Survey Export Field Specifications

Hello,

Is there a document explaining the exact definitions of each field in the survey export files from ReachView 3?

I’m particularly interested in the meaning of the Ellipsoidal height and Base ellipsoidal height fields. The base ellipsoidal height appears to remain constant regardless of the base height entered into the logging section of the app, which suggests that it is just the height of the APC of the unit.

Is the same true of the rover’s ellipsoidal height? (Meaning, I subtract the Antenna height value from the Ellispoidal height to get the “true” ground height.)

As an aside, how is the base height used? I know it appears in the RINEX log, but does it have any relevance to the values in the survey export?

Hi Rob,

It’s not in our docs yet, but you’re in the right place to get an answer!

The Base ellipsoidal height field contains a value that the rover receives from the base. So, you are right – it corresponds to the base’s antenna phase center.

As for the rover’s heights, both Elevation and Ellipsoidal height show the correct ground height, which takes the entered antenna height into consideration.

If you are interested in any other fields, let me know!

As an aside, how is the base height used? I know it appears in the RINEX log, but does it have any relevance to the values in the survey export?

Do I get it right that you mean the height to the bottom of the receiver that you can enter in the Raw data settings? It’s used only in PPK, so it’s not related to the values in the CSV export. But it helps when you post-process your data in Emlid Studio, as the measured height will be added automatically.

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Thank you very much for the reply.

For the base settings, I’m actually asking because we’ve been using NRCan’s PPP to correct the base’s position. We tend to survey in very remote environments where there are no benchmarks, no network access, etc., and I’m actually wondering if it’s even necessary to enter a base height at all. We don’t care about the base’s true position because the chance that we’ll ever revisit and find the precise location of the previous occupation (we’re generally not allowed to leave any permanent marks) is pretty much nil. We really only care about the rover positions, so if I leave the base height at zero, it saves both the field workers and the office workers a bit of effort. We just need to apply the difference between the PPP position and the base’s position (in the CSV file) to the rover positions. (For the kind of work work we’re doing, the accuracy of PPP is sufficient.)

Does my reasoning make any sense here?

Hi Rob,

Sounds fair to me. Since you need to determine the base’s antenna phase center in PPP, you can indeed leave the base’s measured height at 0 m.

One important note: if you record RINEX logs with Reach RS2, the antenna type will be added to the RINEX header. Services can read it from the log automatically – in this case, you’ll get ARP instead of APC.

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Yeah, that’s right. I’ll still have to make an adjustment, but at least it’ll always be the same value (for the RS2). Thank you for the help!

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