Magnetometer Board.

1. The GPS receiver is seen on the top far left of the board
2. The DC/DC converter and regulators are on the bottom far left
3. The single chip controller
4. The precision ADC and low pass filters are under the shield near the center of the board.
5. The Magnetometer drive/sense circuits occupy the right half of the board.

Magnetometer Sensor.

The detail manufacturing drawings for the ground based magnetometer sensor. This sensor is designed to be installed in a post hole about 3 feet below the surface to minimize temperature effects. It includes internal heaters which can be used to further stabilize the temperature. This assembly includes:

1. A three axis sensor assembly
2. Heaters, thermistors, and oil filled container for temperature stabilization.
3. The 1M tube and insulation and is attached to a 30M cable.

Major Components.

A black/white copy of the magnetometer board with a typical three axis sensor assembly. This illustrates the major components in a typical fluxgate system.

1. Typical sensor assembly includes:
   • Three axis sensor fixture
   • Single axis sensor bobbin
   • Single axis drive core with windings
   • Drive core without windings
2. Ground based Magnetometer electronics using surface mount technology.