Post-processed stop-and-go survey – are we there yet?

Greetings. The release notes for ReachView v2.11.0 mention the following new feature:

Surveying: point collection start and end times are saved into the project

I’m interested in the so-called post-processed stop-and-go survey mode (PP-S&G), in which you’d occupy each GCP for some time before moving on to the next GCP, while keeping the GPS unit upright and logging raw data all along.

I was wondering if the time stamps are exported only in the list of position coordinates or also in the raw RINEX data?

Time stamps in the coordinates would allow us to isolate the points that belong to a given feature more easily. Instead of trying to visually find a cluster on the map, we could break up the series at the exact occupation start and end times.

But AFAIK the actual averaging is currently implemented only very crudely in RTKLIB. First because you have to manually select the occupation period for each of multiple GCP. Second because RTKPLOT’s “Show Statistics” setting performs a simple mean instead of a weighted one.

Now, if ReachView would output time stamps in the raw RINEX data, I could import it into any other post-processing software (e.g., Topcon Tools) and the weighted average would be calculated automatically and separately for each GPC. The RINEX specification offers event flags for new site occupation (stop) and movement start (go), followed by a MARKER NAME record.

In summary, I’m hoping that I could use Emlid Reach RS for PP-S&G data collection, even though I understand that RTKLIB doesn’t fully support this feature yet.

Below I give links to related discussions, here and elsewhere.


Related discussions elsewhere:

Related code:

Related threads:

Yes, this could be a very productive alternative to RTK. I think a lot of people are interested in doing it this way when there is no radio reception or cell data link available.

In ReachView, the Survey tab and the Survey Projects that you create should be viewed as sort of an add-on standalone feature. It consumes the position output (and status) of the receiver, and based on your project settings, it will perform an averaged point collection.

So, no it has nothing to do with the pre-processed data (RINEX/UBX), and everything to do with the final position output.

Time stamps are two things really. If you want the time stamps that can be inserted into the raw data, then you need to use the event marking pin on your Reach or Reach RS. Understand that this is not a start or a stop time, this is a nameless mark which is placed in the log at a precise time.

Maybe it would be possible to “simulate” an event while in a survey project, and do it each time you start and stop a point collection. That would be a good feature I think. (hint - make a feature request!) :slight_smile:

Hi Felipe,

You can use EZSurv post-processing software to PPK stop&go data files.
With EZSurv post-processing software a tool allows you to convert your ReachView CSV file into an EZSurv post-processing project. Then the sites from stop&go are upload into EZSurv post-processing software along with it log file.

EZSurv is a professional, very easy to use, post-processing software.
It can post-process:

  • flight data recorded with Emlid and it will also interpolate camera events positions
  • GCPs or any stop&go data recorded with ReachView

Moreover, EZSurv allows you to input/output the data in the projection of your choice (based on your County projection, datum and geoid).

To try EZSurv:

Thanks for the information, Stephanie. That’s a clever workaround from EZSurv, given the current limitation of RearchRS firmware.

Recall that RearchRS doesn’t output raw RINEX data with the start and end times of stop&go occupations (e.g., GCPs). That prevents most GNSS post-processing software to automatically average the epoch-by-epoch results and obtain more precise GCP coordinates. Of course, the user could still manually split the continuous session into discrete occupations, if they knew their corresponding time intervals.

Enter ReachView CSV output. It gives you the start and end times, along with the RTK coordinates. The coordinates themselves can be discarded, since they will be improved in post-processing. But the times are precious information, now cleverly reused by EZSurf.

I’m finally more comfortable purchasing ReachRS for surveying work.



EZSurv also allows you to do quality control on your RTK results.
So you also want to keep the results from the field in the CSV file.

When EZSurv uses the ReachView CSV file, it read your RTK results (fixed, float or single). After PPK, EZSurv provides a weighted average for your CSV sites, but it also provides a table with RTK (fixed, float or single) vs PPK results, it gives the difference in X, Y, H (RTK s PPK). Therefore you can keep your RTK results, make sure it fits your PPK results (to make sure no human errors were added) and of course use PPK results for points that were not RTK fixed.

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Hi guys,

It’s been a long time ago since the last message was posted here :smile: We’re developing our products constantly, and the Stop & Go with ReachView 3 feature is already released in our free post-processing software Emlid Studio. You can give it a try and share your feedback on the new topic!

UPD: Fixed the typo

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