Vega AHRS-1 / MAG-1 Operating Manual Page 9
In-Flight cali ration Procedure
Please see docu entation supplied with the SP-6 for ore infor ation.
Fly the aircraft in safe area where you can perfor rando banked turns. Do not exceed the safety li its of the aircraft
during the calibration flight.
Start the calibration in the Co pass setup enu by selecting “Calibrate”. The AHRS-1 /
MAG-1 will display the co pass calibration screen. You should see the co pass heading
change to “111” to confir that calibration has started.
Fly a nu ber of banked 180 or 360 degree turns at different bank angles - i.e. shallow, ediu and steep turns. Try to
add any different pitch attitudes in various orientations relative to the field direction. It does not atter in what order you
fly the aneuvers. A typical, good calibration tends to take 5-10 inutes of flight.
Do not activate any electrical equip ent that creates large agnetic fields during the calibration process (for exa ple
starter otors, autopilot servos, landing lights etc). The heading starts reading 111 after you start calibration. After 36
initial sa ples have been collected this changes to 222. This should take approxi ately one turn. Continue the flight
while aneuvering until the heading starts reading nor ally. This happens once the SP-6 has collected 100 distinctly
different agnetic sa ples. At this point the heading should start showing reasonable nu bers. Continue the calibration
flight, settling into straight and level at intervals on different headings and verify the heading readout against an
ACCURATE reference. Continue the flight until you find heading errors that are within 1 to 2 degrees, about the li it one
can reasonably expect.
When satisfied, end the calibration by selecting “DONE” in the co pass calibration enu. This will save the calibration to
per anent e ory in the SP-6. Should you not be able to achieve a good heading readout, please locate the co pass to
a better location in the aircraft.
The AHRS-1 / MAG-1 displays the calibration sa ple count and fit percentage during calibration. The sa ple count will
count up to 150 after which new sa ples replace the oldest sa ples stored. The fit percentage is a value fro 0% to
100%. The ai is to get to a value as close as possible to 100%. The fit starts displaying other than 0% after the first 36
sa ples. Fit values of 98% and higher are considered good. If you cannot achieve this you do not have a good
installation location for your co pass. You ay still get reasonably good heading accuracy despite a lower fit. However,
to ensure long ter accuracy please consider locating the SP-6 in a better area in your aircraft.
If the readout decreases suddenly by a large a ount (for exa ple fro 85% to 42%), this is typically caused by a
strong ti e-variant agnetic field such as can be created by electrical equip ent ( otors, relays, current flow in cables).
In such a case please either end and restart the calibration or continue the calibration flight until the fit error is acceptable
again (the incorrect agnetic sa ple(s) will eventually be re oved). It is advised to locate the interference source and
either ove this or the SP-6 to a better location in the aircraft.
Note: should you ove the SP-6 to a new location or fit new equip ent close to the SP-6 you will have to perfor the
calibration again. There is no practical li it as to how any ti es you can perfor and save a new calibration.
