[Xastir] Moving vehicle speed

[David]

Hi All.....i have had it bought to my attention that my Xastir system is 
showing and t/xing the speed of vehicles at a very fast rate....eg 
VK3HCZ-9 @ 948km/h.....i think this should be 48km/h
this has only started to happen within the last few days ...i did a 
update-xastir command a couple of days ago and it has seemed to happen 
since then.....

any thoughts or ideas on this problem

73 David VK4BDJ