Inertial Aerosystems has announced a miniature electronic board module that provides the user's position relative to a preselected point. Manufactured by US-based Honeywell, the Dead Reckoning Module (DRM) 4000 gives an accurate position derived from dead reckoning data and external GPS NMEA data disciplined by an internal Kalman filter.
+++ STOP PRESS 2 November 2011 - This product has been superseded by the DRM4000L dead reckoning module, which is also available from ETLG Inertial Aerosystems, so contact the company for more information about this upgraded module. +++
The DRM4000 can operate accurately with intermittent GPS signals. When GPS data is available the dead reckoning sensors are calibrated continuously and the two data sources are then blended into a composite real-time position data output. If GPS data is unavailable dead reckoning takes over. In dead reckoning mode, position accuracy of 2 per cent of distance travelled is achievable.
Patented motion classification algorithms analyse walking motion, and compensate when the user is running or in semi-static mode. Automatic compass orientation algorithms provide accurate azimuth information when the user is upright or prone. Gyros are incorporated to compensate for magnetic transients and accelerations that could interfere with compass operation. A barometric altimeter provides vertical position accurate to 1.5m for discrimination between floors of a building.
This versatile device weighs only 25g and measures 50.8 x 50.8 x 12.7mm, so it is suitable for mounting on the user's torso, with no additional sensors required. Power consumption is less than 0.5W at 2.8-5.2V DC power. Sensors include three gyros, three accelerometers and three magnetometers; the unit operates accurately within a temperature range of -40 to +85 degrees C.
A typical application would be tracking of emergency service personnel, but the DRM 4000 also has uses in the engineering, manufacturing and processing industries.