Honeywell's magnetoresistive (MR) sensors are the most sensitive, low field, solid state magnetic sensors available to measure direction and magnitude of magnetic fields from 70 mG (7 nT) to 6 G (0.6 mT). Honeywell's magnetoresistor sensors can determine the change in earth's magnetic field due to the presence of a ferromagnetic object or position within the earth's magnetic field. The high bandwidth allows detection of vehicles and other ferrous objects at high speeds. The sensors are contactless and the working distance is dependent on the ferromagnetic mass it is measuring.
This means that the devices are suitable for many applications other than simple compassing, such as platform levelling or proximity detection for example.