The G60, G100, and Dart support accelerometer-based harsh driving and accident detection. In contrast to many competing solutions, these devices do not require any special orientation or calibration procedure during installation.
Simply secure the device firmly to the vehicle chassis, in any location that will not see excessive vibration, and at any convenient angle. The unit should not rattle or change orientation during driving, so try to avoid cable ties to flimsy wiring harnesses, and installs that might impact nearby objects when vibrating.
Once power is applied, the unit will begin to continuously self-calibrate. It begins from an uncalibrated state, in which the harsh driving detection is disabled, and the accident detection is in a basic mode that ignores orientation. Once the vehicle begins a trip, each time it accelerates, brakes, or turns, the unit can compare the acceleration to the GPS velocity to determine its orientation. Each maneuver increases the accuracy of the orientation, and when the accuracy is high enough, harsh driving and advanced accident detection are enabled. This typically takes 10 to 15 minutes of driving.
Even after the initial settling period, the unit continues to self-calibrate, so it will adjust to small changes in position. Large changes will result in a few minutes of inaccurate data (~90 minutes if the direction of 'down' has changed), while it adjusts to the new conditions. When intentionally re-orienting the unit, you can reset it to its uncalibrated state by flipping it over for a few seconds. In addition to triggering an accident event for the rollover (if configured), this resets all orientation data, disabling the harsh driving and advanced accident detection until recalibration is complete. The unit will recalibrate faster if you reset it in this way.