Triggered NMEA messages

Software Releases

August 3, 2010

135_cameraWouldn’t it be easy if you could get an NMEA message that corresponded to the exact time that a photo was taken? Now you can. The Inertial+ can accurately capture the shutter closure of a camera using its event input. The firmware in the Inertial+ then generates an NMEA message, interpolated to the exact time that the camera image was taken. This message can be output on the serial port and later matched to each image. Geo-referencing made easy.

By using the GGA message (with position) and the PASHR message (with heading, pitch and roll) the position and orientation of the photo, at the time it was taken, can be logged into one file with ease. By performing the interpolation in the Inertial+, a lot of mathematics in the external software can be avoided and a lot less data needs to be stored.

The compact Inertial+ system also has a camera trigger output, which can be used by some cameras to take a photo. The inertial navigation system can be configured to take a photo every 10m, or at some other spacing. The result is a series of photos along the driven route, all with geo-referencing information, and without the need for the driver to be involved.

These triggered measurements are also available on the Ethernet output using special NCOM packets. The event input has been available for some time but now the camera output trigger has also been added to the Ethernet output.

For people using post-processing, the external events are stored in the internal file of the Inertial+ and can be output using the post-processing software to a CSV file.

For more information on how the event inputs and camera trigger outputs work, please see the Inertial+ user manual or contact support at OxTS.