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?
No I understand it. Iāve done this with other units in the past. My concern is that this was never shared on anything Iāve read educating myself on the use of any of the Emlid products. If my memory serves me well, I thought I recalled reading we didnāt need to do this as the unit could determine itās orientation and the set the offset to make the collection due north.
Pointing the device towards north doesnāt 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.
If Iām reading this correctly, doesnāt 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.
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.
