The impact of tropospheric propagation on data fusion from multiple radars

Data fusion from spatially separated radars is increasingly being considered within network centric warfare to mitigate complex threats. Propagation of signals from spatially separated radars through differing atmospheric environments, however, can introduce significant errors in target positioning and ranging. For example, simulations illustrate that two radars separated by 100 km viewing the same single target through different tropospheres could place the single target in positions separated by over 200 m. Attempts at fusing the data and resolving the information into a single object could result in operational deficiencies due to classification and discrimination errors. Additionally, anomalous propagation conditions such as tropospheric ducting can lead to radar coverage holes and hence the perception of faulty radars and system level fusion errors. These errors must be characterized and, as far as possible, eliminated if the operational effectiveness of cooperative radar engagements and capabilities are to be optimized. This paper illustrates the type and magnitude of these errors, and their likely impact on system level fusion. The architecture of a potential correction system is outlined.