PitLab Autopilot User Manual page 16

Autopilot – User's manual
time in the direction of the base flies in an arc and at the end of the flight
is always hitting the base against the wind. In this case, the distance
traveled by the model is longer than the optimum. The advantage of
magnetic heading is also that, regardless of whether the model is moving
forward or in a strong wind gusts moves back it is always directed
towards the base.
Figure 17 flight in strong winds according to magnetic course
NOTE: The magnetic field sensor (electronic compass) is sensitive to any
kind of disturbance of the magnetic field caused by the presence of the
magnets (e.g. magnetic latches of cabin, neodymium magnets inside
motor), the magnetic fields generated by flowing current (power cables
to the motor) and metal (magnetic) objects near the sensor, such as
plates, brackets, bayonets, etc. Therefore, you should check if the
directions indicated by the electronic compass of the Autopilot coincide
with the actual geographic directions.
© Pit Lab 2017 https://www.pitlab.com/fpv-system/autopilot.html
Choosing GPS or barometric altimeter
Autopilot allows you to select the type of altimeter, which is used to
maintain altitude in AUTO mode and indicates the altitude of on-screen
display.
Barometric altimeter is recommended for most flights. It provides high
precision of determining the altitude and its change, which can provide
information about the speed of descent or ascent of the model
(variometer) with accuracy of 0.1 - 0.2 m / s, but it is sensitive to changes
in atmospheric pressure, so during the flight and after landing the
altitude indicated by the altimeter can change within a few meters in
comparison to the initial value.
GPS altimeter is insensitive to weather conditions and provides a small
percentage error at high altitudes, however, poses a significant absolute
error of indications and its height can change unexpectedly and jump up
and down even in tenth of meters. Therefore, when using altitude from
GPS the variometer that indicates the rate of ascent / descent is not
available. GPS altitude can be used in high or prolonged flights in
changeable weather conditions.
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