Modeling and Simulation

Modeling and simulation are key capabilities in the areas of test, research and development. CIE has developed simulations for clients as well as for in-house use in the development of products.

For the FAA, CIE developed an extensive model of Radio Frequency Interference (RFI) characteristics called Cosite. The Cosite program allowed FAA spectrum planners to input the current configuration of an existing remote ground-to-air radio site and model the components of interference generated by harmonics of the fundamental carrier frequencies as well as the intermodulation products of multi-frequency sites. Since a limited number of frequencies may be available for any particular site, this tool allowed planners seeking to add a new frequency to a site to try different ones to see which caused the least interference within the context of the model. This saved the strain of implementing the frequency in the real world only to discover it was unworkable because of unexpected Cosite interference. Parameters such as antenna gain, antenna position/separation, Linear Power Amplifier output and cable loss were also included in the model.

CIE also developed a Voice Channel Emulator (VCE) which allowed the simulation of a multi-user air traffic control sector. This was created to test the effects of channel impairments such as delay and noise as well as environmental factors such as traffic loading and transmission contention on the acceptability of a digitized voice transmission scheme being investigated by the FAA for their next generation of ground-to-air VHF Digital Radios. Several systems were built and used by Human Factors personnel in an in-depth study with actual pilots and air traffic controllers. This study resulted in the validation of digitized voice for use in the safety critical application of air traffic control.

Other efforts include the development of simulators for interfaces between pieces of equipment which are being built along different timelines and thus are not simultaneously available for validation with one another. In this case the simulator provides validation for the earliest arriving equipment.

CIE Engineering, Inc. • 6001 Woodlake Lane • Alexandria, VA 22315 • Phone: (703) 922-7061