How Do I Adjust Base Position?

As an exercise, I collected some points today using the T-LS to get a few minutes of network RTK for a base position, then swapped the T2 onto the tripod and switched over to UHF RTK. I also collected a static file with the T2, which I've since submitted to OPUS. How do I adjust/reprocess/whatever the UHF points using the OPUS position for the base?

If I had entered a bad HI for the T2 (which this evening I thought I had, until I remembered that only the OPUS submittal used a different HI because I specified the JAVTRIUMPH_2A antenna), could I correct for this as well after the fact?

Thanks!

This seems to be a recurring question.

With J-Field you can currently adjust the coordinate of the base and then recalculate the coordinates of all those points collected from that base coordinate.

To do this go to Points and choose a point surveyed from that Base position. Click the Edit button and then the information box containing the Antenna Height. It will then list the statistics for that point, click the Base button and then enter the adjusted position and click ok. You will be prompted if you want to correct all related surveyed points, choose yes and all your points will be updated using their vectors from the OPUS coordinate you entered.

Any calculated points or imported points in the database will NOT move with the change in base coordinates. This is reasonable since there is no connection between the base and a calculated point, but it should be understood and considered when using this technique.

Also, when changing the base coordinate, the default system you will be presented for the base coordinate will be WGS84/ITRF2008. You can change this to show any coordinate system in the library and then edit the coordinates.

The Antenna Height can't be adjusted yet. Being able to edit the base point in the Points screen and have it update and recalculate the related survey points is on the to do list so this process will be simpler and more straight forward in the future.

While we're on the subject of "simpler": some of my jobs are run in meters and some in feet, and every time I've made the switch I've had to scratch my head and wander through darn near every menu button before finding the place I can make it happen. I did it again yesterday, but right now I can't tell you where I found it. To me that suggests that it's not in a logical place; shouldn't something that basic be immediately available through the Setup button?

Jim Frame said:

While we're on the subject of "simpler": some of my jobs are run in meters and some in feet, and every time I've made the switch I've had to scratch my head and wander through darn near every menu button before finding the place I can make it happen. I did it again yesterday, but right now I can't tell you where I found it. To me that suggests that it's not in a logical place; shouldn't something that basic be immediately available through the Setup button?

Click to expand...

Jim, look at Setup>Advanced>Units

Most places where distances are asked for you can temporarily change units for that entry also.

Jim Frame said:

As an exercise, I collected some points today using the T-LS to get a few minutes of network RTK for a base position, then swapped the T2 onto the tripod and switched over to UHF RTK. I also collected a static file with the T2, which I've since submitted to OPUS. How do I adjust/reprocess/whatever the UHF points using the OPUS position for the base?

If I had entered a bad HI for the T2 (which this evening I thought I had, until I remembered that only the OPUS submittal used a different HI because I specified the JAVTRIUMPH_2A antenna), could I correct for this as well after the fact?

Thanks!

Click to expand...

Great suggestion. You've got me thinking about how that might look.

Matt Johnson said:

This seems to be a recurring question.
...

Click to expand...

Great answer Matt. This popular question and its answer ought be included in the Quick Start Guide that you're writing. BTW, when will that be done?

Yes I have already planned on including it in the Quick Start Guide that I am writing. My goal is to finish it by next Monday.

Excellent!

Shawn Billings said:

Great suggestion. You've got me thinking about how that might look.

Click to expand...

The ability to assign the Units action to one of the User buttons would be nice.

Currently Setup can be assigned as a button. From there, the unit settings are only 1 button press away.

Setup|Advanced|Units|[unit choice] looks more like 4 pushes before I get the desired result. A user-button units toggle would be a happier solution for me.

The User button "Setup"takes you directly into Advanced Settings. Are you wanting a button that toggles between US Survey Feet and Metric?

Matt Johnson said:

The User button "Setup"takes you directly into Advanced Settings. Are you wanting a button that toggles between US Survey Feet and Metric?

Click to expand...

I didn't realize that the User assignment of Setup went right to the Advanced Settings. While a user units toggle would be nice, I can make do with the Settings assignment.

The important thing for me is to mentally associate the Units setting with a particular top-level button press. Maybe it's just the reality of advancing old age, but trying to find the Units setting in the menus had me utterly stumped on at least 3 occasions. I knew it was in there, but I wasted a good 10 minutes each time trying to find it. I felt like I was lost in a maze, repeatedly ending up at the same collection of dead ends.

Thanks!

Matt Johnson said:

This seems to be a recurring question.

With J-Field you can currently adjust the coordinate of the base and then recalculate the coordinates of all those points collected from that base coordinate.

To do this go to Points and choose a point surveyed from that Base position. Click the edit button and then the button containing the Antenna Height. It will then list the statistics for that point, click the Base button and then enter the adjusted position and click ok. You will be prompted if you want to correct all related surveyed points, choose yes and all your points will be updated using their vectors from the OPUS coordinate you entered.

