PNI FieldForce Trax - Manual (Page 58)

PNI Sensor Corporation DOC#1016505 r06
TRAX User Manual Page 54
methods. Note that it is possible to get acceptable scores for DistributionError
and TiltError and still have a rather high MagCalScore value. The most likely
reason for this is the TRAX is close to a source of local magnetic distortion that is
not fixed with respect to the device.
Bytes 5-8:
Reserved for PNI use.
AccelCalScore:
Represents the over-riding indicator of the quality of the accelerometer
calibration. An acceptable score is ≤1.
DistributionError:
Indicates if the distribution of sample points is good, with an emphasis on the
heading distribution. The score should be 0. Significant clumping or a lack of
sample points in a particular section can result in a poor score.
TiltError:
Indicates if the TRAX experienced sufficient tilt during the calibration, taking
into account the calibration method. The score should be 0.
TiltRange:
This reports the larger of either half the full pitch range or half the full roll range
of sample points. For example, if the device is pitched +10° to -20º, and rolled
+25º to -15º, the TiltRange value would be 20º (as derived from [+25º -
{-15º}]/2). For Full-Range Calibration and Hard-Iron-Only Calibration, this
should be ≥45°. For 2D Calibration, ideally this should be ≈2°. For Limited-Tilt
Calibration the value should be as large a possible given the user’s constraints.
7.6.4 Factory Calibration
kFactoryMagCoeff (frame ID 29
d
)
This frame clears the magnetometer calibration coefficients and loads the original
factory-generated coefficients. The frame has no payload. This frame must be
followed by the kSave frame to save the change in non-volatile memory.
kFactoryMagCoeffDone (frame ID 30
d
)
This frame is the response to kFactoryMagCoeff frame. The frame has no payload.
kFactoryAccelCoeff (frame ID 36
d
)
This frame clears the accelerometer calibration coefficients and loads the original
factory-generated coefficients. The frame has no payload. This frame must be
followed by the kSave frame to save the change in non-volatile memory.