Mems gyroscope magnetic sensitivity reduction

A tuning fork gyroscope that is insensitive to magnetic field gradients, the tuning fork gyroscope comprising:

• means to suspend a first conductive proof mass and a second conductive proof mass over at least one insulating substrate;
• means to couple the first conductive proof mass and the second conductive proof mass to AC ground;
• and
• means to generate an output signal indicative of the tuning fork resonant mode, the means to generate being operable to receive an input from an electrical-resistance mid-point of the means to suspend, wherein the generated output signal is unaffected when the first conductive proof mass and the second conductive proof are subjected to a magnetic field gradient.

A magnetic gradiometer comprising:

• a first electrically conducting proof mass connected through electrically conducting suspensions to anchors attached to one or more insulating substrates;
• a second electrically conducting proof mass connected through electrically conducting suspensions to the anchors attached to the one or more insulating substrates, wherein the first electrically conducting proof mass and the second electrically conducting proof mass are capacitively coupled to DC ground and are driven to move in an oscillatory motion with opposing velocities along a motor axis;
• and
• a sense charge amplifier configured to receive a first input from one of the anchors and to receive a second input from DC ground, wherein the sense charge amplifier generates an output signal indicative of a magnetic field gradient to which the first electrically conducting proof mass and the second electrically conducting proof mass are exposed.

A magnetic gradiometer comprising:

• a first electrically conducting proof mass and a second electrically conducting proof mass driven to move in an oscillatory motion with opposing velocities along a motor axis;
• a first end of the first electrically conducting proof mass connected through electrically conducting suspensions to a first anchor attached to an insulating substrate;
• a first end of the second electrically conducting proof mass connected through electrically conducting suspensions to the first anchor;
• a second end of the first electrically conducting proof mass connected through electrically conducting suspensions to a second anchor attached to the insulating substrate;
• a second end of the second electrically conducting proof mass connected through electrically conducting suspensions to the second anchor;
• and
• a readout amplifier configured to receive a first input from the first anchor and to receive a second input from the second anchor, wherein the sense charge amplifier generates an output signal indicative of a magnetic field gradient to which the first electrically conducting proof mass and the second electrically conducting proof mass are exposed.