The performance of installed systems in typical operational conditions can be affected by many factors, including installed antenna pattern distortion, multipath effects and propagation losses.
In addition, during the re-entry period, spacecraft often lose their communication link due to the plasma created by the interaction of the supersonic craft with the atmosphere.
For these reasons the prediction of link quality (link budget analysis) is essential, especially for those systems which may affect mission effectiveness, safety and success (e.g. the control and data links for unmanned aerial vehicles (UAVs), navigation aids (NAVAIDS) and aircraft communication systems). Link budget analysis is also useful for preliminary certification purposes.
IDS has developed a modeling tool for:
- The evaluation, all along the re-entry trajectory, of the communication transfer function between a vehicle surrounded by a plasma cloud and selected ground based stations.
- The evaluation of the communication link margin at predefined test points, taking into account aircraft attitude, multipath effect (reflection from the ground) and atmosphere effects.
This tool allows the identification of possible communication problems (e.g. blind angular regions and communication black-outs), facilitating an understanding of the reasons of such limitations and hence the ability to find cost effective solutions.