triaxial accelerometer can be mounted on a tilted plane with respect to another triaxial accelerometer.

主权项

1. An accelerometer arrangement configured to determine accelerations of an inground tool along three orthogonal axes during an inground operation that exposes the accelerometer arrangement to a mechanical shock and vibration environment, said accelerometer arrangement comprising:
a first MEMS triaxial accelerometer and a second MEMS triaxial accelerometer, each of which includes a set of three orthogonally arranged accelerometer sensing axes including a pair of in-plane sensing axes and a normal sensing axis such that the normal sensing axis is subject to a higher rate of failure responsive to mechanical shock and vibration than the in-plane sensing axes; a support structure configured to support the first and second triaxial accelerometers such that the normal sensing axis of the first triaxial accelerometer is at least generally orthogonal to the normal sensing axis of the second triaxial accelerometer; and a processor configured to determine the accelerations along said three orthogonal axes based on a combination of sensing axis outputs from the first and second triaxial accelerometers without using normal sensing axis outputs of each of the first and second triaxial accelerometers.