Feature Request: Base Mode Page

When I’m out in the field setting up the base mode page and entering manual coordinates on my base (RS2), I reach the antenna height section and forget…is it height to ARP (threaded mount of RS2) or height to L1 phase center?

Can text be added to that section of the page to specify which of those two options base mode page is expecting to be entered for its calculation?

My memory tells me it’s L1, but I always question it in the field.

It is the point to the bottom of the receiver (ARP). The 134mm offset is accounted for in the software.

Now I’m truly confused because the link says, in two adjacent sentences, both:

Antenna height is measured as the distance between the mark and the antenna reference point (ARP)


For Reach RS2, consider the antenna height as the distance between the mark and the bottom of Reach RS2 (h on figure 6) plus 134 mm.



Hey everyone,

Let me explain this.

When you’re entering the base coordinates manually, you need to specify the antenna height as the pole height + 134 mm for Reach RS2 (or 65 mm for Reach RS+). We’ll think about how we can make it clearer in the app interface.

Regarding the terminology, we’ll sort it out in our docs, thanks for noticing! The correct way to put it would be that the antenna height for your base station is the distance between the point on the ground and the APC of the unit.


Could you implement it with two input boxes:

  1. Pole Height to ARP
  2. ARP Height to APC (and last used is automatically saved after reboot)

This would allow the user to input the ARP to APC height for their antenna (RS2, RS+, or any of the many antennas that can be used with the M2). Then in the field, the only thing to enter is the height to ARP. The advantages of this are:

  1. quick visual confirmation of correct antenna
  2. no calculations in the field to add ARP distance to APC (which should be double checked for QA, or could be forgotten to be included by inexperienced staff)
  3. because of no calculations to get the APC height above the mark, it’s less time needed to set up the base.
  4. it’s very clear what values should be used in each of the two boxes


Thanks for your suggestions! We’ll definitely take them into consideration.


Why is this not as simple as it should be ? Now I’m confused. I started playing around with the Reach 3 app and the antenna height is per the instructions… Measure to the ARP (antenna reference point). The software knows what the APC (antenna phase center) is based on what receiver is used. The user shouldn’t have to enter the APC.

Every GNSS software I’ve used, uses this methodology.


I’ll be verifying this on known vertical marks when my back is better… this is very confusing

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Perhaps if they made their software more specific for the RS2 several things could be added that would not be needed in the M2.

Yes people are using the M2 for an inexpensive base but those of us that want to use it in a professional setup do not mind the RS2 price. It is still much better priced than the big boy brands.

I am still waiting on saving base locations. I don’t need very many saved, 2 or 3 would be fine, if you could download/upload them to/from your laptop. I hate manually entering the base data. It becomes one more little thing that can induce an error into all your data that could easily be avoided by saving base data.


Last week I did a test on a known benchmark with an RS2 base casting to a server running snip and recording the output. It did show that you need to manually add 134mm to the antenna height for the broadcasted position to be correct.

I agree it would certainly be an elegant solution for the software to autodetect which unit was running as base and in the case it was an M2 it could have an option for manually adding the ARP to APC distance, but if it was the RS2, it would add it automatically.


Hey everyone,

Thanks for your suggestions! We’re definitely improving our Base position tab so that it can better suit your needs!

Currently, you need to enter the pole height and the distance between the bottom of the device and APC. When you’re using your unit as a rover, the ReachView 3 app adds this distance automatically depending on the unit so you don’t need to enter extra information. The pole height is enough.


Ive found the manual, diagrams etc confusing too.
And then when I use ppk software its dist to phase centre. When I enter for online ppp its again unclear.
Things could definitely be made clearer. 134mm is significant.
What would also be handy is examples of how to compensate if you did use the wrong input.

Hi Troy,

We’ll definitely think about how we can make our documentation on the subject clearer! If you have any questions about the base position or the base height, I’ll be glad to answer them.

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2 posts were split to a new topic: How to specify the base position

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