Tuesdays Tip - Average GPS Points in Trimble Access

In this tip I am going to show you have to average points in Trimble Access by using the same point number.

[@4815162342SW]

Great video Robert, I have always used the average point tool in Access to measure control points. However I met the very issue you explained regarding the locked coordinate in TBC when i processed the base coordinate. Thanks for the info!

[@vyacheslavkostromin]

Hi Rovert. Am I right that in TSC 3 I cant ad to the favourints "RTK initialization" for example? There is just a list of some command just.

[@dgmanon]

Thanks for the info, I always encourage the use of double observing CP and points you plan on Calibrating to in order to know the GPS is coming up with a good position. It is our States DOT standard to measure CP at least twice in the AM for a total of 120 epochs (a SET) then 4-8 hrs later at least twice for a total of 120 epochs, averaging all shots (sets) together, if any 1 point is out of spec the Set must be measured again at a different time to achieve a good CP

[@SurveyingWithRobert]

If you could run two base stations and pull two vectors would that help your workflow?

[@dgmanon]

@@SurveyingWithRobert WisCORS uses multiple base stations to figure positioning but only the closest one shows up in your survey. However I always seem to be working on the edge of the network which causes oddities in data. I feel it is good field procedure to double shoot control and if possible at different times (hours appart) using different constellations or satellites to determine a position. I must follow state DOT guidelines when doing work for them so until they change procedures i must observe CP for 120 epoch over a minimum of 2 shots and then observe 120 epoch again with a differant satellite constellation, averaging all shots

[@geoterminus6040]

DeWayne Manon, Can you please teach me how you average two points in Cogo? As Robert was illustrating it will ask for average when you are out of tolerance set in style. But it will store point with out giving the opportunity to average or overwrite if you are within quality tolerance. So you have to average them in cogo. But when I go there it ask me for point number again and again. I know I am doing it wrong. Could you please tell me how should I do it?

[@dgmanon]

@@geoterminus6040 Trimble Access < General Survey < Measure Points : Measure point 1 (observation stored), Change the point number to 1 (hit OK I know this point already exists) and measure again, when the required epochs have been reached it should ask to Average, overright, store another, ect. chose Average and you are done. It will display a screen showing how far it has moved the point from the first measured shot or the average point if you have measured it more than twice. NO NEED TO GO TO COGO. you can measure points multiple times and compute averages this way. I measure a point 9 times this week like this. If you measured the same point as point number 1 and number 2 you need to rename them the same point number and go to COGO , Compute average. type in the point you want to average (lets call it 2) and hit compute or OK (whatever it says in the bottom right) it will compute the average of all the undeleted points named 2. here is the problem with COGO If there is already an averaged point it will use the average along with the measured to compute the location. one more thing all my collectors are setup as a weighted average so it takes into account Other stuff when computing the average so you cant do a normal average and expect it to be the same number. Hope that helps

[@geoterminus6040]

DeWayne Manon REALLY appreciate your prompt and we’ll explained reply. I just figured out. I had trouble doing it in cogo. I was doing it the way you said but Our Survey style is set the way which it will store point even it they are the same number if those two shots are less the hundredth. So you will not see the prompt to average or overwrite or another. That’s why I was trying to average them in cogo even they were within the quality we set in Survey style. Since I was in field I just revisited cogo and was able to average them in cogo It was funny because it was so easy I don’t know what I was doing last time. Anyhow, really appreciate your time you took to explain.

[@vyacheslavkostromin]

As Rober Hoy mentioned already, why do you prefer to reset satelites instead of RTK?

[@roberthoy9163]

I use "reset rtk initialization" as recommended by Trimble technical support. Resetting satellite tracking is unnecessary and potentially time costly if you are in the trees.

[@vyacheslavkostromin]

What is the difference in time ?