Triggered NMEA outputs in RT

Software Releases

December 8, 2010

Some of our customers are using the RT in combination with one or more cameras on a survey vehicle. The latest software update now introduces triggered NMEA outputs for all OxTS RT inertial and GPS systems. This means you can now get an NMEA message that corresponds to the exact time that a photo was taken. The RT can accurately capture the shutter closure of a camera using its event input. The firmware in the RT 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.

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 RT, a lot of mathematics in the external software can be avoided and a lot less data needs to be stored.

The RT system also has a camera trigger output, which is invaluable for taking photos at regular distances, for example every 10m. The output includes measurements of position and orientation which are essential for accurately geo-referencing the images.

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

For more information please contact support at OxTS.