LS-LS Base Pt problem

SynGeo

Member
We are using two TLS's over LTE or UHF, with one as the base and the other as a rover. After completing a survey, we copy the base file over to the rover and use either the recover base point, attach GNSS file and recover DPOS session OR the create base and dpos from file option. The problem is that the corresponding rover shots are not attaching to the DPOS session, so only the base is processed.

When examining a rover point, we notice that the base coordinates are incorrect, sometimes by a significant amount. Is there a way to edit these?

When we start the base, we've been shooting a point for 10 epochs and then using that as the point to reference the base, rather than using "from auto". I'm not sure if this is messing things up. Is there a published procedure for starting up an LS as a base?

It appears the problem is in the coordinates for the rover point. We've also tried the Sync DPOS tasks with no effect.
 

Matthew D. Sibole

Well-Known Member
5PLS
I have not operated that way in quite some time so this information may be antiquated. I collect a short vrs point. Then I start my LS base up by recalling that point. I then start collecting a WAAS float shot (this way it will store raw data the whole time I am using the rover). When I am done for the day I go back to the base and stop the WAAS float shot and store the point. This point that is stored is the one that will have the raw data associated with it and it will overlap all rover shots. I copy that points raw data file out of the base and use the recover base point function in the rover. I call the recovered base point the same number that I stored in the base. I then attach raw GNSS data (the WAAS float shot) from my flash drive to that point. I then hit recover DPOS session.

It sounds like you are doing everything right. What I do not know is if your base is collecting static data the whole time or just on the 10 epochs that you mentioned. If you are only collecting static data on the 10 epoch then there will be no overlapping raw data between the base and the rover.
 

Adam

Well-Known Member
5PLS
The latest prerelease starts the recording for you similiar to the traditional base rover setup. It works well.
 

Adam

Well-Known Member
5PLS
Also, make sure that process all raw gnss points is checked in the dpos settings.

I know, just saying there are improvements coming. It works really well.
 

SynGeo

Member
I have not operated that way in quite some time so this information may be antiquated. I collect a short vrs point. Then I start my LS base up by recalling that point. I then start collecting a WAAS float shot (this way it will store raw data the whole time I am using the rover). When I am done for the day I go back to the base and stop the WAAS float shot and store the point. This point that is stored is the one that will have the raw data associated with it and it will overlap all rover shots. I copy that points raw data file out of the base and use the recover base point function in the rover. I call the recovered base point the same number that I stored in the base. I then attach raw GNSS data (the WAAS float shot) from my flash drive to that point. I then hit recover DPOS session.

It sounds like you are doing everything right. What I do not know is if your base is collecting static data the whole time or just on the 10 epochs that you mentioned. If you are only collecting static data on the 10 epoch then there will be no overlapping raw data between the base and the rover.

We collected a shot using WAAS float for 10 seconds. Then used that point as a reference for starting the base. The firmware doesn't automatically collect data when starting an LS as a base, so we then used the record button on the action screen to collect the static.
 

Michael Stazhkov

Developer
JAVAD GNSS
In theory the LS as Base should record in the base file the same coordinates as rover received and recorded in rover files and points. So I think there is a way to correct the issue. But I need the projects.
 

SynGeo

Member
The latest prerelease starts the recording for you similiar to the traditional base rover setup. It works well.
I'll have to give that a try, as it appears as though you can get corrections, but not record the base.
 

Matthew D. Sibole

Well-Known Member
5PLS
We collected a shot using WAAS float for 10 seconds. Then used that point as a reference for starting the base. The firmware doesn't automatically collect data when starting an LS as a base, so we then used the record button on the action screen to collect the static.
Doing that on the action screen is fine but if it does not have a point to associate the raw data file to then it will likely be lost. That is why I always start collecting another Waas float shot before walking away.
 

Adam

Well-Known Member
5PLS
I was doing the same as Matt and use the waas profile to collect a point with raw data. Until, The prerelease fixed it, works great starting the point and raw data when you hit start base.
 

Michael Stazhkov

Developer
JAVAD GNSS
Did you try my recommendation how to recover your DPOS session? I think it should work.
The problem is in coordinate of reference station recorded in the base file. Actually it recorded twice: the first one is incorrect, the second one is correct but I take the first coordinate as reference station position. I will change my algorithm to take the last one (most probably it is correct).
So in current release on rover receiver during Base point creation to avoid getting the wrong reference station coordinate from the file we have to create the Base point from any rover point (not from file) and then attach the file to the point.

I repeat my recommendation here as it can help to somebody else:
- open the project and delete DPOS session related to your rover points;
- also delete all base points what you have for the session;
- select rover point and go to menu -> "Recover Base Point" (it will create base point @rover_point_name);
- select the base point then go to menu -> "Attach GNSS file" and attach the reference station file to the base point;
- go to menu -> "Recover DPOS session";
 

Matt Johnson

Well-Known Member
5PLS
And the problem is related to manual start of base file recording which you had to do in current Release. But in the PreRelease the file recording starts automatically and the problem should disappear.

I still ran into this problem when trying to help a customer today. He used a LS base and the file recording started automatically. When we used "Create Base & DPOS from File" it created a base session but the base point had the wrong coordinates and no associated rover points. We had to use "Recover Base Point", "Attach GNSS file" and then "Recover DPOS session" for it to work properly. I can try to get the project if you need it.
 

Michael Stazhkov

Developer
JAVAD GNSS
I still ran into this problem when trying to help a customer today. He used a LS base and the file recording started automatically. When we used "Create Base & DPOS from File" it created a base session but the base point had the wrong coordinates and no associated rover points. We had to use "Recover Base Point", "Attach GNSS file" and then "Recover DPOS session" for it to work properly. I can try to get the project if you need it.
It is better to get the project.
 
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