Power to Win

KB1040 -Using GPS Data


The QD2 logger can be configured to accept serial data from an external GPS device. This feature adds several new channels of data to the logger channel list. The interface is only compatible with the EFI GPS assy, part number 61-607. This unit is a 5Hz GPS receiver that sends serial data at 9600 bps continuously to the logger.

The user can select the GPS Input to be used for System Speed which is also used to calculate the distance channel. This feature provides accurate speed data, eliminates errors caused by wheel lockup and negates the need for any wheel sensors to calculate the speed of the vehicle.

Track Mapping

To draw a track map from GPS data you must log both the Latitude and Longitude data channels. You must also have at least 2 beacons in the data to identify the in and out laps which should not be used to draw a track map. In the create track map window be sure to check the GPS Data option to tell analysis to use the GPS data instead of Lateral G data for mapping.

GPS Channels

ID Description Units Comments
256 Speed mph
260 Version bits bits 0-2 report the solution type
263 Time of Week millisec
264 Longitude degs geodetic data
265 Latitude degs geodetic data
266 Altitude feet geodetic data
267 Heading deg degs clockwise from true north
268 X Velocity mtrs/sec
269 Y Velocity mtrs/sec
270 Z Velocity mtrs/sec
271 V Acceleration mtrs/sec climb rate
272 X Position mtrs ECEF data
273 Y Position mtrs ECEF data
274 Z Position mtrs ECEF data

Geodetic Data

In the geodetic coordinate system the Earth's surface is approximated by an ellipsoid and the locations near the surface are described in terms of latitude, longitude and altitude. The ellipsoid is completely parameterised by the semi-major axis and its flattening. These systems are needed because the earth is not a perfect sphere.


The ECEF channels are the cartesian GPS coordinates, called Earth-Centered Earth-Fixed. The ECEF uses 3 dimensional XYZ coordinates to describe the location of the GPS user or satellite. The term Earth-Centered comes from the fact that the origin of the axis (0,0,0) is located at the mass center of gravity. The term Earth-Fixed implies that the axes are fixed with respect to the earth (that is, they rotate with the earth). The Z-axis pierces the North Pole, and the XY-axis defines the equatorial plane.


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