Various debugging - need to delete all that first.
Just with 3 that didn't work
Small
Reverting to older version, prior to various debugging code
Removing as.POSIXct - instead using datetime as character throughout
Modified LMM analysis
Reduced to cluster of 20, not 40
New script looking at altitude accuracy to GPS data
LMMs to look at what effects flight altitude
Final working version!
Had to delete one data point from database 'lund_gps_paramaters' - there was one point where the date had year 2018 - i.e. not possible (2013 now)