A5023/24
3 of 19
1. Introduction and description of fluxgate compass.
1.1 Description of compass.
The Autonnic NMEA compass unit is a complete component for a compass
indicating system, RADAR ‘North
-
up’ input or autopilot. It is housed in a
water-resistant enclosure so it can be mounted outside a steel hull. It
delivers heading data in two industry-standard forms.
The A5023 and A5024 contain a fluxgate with floating core surrounded by
high-precision interface circuits which, together with the special
clockwise/anticlockwise and offset nulling sequence allow a
microprocessor to acquire a binary value from two orthogonal sensors of
the
horizontal component of the Earth’s magnetic field. The processor
calculates the vector from these values, uses a calibration table to correct
for local field disturbance errors, offsets the result and then presents the
data in a manner which has been requested. Such requests alter the
frequency of the data, the degree of filtering and the offset value.
Calibration sequences can also be commanded.
