The desire for use of autonomous robotic vehicles has undergone tremendous growth in the past decade. One of the greatest challenges to the successful development of truly autonomous vehicles is the ability to link logically based high-level mission planning with low-level vehicle control software, without a labor intensive programming effort for each mission. This challenge can be effectively achieved through the use of tri-level control software architecture, as described in the Rational Behavior Model. The control software (in the tactical level) must de-couple the high-level mission planning from the low-level vehicle control software to reduce the programming effort for each mission. This report describes an object-oriented, modular architecture for the middle (tactical) level that uses concurrent programming techniques and multi-language interfacing. This design enables the control software to handle the intense data management effort required to operate in an autonomous fashion and interface with code already perfected for use in the strategic (top) and execution (bottom) levels. The design was evaluated by providing the tactical level with a simple execute order statement that was then used to drive the actions of the vehicle. The software package demonstrates the validity of the design and provides the framework for full implementation on an actual vehicle.