Magnetometer calibration should be performed once Veronte has been installed on the platform so the magnetic field during the operation is similar to the one measured during the calibration. Hard calibration includes distorsions created by objetcs that produce a magnetic field (theses objetcs are the uav or their components). Soft calibration also includes the alterations in the existing magnetic field.
Magnetometer - Calibration Menu
In order to start calibration, press on the Start Calibration button so the system can capture magnetometer data. During the calibration, the system must be oriented in all possible directions so enough data can be captured. Once enough data has been captured, Compute Data sets the calibration.
The procedure for acquiring enough data for performing the calibration is:
Rotate Veronte around one of its axis (e.g. the x-axis) and make at least three turns around this axis.
Repeat the same process for another of its axis (e.g. y-axis).
Finish the calibration by repeating this process for the remaining axis (e.g. z-axis).
The different rotations that Veronte must be subjected can be visualized in the figure below.
Magnetometer - Calibration Procedure
Once three circles have been drawn on the screen, captured data will be enough for saving the calibration data. The following image shows an example of the calibration result:
Magnetometer - Calibration Values
Veronte incorporates an internal magnetometer that allows the Veronte System to measure the magnetic field.
The user can choose between 4 types of source for the accelerometer.
Integer var sensor 1-2. Veronte uses a integer value provided by a no-integrated external sensor.
Decimal var sensor 1-2. Veronte uses a decimal value provided by a no-integrated external sensor.
Internal Veronte uses the internal sensor.
External HMR2300/LIS3MDL/HSCDTD008A. Veronte uses the information from one of the compatible external magnetometers.
There are 3 parameters that are configured independently from the Magnetometer selected. These are the one in the Navigation section: - State. User can choose from Disabled for magnetometer not entering the Navigation filters (not being used but not turning it off) or Custom settings, which will take into account all the following parameters. - Square error. Means the influence of the parameter on the Navigation filters. The greater the less effect it will have. - Decimation. Defines the bunch of data from which 1 value will be stored. For example, if decimation is 10, every 10 measurements 1 will be taken into account. This procedure is used to reduce the number of samples.
Integer var sensor¶
In this menu it is possible to configure integer variables provided by an external sensor.
Integer var Magnetometer Menu - Configuration Parameters
When Integer var sensor 1 or 2 are selected, the previous panel will be shown. In this panel, the user selects the variable that has been stored in a user variable (Green Box) and the operations that will be carried on (Red Box). It is possible to use the signal through a linear or quadratic relation. The following image shows an example of a linear relation.
Linear relation of 2 Variables
The process of configuration has to be done using Custom Messages. This is to be configured in Devices - Others - Digital - I/O Manager. The configuration will depends on the device in use and its communication protocol.
Decimal var sensor¶
In this menu, the user selects real variables for each axis (X,Y,Z), these do not requiere a signal treatment. The process of configuration is similar to the one carried out when configuring a Integer Variable.
Decimal var Magnetometer Menu - Configuration Parameters
This menu available displays the posible parameters that can be configured for the internal Magnetometer.
Internal var Magnetometer Menu - Configuration Parameters
Edit Rotation Matrix brings the position of the magnetometer inside the Veronte Autopilot, it must NOT be changed under any circumstance.
In this menu it is possible to set different options regarding filters.
Digital filter. Enables a low pass filter which its cutoff frequency is configured manually, allowing the user to input any desired value in Hz. It is a software filter.
Veronte has been designed to have compatibility with the external magnetometers HMR200 and LIS3MDL. The first one has no filters configurable, only the option Edit Rotation Matrix to set the orientation of it.
The LIS3MDL option is the sensor Veronte has inside it, but mounted externally to avoid the possible interferences from being close to ekectronic components. It has de Edit Rotation Matrix and the Digital Filter.
On the other hand, the connection to the serial port is configured in Devices - Others - I/O Manager
External Magnetometer - Channel Configuration