Modeling and Simulation
Not all models are created equal
Previous attempts to resolve this issue failed to take into account the limited bandwidth available to general aviation pilots, as well as how differences in geography and regional flight profiles dictate the methods that different aircraft choose for receiving weather data.
Not all models are created equal. Some models are too simplistic, and some people think that limited data is “good enough.” We know that’s not the case, and we conduct physics-based modeling and simulation to ensure we’re doing more than just creating pretty pictures. For this project, we looked at the use of different networks in an array of situations in an effort to better support both civil pilots and large airliners.
Bandwidth available, bandwidth required
To find a solution, we had to think outside the box. Using the industry-standard OPNET toolset, we modeled the communications network for sending and receiving nodes. We then broke our analysis down into five major steps, to ensure we would be able to validate each portion of the task.
During the first phase, we investigated both the bandwidth available to weather services and the bandwidth required to provide the service. A regional simulation methodology was used, modeling three regions of primary interest: the New York-Washington corridor, the Rocky Mountains, and Polar-Alaska. Our study focused on four communications networks in common use: Automatic Dependent Surveillance-Broadcast, VHF Digital Link Mode 2, Inmarsat, and Iridium.
The Deadline Crunch
Impossibly tight deadlines are nothing new for KIHOMAC. One of the reasons government agencies are so quick to call our reverse engineering team is they know we can handle quick turnaround times. For this task, we were given three months to deliver a project that would typically require ten months to complete. Unfortunately, our customer was facing a hard deadline, and failing to deliver wasn’t an option we were willing to entertain.More about our company
We diagrammed the problem and wrote external code based on calculations showing everything that was required to send a signal from Location A to Location B, taking into consideration external factors like Doppler frequency shifts. Even after creating these models, however, we struggled to find a way to transmit files five to seven megabytes in size to older general aviation aircraft. We grappled with the question of how to send a large amount of data through an extremely small pipe. That’s where our systems engineering background came into play.
Ultimately, we solved the issue by developing a lossless compression technique. Looking at how the system would be used, we realized that pilots would never need to see icing and turbulence data for the entire country at once, since an aircraft can only fly so fast. We created a way to place limitations on the data based on the aircraft’s flight plan. Rather than receiving an entire data set all at once, pilots are sent smaller chunks based on their current locations. We then used a compression technique to reduce the file size even further. Ultimately, we saw a 60% reduction in file size.
We provided the FAA with a systems engineering analysis and a solution for turning proprietary data into weather maps that could be accessed by both general and commercial aircraft. By analyzing the feasibility of providing turbulence and icing data to the cockpits of civil pilots and commercial operators, we were able to show exactly what would have to happen in order for our ideas to be practical.
This project should ultimately end up saving everyone money, by eliminating the need for the operators of older planes to install thousands of dollars worth of new hardware in order to access the FAA’s weather data. Our solution also gives the FAA the ability to disseminate more data to civil pilots and large airliners. Although we were tasked with providing the FAA with nothing more than simulation and visualization, we were ultimately able to provide the administration with a systems engineering analysis and a solution to the end goals that they had in mind.