Post by Ian Gillespie on May 9, 2018 20:34:51 GMT
I was fixing posts in bush the other day using the GPS and then followed up with the total station because the coordinate qualities weren’t very good.
Taking the total station positions as the correct position I have compared the GPS coordinate quality with the distance between the total station and the GPS position (in 2d)
There were eighteen posts.
The QC’s ranged from 0.36 to 1.06m with a mean of 0.67m ( I believe this is 1se)
The difference to the total station position ranged from 0.6 to 5.9m with a mean of 2.6m.
The best ratio of the CQ to the observed error in position was one but the mean was 4 times the coordinate quality and the worst was 7 times the coordinate quality.
So I guess this just tells us what we know – coordinate qualities over 10cm fall off in accuracy pretty quickly.
Taking the total station positions as the correct position I have compared the GPS coordinate quality with the distance between the total station and the GPS position (in 2d)
There were eighteen posts.
The QC’s ranged from 0.36 to 1.06m with a mean of 0.67m ( I believe this is 1se)
The difference to the total station position ranged from 0.6 to 5.9m with a mean of 2.6m.
The best ratio of the CQ to the observed error in position was one but the mean was 4 times the coordinate quality and the worst was 7 times the coordinate quality.
So I guess this just tells us what we know – coordinate qualities over 10cm fall off in accuracy pretty quickly.