Any calculated points or imported points in the database will NOT move with the change in base coordinates. This is reasonable since there is no connection between the base and a calculated point, but it should be understood and considered when using this technique.

Also, when changing the base coordinate, the default system you will be presented for the base coordinate will be WGS84/ITRF2008. You can change this to show any coordinate system in the library and then edit the coordinates.

The Antenna Height can't be adjusted yet. Being able to edit the base point in the Points screen and have it update and recalculate the related survey points is on the to do list so this process will be simpler and more straight forward in the future.

Click to expand...

Hi Matt,

I did this and it's telling me the coordinate system is out of range...

how far are you trying to adjust the base position, Jim? and what coordinate system are you using?

Hi Shawn,

That reminds of something that happened in the field. I have upgraded J-field twice since (just prior to my last survey).

When I set up the base station yesterday I could not connect to the base via the LS. So, I attempted to transfer the setup through the second home screen menu. When I do this it asks for the Bluetooth code which has always been 1234. It didn't work yesterday, however the base was sending corrections to the rover. In fact, the new upgrade fixes much faster and in areas with more extensive tree coverage.

So, I guess the base thinks it's in the last position where I was able to set-up propertly. That is about 50 miles out and crossing one state plane zone...

I'm not exactly sure what you mean by "could not connect to base via the LS" and "I attempted to transfer the setup the second home screen menu". In what way were you unable to connect to base via the LS?

Regarding the base using a distant position:
The way the Triumph2 is generally configured, it will send corrections based on the last position it used when it was shut down. There is a setting in Netview to change this behavior to start with an autonomous position automatically, but this is not the default. So, yes, if you drive to a job today that is 50 miles from the job you did yesterday, it will broadcast the position from 50 miles away. If you connect the LS to the Triumph2 via Base/Rover Setup one of the items you will see displayed is the 2D delta, which is the epoch by epoch autonomous position of the base compared to the programed position of the base. If this 2D delta exceeds 10 meters, the message changes to say "Too Far" and will not allow you to Start the Base. This feature should prevent the user from starting the base with a really bad base position. It does not however, prevent the user from setting up the Triumph2 and modem (which will immediately continue broadcasting as it did when shut down) and the LS receiving those corrections. The safety valve here is in the Base/Rover setup.

To work with the new Base/Rover Setup, you need to connect the LS to the Triumph2 via Bluetooth first. I have no pin assigned to my Triumph2. If you have cleared the NVRAM in yours lately, it may have defaulted to not using a pin, too, even if you had one before. Once connected, check to see if the base is currently broadcasting either by looking at the modem Tx light or by looking to see if the LS says "Stop Base" (in which case the base is running) or "Start Base" (in which case it is not running). If the base is running press "Stop Base". Now you can edit the position, HI, and communications parameters as necessary. Once these settings have been sent (each requires an individual "Send to Base" if it has been edited), then press "Start Base". Once you have pressed Start Base, the icons and messages above the communications parameters will show you the progress of the radio modem connection.

Hi Shawn and Matt,

I haven't cleared the ram that I know of. Somehow the T2 password was changed. I changed it back and JMT connected. I did hit set default on the connection page of JMT. When I did this it may reset something. After that I started having a problem.

I will check the LS Bluetooth connection next. The Bluetooth password that's set in the paramaters screen in NetView is 1234...

Shawn: yes you are correct. I turned it all on and it connected.

Can I just delete the password in NetView for Bluetooth?

The data when plotted on an image in state plan coordinates, the points appear to be shifted by about 6 ft in the x and y directions (even though the base coordinates are off by 50 miles).

Shawn Billings said:

how far are you trying to adjust the base position, Jim? and what coordinate system are you using?

Click to expand...

I don't know yet about the base adjustment -- I haven't gotten around to looking at the data -- but I want to see how a 10 km single-base CA RTN position compares with an OPUS position, particularly the vertical. Both systems are nominally NAD83(2011) epoch 2010.0 and NAVD88, as I recall. This is still just an experiment, though it's in preparation for an Elevation Certificate project I've got coming up.

Jim Campi said:

Hi Shawn and Matt,
Can I just delete the password in NetView for Bluetooth?

The data when plotted on an image in state plan coordinates, the points appear to be shifted by about 6 ft in the x and y directions (even though the base coordinates are off by 50 miles).

Click to expand...

I checked mine again and it is set to 0000 for the pin. I misspoke. You have to have a pin.

I don't see any way possible for you to have rover points that are six feet off and a base point that is 50 miles off. Can you post a screen capture of the base rover statistics screen from one of your surveyed points? Go to Points>[highlight a point]>Press Edit button (pencil)>Press middle left button (shows epoch count) and the screen should show the base rover statistics screen that will show your base station coordinates, along with many statistics related to your surveyed points. It would answer a lot of questions.