NRP to face True North on Reach RS2

[jmonaco (john.monaco@sierraproaerial.com)]

OPUS recommends “rotating the receiver’s NRP to face True North.” How does one find the NRP on a Reach RS2?

[s.pavlov (Sviatoslav Pavlov)]

Hello @jmonaco ,
All Reach Units don’t have north, since they have built in 9dof. This makes the rotation around the axes to be 360 degrees by default.
Hope it helps!
Best regards,
Slava

[bide]

@jmonaco

OPUS recommends “rotating the receiver’s NRP to face True North.”

I think what they are getting at is that if an antenna had a significant eccentricity (or x,y offset), then you can eliminate that as a source of error by always facing the antenna in the same direction. (your several measurements all have the same offset, so it is cancelled out)

Just like if your rover pole got stepped on and bent and the bubble was not recalibrated. Then you can eliminate that error in the same manner - by always facing the pole in the same direction.

And then you can further eliminate any absolute error in your survey by localizing over a known point. (removing the overall offset induced by the bent/uncalibrated pole or eccentric antenna mount, etc.)

[tatiana.andreeva]

Hi @jmonaco,

I agree with @bide.

The built-in IMU has no effect on rotating to North. The main point is to face the receiver in the same direction during all the measurements to compensate for some of the antenna phase center offset.

Please note that this offset hardly can be more than a couple of millimeters.