Set antenna base height

Hi there

I am on a pair of Reach RS2 set for RTK using base + rover. While I can set the Pole Height (i.e. antenna height) of the Rover, I can’t set up the antenna height of the Base.

After scouring through the forums, it seems that I can only define the base height in manual mode. How can I do it in auto mode?

Or, should I record the coordinates of the Base, then use the manual definition?

In Auto mode, the antenna height should be zero as it as getting its LAT/LON/ALT for its position. In manual mode, you are entering each.

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In any case, if doing RTK, your base should be in manual mode anyway, regardless if you want centimetric accuracy relative to your base only or absolute accuracy.

Not all true, if setting it on a known surveyed point, true.

I seldom have that in my situation. I set my base by averaging from our CORS network for 5 minutes

But after averaging, don’t you save the averaged values as the base position? That’s in effect entering manual coordinates.

Yes I do but that is after I got the data. Not always or as you stated in any case.

For that day or time frame I am working there, I leave it on average. The only way it averages again is if it powers off. If I come back to the job sight the next day or after any time frame, I mount my base in the exact same location then manually enter the coordinates that I recorded from the initial average.

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I see where you’re coming from. Is it because you don’t need to measure any points on your rover but mostly want precise positioning for machinery guidance?

If OP, as his post seems to indicate, needs to do repeatable RTK surveying, HI is absolutely needed (unless it is always exactly the same) and providing correct values after the fact would make it PPK. The question would make no sense otherwise and he pretty much needs to enter manual coordinates (from a known point or from averaging) and instrument height.

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If you know the coordinates of your base then enter it in Manual mode and input the HI.
Once the base coordinates are saved in Manual mode then it’s available even after you turn off the unit and controller.
What I do is place my base on a pole with a constant height. I use this pole for the base everyday. I have established a base point on the roof deck of the office so I just place the pole at the same point every time we need to do a survey within 10km of the office. So I just accept the base coordinates & HI. Just check on the coordinates as a quality check procedure. I find this the better option than having to worry if I have entered the correct coordinates for the base everytime we have a survey.
That’s one thing less off the check list.
PS: You need to add 0.134 to your HI in Base Mode. In Survey Mode, it’s automatically added to the pole height. That’s one thing I think Emlid should revise. It should e added automatically to both instances.

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ok, so after letting the base coordinates average , then enter the base antenna height?

for auto mode, does this mean that Base antenna height is not an important parameter?

Base antenna height is an important factor. When in auto mode, the unit gets its LAT/LON/HT when it averages the data (single solution or using NTRIP/CORS). That is the height of your base in that position.

Gabriel, yes we collect data with our rover. All of our data is relevant to the base LLH. We install subsurface drainage tile and touch up or create waterway ditches in the agricultural industry. We have several methods of placing the base in the exact same location so that the same LLH in the base give the same data to the rover when we return. Sometimes this can be the next day, others it could be up to two years later.

Hi Benjamin,

Let me explain this.

You can specify the Antenna height in Manual input mode. In the Average modes, the height already contains the height of the antenna. You don’t need to enter it further on.

If you need to use this base position once again after averaging, it’s better to save the coordinates somewhere. So that you can manually input it the next time. This will help to keep the results consistent.

I believe Placing the base guide might be of interest to you.

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Ben,

If you average your point with a pole height of 2 meters. The coordinate you receive will be at that two meters above the ground (since you do not provide it an antenna height while averaging).

When you return to the point again, simply set the pole up at the same 2 meter height, and then enter the averaged coordinates in to the Manual Mode, with an antenna height of 0 (since you set it up the same height as when you averaged, the is no real antenna height to account for).

I don’t know how the reach 3 app works yet. I use the basic reach view app for static with my M2’S. I input the antenna height in the app. I usually use either the standard .ubx file and also rinex version for the file. When finished with a static observation, I use either the of the files for PP in whatever software I use. CHCNAV uses the native .ubx file. Javad Justin can use the rinex file. The antenna height is shown during import of the files. This is the reference height above the survey mark. Final computed position references the ground point of the mark.

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thank you all very much! the explanations are succinct and answered my query.

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