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Chapter 3
3.1
Data and File Formats
Data Formats
In theory, virtually any IMU sensor can be used with
Inertial Explorer. The only requirement is that the data
be logged in the format provided below, which allows
easy decoding with IMU Data Conversion utility
described in Section 2.1.1, on Page 49 .
The Table 2, in the shaded box, presents the binary
structure in which the conversion utility expects the
raw IMU data to be logged.
Please contact Customer Service if you are
unable to log data into the specified format.
3.1.1
NovAtel’s SPAN Technology
With the use of NovAtel’s SPAN technology, note the
difference in the IMU data decoding procedure. Since
the raw IMU data measurements are embedded into
the same binary file containing the raw GNSS
measurements, only one step will be needed to
separate the data and convert it into the Waypoint
Group’s format so the Raw IMU Data Converter
utility does not need to be used.
Table 2: Binary Structure of Raw Data
Size
(bytes)
Word
Type
Description
GpsTime
8
real
time of the current IMU rate
measurements in GPS
seconds of the week.
GyroX
4
long
scaled X-body axis gyro
measurement as anangular
increment or angular rate
GyroY
4
long
scaled Y-body axis gyro
measurement as anangular
increment or angular rate
GyroZ
4
long
scaled Z-body axis gyro
measurement as anangular
increment or angular rate
AccelX
4
long
scaled X-body axis accel
measurement as a velocity
increment or acceleration
AccelY
4
long
scaled Y-body axis accel
measurement as a velocity
increment or acceleration
AccelZ
4
long
scaled Z-body axis accel
measurement as a velocity
increment or acceleration
Instead, decode the GNSS and IMU data
simultaneously via the Convert Raw GNSS data to
GPB utility, which can be accessed via File | Convert.
When adding the measurement file to the Convert
Files window for decoding, ensure that the drop-down
menu under the Receiver Type box has been set to
NovAtel OEM4. Then, click either the Global Options
or Options button to gain access to the IMU decoding
settings.
AG11 = AG58
AG17 = AG62
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Inertial Explorer 8.20 User Guide Rev 6