Collecting & Staking / Setting Out Points (BASE AVERAGE SINGLE)(Multiple days)

[timd1971]

(2) Reach RS (Edison chips)
(1) as the BASE
(1) as the ROVER
LoRa communication between them.

Just to make sure everything is ok here, got a question to help clarify things.

Set my BASE up anywhere in the area of work with best clear sky view and highest elevation.
I let it AVERAGE SINGLE for a few minutes. (not using NTRIP CORS) (I mark where the BASE is physically for day 2 work)(note: In my case I do NOT need to use a KNOWN POINT from public or surveyor provided records etc to set on. I generally localize using FieldGenius for each new project).

I get a FIX on my ROVER and can start collecting and staking points as needed usually within a couple minutes depending on conditions.

Should I be writing down my BASE coords/ellipsoid height?
And/or use (and write down):

From DOCS:
Save averaged position to manual
After you have successfully obtained averaged position you might want to save it for future use. Click on the “save coordinates” icon and position will be saved as if it was entered in manual mode. Now every time Reach starts it will broadcast this position in correction messages.

https://docs.emlid.com/reachrs2/common/reachview/base-mode/#average

Since all my ROVER measurements will be RELATIVE to the BASE (and whatever coords it’s averaged SINGLE at start), if I return the next day (if not finished the 1st day), Can I just set the BASE on the SAME MARK as the day before, or wouldn’t my new 2nd day measurements be offset incorrectly in relation to the BASE even if placed physically on the same mark since it is AVERAGING SINGLE again on Day 2?

Or should I be entering the AVERAGE SINGLE coords and ellipsoid height (from Day 1) MANUALLY for Day 2 and any consecutive days after? Kind as if I had a KNOWN point, and just use this everyday at the project at the start.

Seems I should be, but just want to get professional clarification.

Thanks everyone, much appreciated!

PS. I am also wondering if @agrimgalina was having this problem a couple days ago because of what I am describing. Maybe he measured points in an earlier point in time using AVERAGE SINGLE (BASE), returned at a later point in time, AVERAGE SINGLE (BASE) again instead of using the recorded point and therefore his measurements are off? I want to prevent this. Again, what I do is not professional survey related, so no worries! ; )

[timd1971]

probably answered my own question from the DOCS:

There are two main options how to specify base station position. Note that RTK positioning is relative to the base station, so any inaccuracy in it’s position will result in a constant shift of rover coordinates. For many applications it is not critical and averaged single coordinate of the base could be used. If your application requires absolute accuracy for rover position an accurate base coordinate must be entered.

So basically if Day 1 I set up BASE, mark physical location for returning later.
Return Day 2, if I merely just place the Base on the mark without using the previous day AVERAGE SINGLE cords, then everything will be shifted relative to base’s Day 2 AVERAGE SINGLE coords. So yeah, not good if the Day 1 coords weren’t entered prior to begin of Day 2 project continuation.

[wizprod (Christian Grüner)]

Correct, average single on day 1, note them down in your phone, so they can be easily copy/pasted into Reachview on day 2

[Zinou (Zinedine)]

I can add also that the coordinates of the base must be the same for the day 1 and 2 if I want to make a point stakeout in the same system (the case of a division of agricultural land for example).

[timd1971]

Thanks guys. Haven’t had to deal with a larger multi-day project involving setting up and taking down the base on a daily basis yet.

Much appreciated.

[timd1971]

More GREAT info:

Finding Accurate Base Position

Your accurate measurements with Reach are made between the base and rover. First you have to supply Reach with an accurate base location yourself. The best way is to start at a place of known accurate coordinates. For example, a survey marker with published coordinates. Otherwise you could use corrections from a 3rd party. For example an NTRIP connection or by downloading historical CORS data. Hopefully there is a station within 10km of your location. The next best is to log data for a lo…

[timd1971]

Base Mode > Antenna height, m:

I wonder if to avoid confusion here, maybe, a note should be implemented next to this?
That Antenna height, m is only needed if setting on a KNOWN POINT. (From point on ground to bottom of Reach RS plus 65mm)
And Antenna height, m should be 0 only when averaging and using Save averaged position to manual.

Finding Accurate Base Position

If you are averaging base position your antenna height is zero. Non-zero antenna height should be used if base is set up on a known point. Antenna height is elevation from known point (which is usually on the ground) to antenna level (antenna is usually on a tripod). In your case you are directly measuring the location of your antenna using GPS, so base antenna height is zero.