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The spatial target motion model exhibits a high degree of nonlinearity. This leads to the fact that it is easy to diverge when the conventional Kalman filter is used to track the spatial target. The Unscented Kalman filter can be a good solution to this problem. This is because it conveys the statistical properties of the state vector by selecting sampling points to be mapped through the nonlinear model. In practice, however, the measurement noise is often time-varying or unknown. In this case, the filtering accuracy of the Unscented Kalman filter will be reduced. In order to reduce the influence of time-varying measurement noise on the spatial target tracking, while accurately representing the a posteriori mean and covariance of the spatial target state vector, this paper proposes an adaptive noise factor method based on the Unscented Kalman filter to adaptively adjust the covariance matrix of the measurement noise. In this paper, numerical simulations are performed using measurement models from a space-based infrared satellite and a ground-based radar. It is experimentally demonstrated that the adaptive noise factor method can adapt to time-varying measurement noise and thus improve the accuracy of spatial target tracking compared to the Unscented Kalman filter.

Background: The COVID-19 pandemic necessitated wide-ranging adaptations to the organisation of health systems, and primary care is no exception. This article aims to collate insights on the role of primary care during the pandemic. The gained knowledge helps to increase pandemic preparedness and resilience., Methods: The role of primary care during the pandemic in five European countries (Austria, Denmark, France, Hungary, Italy) was investigated using a qualitative approach, namely case study, based on document analysis and semi-structured interviews. In total, 31 interviews were conducted with primary care providers between June and August 2022. The five country case studies were subjected to an overarching analysis focusing on successful strategies as well as gaps and failures regarding pandemic management in primary care., Results: Primary care providers identified disruptions to service delivery as a major challenge emerging from the pandemic which led to a widespread adoption of telehealth. Despite the rapid increase in telehealth usage and efforts of primary care providers to organise face-to-face care delivery in a safe way, some patient groups were particularly affected by disruptions in service delivery. Moreover, primary care providers perceived a substantial propagation of misinformation about COVID-19 and vaccines among the population, which also threatened patient-physician relationships. At the same time, primary care providers faced an increased workload, had to work with insufficient personal protective equipment and were provided incongruous guidelines from public authorities. There was a consensus among primary care providers that they were mostly sidelined by public health policy in the context of pandemic management. Primary care providers tackled these problems through a diverse set of measures including home visits, implementing infection control measures, refurbishing used masks, holding internal meetings and relying on their own experiences as well as information shared by colleagues., Conclusion: Primary care providers were neither well prepared nor the focus of initial policy making. However, they implemented creative solutions to the problems they faced and applying the learnings from the pandemic could help in increasing the resilience of primary care. Attributes of an integrated health system with a strong primary care component proved beneficial in addressing immediate effects of the pandemic., (© 2023. BioMed Central Ltd., part of Springer Nature.)