Do I need to input the ARP-APC distance anywhere in SW maps to ensure accurate vertical measurements? I already have the pole height to the ARP set up as pole height. Is there anything else I should be looking for or need to input to make sure my measurements are good? I am already using the proper geoid file for my area.
Well, that depends on how the Firmware is setup for your device.
Here’s the serial from a torch sitting on my desk ( I don’t have a TX2 in front of me) :
Apparently the last time I used it was testing tilt mode accuracy, since apparently I haven’t changed the Rod Height back to Zero, yet.
I use 129mm as an average of the bands, but some people use the L1 or L2 measurement.
The APC of the GPS bands for this formfactor are as follows:
- L1 Up: 131.71 mm
- L2 Up: 126.18 mm
- L5 Up: 127.92 mm
Normally, I would have Rod Height and APC set to ZERO in the Firmware.
If you want the best elevations, manually measure your Rod several times from the tip/point to the ARP (bottom of TX2) and take the average. Then add the APC (129mm). That is the Height you would enter in SW Maps. If your Rod is adjustable, lock it down in a repeatable position and measure. Don’t use the graduation marks (heights) on the Rod for your Rod Height.
You can also manually set your Rod Height so the ARP is 129mm shy of 2meters, or 6feet, etc (anything easy to remember), and mark it.
Note: The TX2 might not have the instrument setup in the FW menu, since it’s not a Tilt Model. But you will need to account for the additional 129mm (APC) somewhere.
It also depends on whether your receiver is using an ANTCAL file. If it is, the receiver is computing the position of the ARP. If it is not, the receiver is computing some slightly messy approximation of the average APC, over the azimuths and elevations in use, and the frequencies in use. A good rule of thumb is “F9P means no ANTCAL file” because it (unreasonably IMHO) lacks that support.
You should think about how the GNSS RTK solution is processed to obtain a position for the pole tip in order to decide what to do. Indeed Tilt Mode and Not Tilt Mode is an enormous issue that cannot be overlooked without massive errors.