iLevil 3 AW Company Standards
Effective Date
12/22/17
Page
7
of
10
Document No.
46
Revision
1
Code Number
D-0010
9.1
AD-AHRS
The AHRS Micro is an electronic device developed by Levil Aviation which consists of
sensors on three axes that provide attitude and heading information and air data for an
aircraft. It is designed and manufactured by Levil Aviation, guaranteeing each individual
board is calibrated to withstand extreme environmental conditions (turbulence, humidity,
high-temperatures, etc.) The AHRS information is sent by the IMU Microprocessor to the
ILEVIL 3 AW’s main Microprocessor which is then transmitted to a tablet via Wi-Fi and
displayed accordingly. Because of the AHRS component, the ILEVIL 3 AW must be aligned
during installation to display accurate Attitude with respect to the aircraft’s straight and level
flight. The following listed performance requirements must be met by the AHRS system:
9.1.1
Temperature Calibration
AHRS are individually calibrated in a wide range of temperatures so that their performance is
not affected by extreme temperatures during flight. The calibration process ranges from -
10°C to 80°C. Temperature matrixes are computed, and a plot of the temperature behavior of
the gyros and accelerometers is analyzed for linearity. Figure xxx. Shows an example of a
temperature calibration plot; each color represents a gyro or accelerometer.
Figure 2. Temperature Calibration plot example
9.1.2
Magnetic Heading
The AHRS uses a 3-axis magnetometer to calculate magnetic heading (even when airplane is
up-side-down). The magnetometer is calibrated individually using a Helmholtz Coil.
Magnetic readings are taken, values analyzed for accuracy and matrixes computed and sent
to the IMU microprocessor. The Magnetic heading is tested for accuracy after calibration. An
AHRS compass is considered to Fail if the compass is off by ±10° from the true value.