On Hourly Orbit Determination
   (Jan Dousa, Leos Mervart)

 Today, even using a PC and Linux operating system together with
 any effective method of evaluation, we can process the global
 GPS network counting more than 50 sites on hourly basis. We will show
 preliminary results of the hourly orbit determination focused on its
 availability, quality and possible utility for any near real-time GPS
 processing.
 The first step of our approach consists of the validation of procedure
 strategy by hourly based re-estimation of IGS final orbit product.
 In the second step we would continue by tuning the strategy and
 preparing the routine orbit determination.