Suitable Collision Types and Pre-crash Motions
The GST is suitable for replicating a wide range of collision types where the use of human-driven vehicles (or vehicles towing soft targets) would be unrealistic, problematic or hazardous and where precise time-space control and coordination of two vehicles is required, including the following conflict and potential collision types:

• Rear-end
• Crossing path
• Head-on
• Side-swipe
• Pedestrian (using an auxiliary, small trolley with inflatable pedestrian figure)

Additionally, the GST provides a high degree of flexibility in test scenario setup.  The path and speed profile of the GST can be derived from physics-based reconstructions, or hypothetical scenarios, allowing the GST to follow straight, curved or complicated paths with a varying speed profile.  This allows the test engineer to create complex subject vehicle and collision partner interactions in order to thoroughly evaluate the system under test.

Method of Operation

The system operates using paired time-space trajectories (one trajectory each for the subject vehicle and GST) which are loaded into the on-board GST processor memory.  The positions of the subject vehicle and GST are measured continuously using differential GPS.  The subject vehicle position is broadcast via a wireless LAN to the GST, which compares the measured location of the subject vehicle to the pre-defined subject vehicle path.  The GST then automatically and continuously drives to each position in its own predefined path which corresponds to the measured position of the subject vehicle.  In this way, the GST can arrive at the predefined impact point at the same moment in time as the subject vehicle, replicating the pre-crash motions and collision configuration in a repeatable way. If achieving a target speed at a specified (e.g., impact) point is crucial, the GST has an optional mode enabling it to switch automatically to a speed-following mode, when a certain condition in the subject vehicle (e.g., braking, or steering, or warning) occurs.

Minimized Risk
An important aspect of the GST system is that the risks to test personnel and the subject vehicle are minimized.  The low profile turtle minimizes the possibility of an impact with the subject vehicle structure and body work, and the soft car body is designed to be non-damaging to the subject vehicle, and is fabricated completely from lightweight foam. The panels are fastened using lightweight plastic hook-and-loop closure material, and uses no “hard” components which could potentially damage the subject vehicle body panels.  This facilitates testing scenarios which would otherwise be too hazardous to carry out with human drivers and full-scale vehicles. 

Quick Turnaround