The last three chapters gave you the opportunity to execute three-, five-, and six-DoF simulations of aircraft and missiles in the so-called batch mode. You gave the computer an executable form of your simulation and waited until the output came back. As outside agent, you may have yearned to get into the simulation and become a part of its world. Flight simulators, hardware-in-the-loop facilities, and war gaming let you be submerged into their virtual environments. To make the human experience real, the simulations must run in real time or at least be phased by real-time events.
The modeling techniques you have acquired will serve you well in building real-time applications. Preferably, you first construct a batch simulation and then synchronize it with a clock for real-time execution. You will have to balance model fidelity and execution time for best performance on your equipment.
Real-time simulations play a part at all levels of the simulation hierarchy. Recall from Chapter 1 the pyramid of modeling hierarchy. At the foundation lie the engineering simulations, modeling systems, or subsystems with great fidelity, ffardware-in-the-loop HIL simulations are used to check out the performance of the system’s hardware and software before flight testing.
At the next higher level are the engagement simulations, which determine the effectiveness of aerospace vehicles. In military applications blue and red platforms may be engaged, firing projectiles or missiles at each other. The testing of equipment and air crew is carried out in air combat simulators, a special form of a flight simulator. In commercial applications the cockpit simulator is used to test handling qualities and to train airline pilots.
The upper two levels, called mission and campaign simulations, are tools for strategy or war games. What they lack in engineering detail they make up by a large aggregate of vehicles. As the multitude of entities interact, operational effectiveness is evaluated, and winning strategies are developed.
My purpose is to give you a taste of each of these categories. Drawing from my own experience, I selected topics from piloted simulators, HIL facilities, and war-gaming exercises. The genre however is so vast that you have to consult the specialty literature for particular applications.