62 
Oxford Technical Solutions 
 
Figure 23. NAVconfig Primary Antenna page 
 
 
It is necessary to tell the RT the distance between its measurement origin (shown in 
Figure 6) and the GNSS antenna’s measurement point. This should be entered in the 
vehicle’s co-ordinate frame. 
The accuracy of the measurements should also be specified, and care should be taken 
here. It is very easy to measure within 1 cm or better in a straight line, but it is much 
harder to measure within 1 cm through a car roof. This is compounded if the RT is 
slightly misaligned in the vehicle. Any alignment errors should be included in the 
accuracy you believe you can measure to. 
Telling the RT you have measured the distances within 5 mm may lead the RT to believe 
its results are better than they really are. You may be impressed by the accuracy the RT 
reports, but in reality it will not be that accurate. It is better to overestimate the accuracy 
(i.e. tell the RT a worse value) than to underestimate it. 
The RT will try to improve the position of the primary GNSS antenna during use. To use 
the values the RT has estimated use the Get improved settings utility on the Orientation 
page. More information about Get improved settings is provided on page 59.