Conserving Telemetry Bandwidth in Flight Test Instrumentation

Abstract

The more sophisticated weapons systems become, the more information is required for thorough system test and evaluation. With the increasing capability in instrumentation technology, more data is being generated, and this in turn is stressing the amount of telemetry bandwidth available. In the training community this is even more serious because of the extremely large training areas and number of players involved. Total data bandwidth required becomes an insurmountable problem. When examining the telemetry data requirements for each application, we must constantly remember that information transfer is the key, not necessarily the transfer of large amounts of data. This problem can be solved by applying instrumentation techniques that enable significant information transfer without requiring excessive data bandwidth of the telemetry system. The general approach to the solution of this problem has been applied to the U.S. Government's SDI Program. Here the total system is modeled in a computer, and a complete test exercise can be simulated. Only significant information from the vehicle under test is telemetered periodically to verify the simulation. Another approach has been postulated by the U.S. Defense Advanced Research Projects Agency (DARPA) in their SIMNET studies. Here an exercise is simulated both on the ground and in the test vehicle, and information is transmitted from the test vehicle only when the actual vehicle performance differs from the simulation. By using techniques of this type, savings of a factor of 10 or more can be experienced in the required telemetry bandwidth. This paper examines various techniques that can be used to minimize required telemetry bandwidth.