I only have one Reach RS2+, want to collect accurate GCP

One Reach RS2+, no cell service, want to do PPK to get accurate Ground Control Points.

  1. If I am 50 Km from a CORS station and using Stop and Go with RInex logging on, how long do I need to occupy the GCP to get cm level accuracy?
  2. I ran Stop and Go in Emlid Studio using my local CORS Rinex and the Rinex from my static Reach placed in a tripod. The FIX solutions that result are a cloud of points over an area of about 5 by 10 cm. The Reach didn’t move. Why doesn’t this give the same solution as if I ran the Static processing using the same input data?

While you can correct your GCP to the geosciences australia bases, you’ll probably want to occupy one or two nearby SSM’s (You can get these details off landgate, make sure to use 2020 coords but AHD height, auscors operates in mga2020) I’d probably spend 2-5min before you fly and then re-observe them after you fly, average the 2 coordinates out once you’ve processed them for the gcp coords.

By cm level accuracy do you mean around +/- 5cm? You’ll need to wait a day to process your data but it should be achievable, note that just from the baseline itself (50+km) you’ll have 30mm Horizontal and 60mm Vertical positioning accuracy, hence the need to tie in to an SSM nearby.

I don’t use the stop/go processing but was the rs2+ in static mode or kinematic? you’ll see a cloud as it takes an observation every second.

1 Like

Hi @birdseyeimaging,

Sorry for the silence here!

In most cases, 5-10 minutes are enough for 1 point in Stop&Go. But it’s hard to provide the exact period that guarantees cm-level accuracy since the result highly depends on the local environmental conditions.

When performing Static processing, Emlid Studio gives the best Fix solution. If you run the Stop&Go processing, it calculates all the solutions first. Then, it averages them to calculate the points’ coordinates. That’s why the results can differ slightly.