WEMSgen: A real-time weather modelling library for on-board trajectory optimisation and planning

WEMSgen is a stand-alone application developed within the Clean Sky FASTOP (Fast Optimiser for continuous descent approaches) project that is capable to load weather data in standard GRIB (General Regularly-distributed Information in Binary form) files and generate piece-wise polynomial fitting functions that can be used in a latter stage in trajectory planning and/or optimisation algorithms. Assuming a known lateral flight route, meteorological input data (temperature, pressure and wind field) is fitted into cubic B-splines as a function of the aircraft altitude and its distance to the runway threshold. WEMSgen can be queried in real-time by any process that needs weather data. Thus, besides being used for trajectory planning or optimisation algorithms, it also can feed aircraft simulation or visualisation applications, among other. WEMSgen has been successfully used and validated in a flight simulation experiment using the Generic Research Aircraft Cockpit Environment (GRACE) at the National Aerospace Laboratory of The Netherlands (NLR).