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MilCAN Data Bus
The CR2 PBISA CAN bus is the first implementation of the MilCAN A higher layer protocol on a UK military vehicle. The Physical and Data Link Layers of this CAN bus implementation are as defined in ISO standard, ISO 11898. The bus adopted for the CR2 PBISA system uses the 250 Kbps bus standard but to ensure adequate capacity for future expansion bus construction has been specified to meet 1Mbps parameters.
Development of the application software was undertaken on the Alvis Vickers P-BISA Platform Integration Facility (PIF). The PIF provides a lab environment representative of the CR2 vehicle and makes use of software emulators to simulate the operation of major system components. CAN bus operation within the PIF is monitored using the CANoe CAN bus development software.
P-BISA Processing Computers
Challenger 2 P-BISA, features two computing platforms working together to optimise the integration into the vehicle. The P-BISA Processor (PBPU) provides moving map and situational awareness data to a new display, and the Digitization Processor (PDPU) links the weapon system and navigation system. These two computers communicate across the MilCAN data bus.
Inertial Navigation System
The CR2 inertial navigation system is required to provide accurate pointing / heading information and also dead reckoning in the absence of GPS data. Two navigation trials were carried out to assess the performance of leading off-the-shelf systems and a trade off study carried out to select the most suitable system. Key to the operation of the new CR2 navigation system is the Driver’s Display Panel. This unit provides the Driver with information to allow him to navigate between specified waypoints with minimal intervention from the vehicle Commander. The Drivers Display Panel is located under the speedometer box and provides the driver with position data, distance to waypoint, and steer left/right.
Commander’s Crew Station
A new Commanders Crew Station (CCS) Display has been installed to provide moving map and situational awareness data to the vehicle Commander such as vehicle position and sight and turret orientation. This data is routed to the CCS display via the MilCAN bus.
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