A strong component of current underwater robotics work lies in the realm of multiple vehicles and instrument platforms (VIPs). Successful fielding of functional multiple VIP systems will require that we first gain experience with the issues pertaining to the interactions between the participants, who must cooperate in order to accomplish complex and dynamic long term missions. Many current simulation tools are directed towards investigations into the motion characteristics of vehicle body styles and their propulsion systems. While these tools are essential in the design of vehicle bodies, they do not directly address the issues of cooperative behavior among a team of VIPs. There is a scarcity of tools geared towards the needs of researchers working with multiple cooperating VIPs. To answer this need, we have developed the Cooperative AUV Development Concept (CADCON).

The chief idea behind CADCON is that it provide an open and flexible simulation environment for use by as many researchers as possible. Understanding that no single simulation harness could capture the full fidelity of the real open ocean environment of a deployed Autonomous Oceanographic Sampling Network (AOSN), nor the complexity of every sort of vehicle that might participate, we have attempted to focus CADCON on one of the stickiest problems we see in systems as complex as an AOSN: the issues associated with the interactions among multiple heterogeneous agents; be those agents simulations, real vehicles, or human users. To that end, we specify that the CADCON simulation environment adhere to the following points:

• Utilize well-known ubiquitous hardware.
  All CADCON components have been developed to run on today's most available platform: the IBM compatible computer. This allows workers to leverage well known, cheap, and accessible hardware, making their participation in CADCON simulations relatively easy and flexible. Exotic hardware is not required.
• Utilize a well-known ubiquitous communication protocol.
  CADCON environment components are implemented following the client/server model and communication between them is in the lingua franca of the Internet: TCP/IP. This non-reliance on proprietary communications protocols further leverages the system's utility and availability to other workers.
• Be globally accessible.
  Since components communicate via TCP/IP sockets, they may be distributed across intranets as well as the Internet. This opens the door to geographically distant institutions participating in joint simulation scenarios.
• Open to any institution's AUV development style.
  The client/server model fosters modular development. Coupling this with the use of the TCP/IP protocol fosters a high degree of platform/language independence for client developers. This allows great flexibility for distributed researchers to connect existing legacy simulation models or create new models on the platform and in the programming language of their choice.
• Allow for real hardware in the loop simulation.
  The modularity encouraged by clients communicating with servers via TCP/IP also provides for easy integration of real vehicles into the CADCON environment. This moves CADCON out of the strictly simulation arena. Real vehicles will react to situations presented by the CADCON simulator while safely on the bench. Given a physical communication link, this concept can be taken even further to where real vehicles situated in actual missions will begin to supply the CADCON environment with in situ data.
• Access via the World Wide Web.
  The current instance of the CADCON environment is now available on the Web. In the spirit of open and free exchange of ideas, users are encouraged to download example clients from the AUSI web site and try them out against a running simulator.