For precise work, especially where the height component is important e.g. control station establishment, the process of double window averaging should be undertaken using a SmartRover or Base & Rover. You should observe an averaged window of around 3 minutes (180 positions set in your “Point Occupation settings”) followed by another averaged window of the same length separated from the first by a suitable time period e.g. 20 minutes.
On average, a time separation of 20 minutes will yield a 10 – 20% improvement in coordinate accuracy and a 45 minute separation will yield improved accuracies at the 15 – 30% level compared to a single epoch solution. Window separations of greater than 45 minutes do not typically provide appreciable further improvement to the determined coordinates.

Source: “Guidance Notes for GNSS Network RTK Surveying in Great Britain”, Issue 2, April 2012, Page 4, The Survey Association (TSA).