Jackson Labs Mini-JLT GNSS, Руководство пользователя

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Mini-JLT GNSS™
User Manual
GPS:GYRO <int> [0,255]
GPS:GYRO? returns the setting of the period of this command.
The output of the system is in six floating point numbers: the acceleration on the X, Y, and Z axis in
g’s, and the Tilt of the X, Y, and Z axis in Degrees (-90 to +90).
Please note that the Accelerometer has its best resolution and accuracy when the earth’s gravitational
acceleration is perpendicular to the axis to be measured. Thus the sensors accuracy and resolution
will be best when the tilt of any axis is around 0 Degrees. The worst performance (with an accuracy
of only ~ +/-5 Degrees) is when any of the axis are at their +/- 90 Degree angles, this is due to the fact
that a SIN(g-load) calculation is done to generate the output normalized to Degrees, and the vector is
thus least sensitive at +/- 90 Degree angles.
Acceleration can be measured with up to +/-3g range on all three axis. Please note that since the tilt
angle is calculated from the acceleration vectors (using gravity) that the tilt angles will actually
/-90 Degrees when acceleration greater than 1g is applied.
3.3.13 GPS:GYRO:CAL
This command calibrates the output period of the Accelerometer data (in g’s per axis, and in tilt in
Degrees per axis). Both offset and gain need to be calibrated on the unit to properly format the output
of the three axis tilt to be -90 Degrees to +90 Degrees, and the 0 Degree reference.
By default, the unit is shipped with a normalized output of 0 Degrees Offset, and a gain of 1.0, and
the user will need to calibrate their unit in their system.
This command has the following format:
GPS:GYRO:CAL <float>, <float>, <float>, <float>, <float>, <float>
Calibration is accomplished by slowly tilting the unit on all six axis and measuring the maximum and
minimum tilt indications in all six axis, and writing these down on a piece of paper to calculate the
calibration values. Later firmware releases may automate this process.
Example: if the result for say the X axis is -87 Degrees to +93 Degrees, then we need to remove an
offset of +3 Degrees from the X axis while the gain of the X axis is properly set. We would thus send
the following calibration command to the unit:
GPS:GYRO:CAL -3, 0, 0, 1, 1, 1
This will remove a 3 Degree offset from the X Axis, and keep the Y and Z axis without offset or gain
adjustments.