North Reference Point (NRP) of RS2

5) What is a NRP?

The north reference point (NRP) is a physical antenna feature which must be oriented toward the true north direction. Antenna calibration values assume that the NRP is properly oriented to true north. Please consult the antenna diagram for precise information on the NRP for your antenna model. Common NRP names and descriptions are given below.

Name Description
BAT battery compartment door release
BTD bottom of tear drop shape (wide end)
CAC nonspecific cable connector (only allowed for legacy calibrations)
CMP mounted compass
CTC external controller connector
DAC data cable connector (for data collectors besides external receivers)
DIS display/digital readout (DIS is a specific type of MMI)
DRY cap or cover for drying agent
MMI man-machine interface
NOM north orientation mark (placed on antenna by manufacturer)
PCS PC card slot
PWC power port; external power connector
RTC RTK connector; UHF connector for RTK broadcasting antenna
RXC receiver connector (connect antenna to external receiver)
TMT tape measure tab or notch for slant height pole
UNK unknown
If the antenna webpages and diagrams do not designate an NRP, it is unknown. See also FAQ7

What I get from this is that the RS2 is properly oriented when the on/off button is facing true north. Does that sound correct?

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Normally, there is a diagram showing this such as my Javad T2

However, there are a lot of receivers like Emlid’s that don’t have a diagram, such is the reason for the codes.

I have to agree with you, the power button is the NRP.

Thank you.

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Hi @rjherman,

Both you and Bryan are right: the power button should be oriented to the North.

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This is the first I’ve heard of having the RS2 pointed north. Is this somewhere documented online and I missed it?

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Read the first post, pretty much self-explanatory

I just stumbled across this information while checking out antenna calibration information on the NGS site.

I am also surprised !!! the first time i hear it

No I understand it. I’ve done this with other units in the past. My concern is that this was never shared on anything I’ve read educating myself on the use of any of the Emlid products. If my memory serves me well, I thought I recalled reading we didn’t need to do this as the unit could determine it’s orientation and the set the offset to make the collection due north.

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Pointing the device towards north doesn’t really matter for RS2, if you look the data from the IGS antenna calibration.
There is no horizontal offset from the center of the mount-point, and there is no horizontal offset between L1 and L2 phase centers.

However, looking at minimizing non-systemic errors, it does make a lot of sense to always orient the receiver in the same direction for the entire job.

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If I’m reading this correctly, doesn’t matter what direction but rather the unit should remain static and which ever direction you start the collection, it should remain there for the entirety.

Orientation should remain the same while collecting different points. No need to maintain the same orientation during transport between points :smiley:

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I imagine this was the position used during the antenna calibration process.

I intend to us this orientation for the base station especially for PPP observations, will not worry about the rover orientation.

When submitting data to the NGS for inclusion into the NSRS, many issues such as setup, minimum of 4 hours, GPS only data, sandbags on tripod legs bases, type of receiver, antenna, etc. have to be documented. One of them is the correct orientation of the antenna or reciever to North.

The whole purpose of the antenna/reciever calibration is to determine the actual error of the offsets to L2 phase centers. This has to be considered when reducing the data. Some older antennas/receivers have as much as 2-3 cm offsets !

Quality control in observation data is key to any accurate position.

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