Difficulties with getting fix in PPK

Reach Module / M+ / M2 RTK / PPK configuration
1

Good day all,
I have a similar problem as above. I just got the RS2 (3 units i.e a base and two rovers) and I have been trying out to compute position of points but the position is not fixing from PPK work flow using RTKPOST

My setup is that I set up base on a know point in our local system (UTM 31N Minna Nigeria) and rover on an unknown point. The baseline is not up to 4 kilometers with over 30 minutes raw data observations on the rover station.

Can I get someone to work me through this.
Attached are the raw rinex data for the base-rover observations.
Thanks as I look forward to a response.
Olubola

raw_202010131450_RINEX-3_03.zip (3.8 MB)
raw_202010131456_RINEX-3_03.zip (2.3 MB)

2

I can’t get it to fix in either RTKpost QT or EzSurv.
How does your environment looks like ?

3

The environment is built up but the units were getting well over 30 satellites all through the observations

4

Yeah, it’s a bit tricky one. I can get around 50% fix ratio when using L1 data only in fix and hold mode. Less in Continous mode.

Only thing I can think of is interference or multipath issues.

1 Like
6

Ok. Good.
Can you help put me through how you seive out other frequencies to remain L1.
Thanks

7

You just select it from the dropdown in RTKPost.

1 Like
8

Hi Olubola,

Welcome to our community!

Some satellites may be not high enough above the horizon, so they have low SNR values. Surveying under light foliage and with obstacles like trees or buildings nearby can lead to an unstable SNR value as well.

You can exclude the satellites that are low above the horizon from calculations using the higher Elevation mask. You can also switch from Forward processing type to Combined. It will close the gap between fixes by tackling the job forward and backward and combining the results.

Like Christian, I can get 50% in Fix with the L1 band chosen. If the Combined mode is enabled and the Elevation mask is set to 20, it gives 75% in Fix.

2 Likes
9

Thank you for your inputs @kseniia.suzdaltseva and @wizprod. I got it!!
I appreciate.

Another problem I have is working in our local coordinate system (UTM ZONE 31N). It’s problematic having to convert each of the coordinates from long/lat/h to UTM xyz, losing some precision due to conversion…

Thank you as always
Olubola

10

Hi Olubola,

You can work in UTM zone 31N in our beta ReachView 3 app. You can install it on your Android or iOS. Please note that it doesn’t have all the functions and settings currently, so it’s integrated with ReachView 2.

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