TD-88Up: Upgraded neutral Earth's thermosphere total density TD-88 model

Improved constants of the total density TD-88 model for the Earth's neutral thermosphere are calculated. The model is fully functional within the height range of 200 to 500 km, with fixed values of the mean solar flux and geomagnetic index. The control data of the atmospheric air density are derived from the aeronomical NRLMSISE-00 model which was used as the reference one. The upgraded TD-88, named TD-88Up, model is obtained by the extended LSQ method with varying all model parameters