The Position System is concerned solely with the determination of the vehicle's

global position and orientation and is necessary for the controller to perform accurate

autonomous motion. The vehicle's position and orientation information is provided to

the system upon receipt of a "Query Global Pose" command from either the Operator

Control Unit or the Intelligent Primitive Driver.








 Ground Plane






Figure 2-6: Vehicle orthogonal coordinate system

 2.3 Sensor Systems

 There are three main sensor systems used by the Andros system: the stair counter

assembly, the auxiliary track position system, and the JAUS positioning system. These

systems provide feedback essential to the controller's ability to execute behavioral

commands.

2.3.1 Stair Counter Assembly

 For the stair-climbing algorithms to function properly, the control system needs to

know the relative position of the Andros on the stairs. Typically, a Global Positioning

System (GPS) would be used to provide location information in a robotic system.

However, staircases are found in or around buildings, which generally limit the

effectiveness of a GPS system; if satellite transmissions to the GPS receiver are blocked