Access Question – Reset RTK
I saw this (RTK reset) mentioned in the integrated surveying thread the other day and it reminded me of a question I had.
So when I set a control point I typically shoot it once for 1-2 minutes, dump the rod, rotate the rod 180 and shoot it again for 1-2 minutes and average. I was informed that “dumping the rod” is the old school way of doing it, and the right way to reacquire the satellites is by reset RTK or reset SV tracking. What I’m wondering is what the difference is between these settings? I’ve been using reset RTK between my shots lately but I wonder is reset SV tracking is better for some reason.
A Trimble page I found regarding this isn’t particularly helpful, imo. RTK initialization (trimblegeospatial.com)
- 21 Replies
To add to your question…when I reset rtk by way of menu>measure>rtk initialization>reset rtk (because the reset rtk is removed from the satellites screen if e- bubble is disabled) it seems to regain a full lock with good numbers almost instantly, despite me seeing it go auton for a split second. I’m used to having to wait at least a few seconds before I can start shooting again, so it makes me wonder if resetting it in this menu, with e bubble disabled is actually doing the same full reset, as what I was doing before (or covering the receiver/dumping the rod) would do, or if it could make any difference at all.
this is the new way.
dumping the antenna like we used to do is old school old tech.
anyone promoting that old way with the new gear isn’t doing it right.
if you don’t believe the software and the hardware work together then put down the GPS and grab the transits the chains and the tapes and get back to work.
Get off off my lawn…
Ok let me splainit fur ya. In the old day we turned receiver upside down to force it to reinitialize. This only ck??s the last init to the new init. In technical terms interger ambiguity resolution has been solved twice and they seem to ck with each other. Also in the old day we would set the elevation mask so that no satellites could be tracked. This would clear all locked satellite data and once we dropped it back to 15 degrees it would have to re compute everything and intilazation. Now if you reset initial rtk its same as dumping. If you re set sv tracking it has to rebaquire all svs then it can re init. The latter should theoretically take a smidgen longer. But give you better assurance. But these things track and lock so fast these days we can barely see it.
now shooting a point same point withen less than a half hour of its self is only given you a warm fuzzy you did not have a bad initialization. It can happen but it is less likely these days vs the old days. If you want to average to have a better position more accurate. Then you should depending if its base and rover or network solutions allow an hour to pass by. 4 hours gives you a totally new constellation period. 2 hours a partial new satellites coming in old going out. 1 hour just allows for the change in geometry a little bit some new yes . Now that is gps only i am referring to. In wide open and say base and rober 1 hour is sufficient most of the time. NGS RTK guidelines By William Henning addresses this very topic it is for older equipment but is a great way to base the why you are doing what you are doing is and how to achieve X accuracy etc. there are 2 version of that document. I believe the latest was dated 2014.
in a hostile environment I would be pushing for the 4 hours gap . I would depend on site conditions shoot a point re set rtk init shoot again come back 4 hrs later do same in hostile this gives me the ability to have a new constellation and ck for a bad initialization. If the 4 hour gap shots are not usually withen the same few hundreths of your back to back spreads. But if you want to see something that helps you understand. Do a shot every hour for 24 hours. On same point. Good sky. If you then average all and compare to the same ever two and every 4 you will even though the deltas are further a part be closer to truth. If my old brain kicks in there is a study similar to this out there .
Oregon DOT put out a recent study that saw no clear increase in horizontal accuracy with repeat observations at a 1, 2, and 3 hr intervals. Vertical was better at 2 hours but vertical did not improve between 2 and 3 hours.
Usually I’ll be leaving for a different job by 4 hours later. But I could definitely set some control at my house, with averaged points shot once a day, just for experimentation sake.
I will sometimes try to take a couple of averaged shots and move on to something else nearby then reshoot once I’ve finished other work. Usually it’s only like half an hour but I feel like it’s better than nothing.
In the early days of GPS’ing we would do something called “mission planning”, which included “site charting” to insure that we could pick up 5 satellites at a given location and time. It wasn’t always a given, not by a long shot. Even when you could get 5 they maybe weren’t spread out to give you good PDOP. And the software wasn’t nearly as capable as todays. So things like “dumping the solution” were wise precautions to take.
Today, with 12-15 satellites at all times even from obstructed sites, and software that constantly acquires redundant integer solutions every second, dumping the solution is a quant relic of a bygone era. 1995 called, they want their data collection work flow back.
I do approve of rotating the rod 180?ø and remeasuring. It shows that the rod is true and plumb. But with the advent of tilt sensors that may go away one day soon also.
@said-lot of as that for rtk or static. And was it gps only or all constellations. I might need to see how it is now. I mean we get 30 plus sats in a solution now. The gps constellation in full force u will never see all of them at one time. So that changes things. But gps only I would say depends. Theres a reason that PPP positions no base only one reciever tracks the length of time it does for a position.
…but with the advent of tilt sensors that may go away one day soon also.
The 180?ø check still good for meaning out the runout in pole or worse someone if someone has bent it and kept quiet!
@olemanriver That was a study based on traditional GNSS survey control and Network RTK solutions on the Oregon reference network. I would guess at least GPS+GLONASS at most stations, additional constellations at the newest.
https://www.oregon.gov/odot/Programs/ResearchDocuments/SPR304-821_UpdatedSurveyStds.pdf
@said-lot thank you for the links. I will read this for sure. It is always good to read multiple studies for sure.
@norman-oklahoma so true. I still do a little planning and give the crews a heads up to what time a day will be worse. But also back then when we were not doing static fast static or PPK. We knew of no such thing as OTF on the fly initialazation. We had to get initialized on a known point. I remember when Trimble sent us the upgrade to get a 4800 to do on the fly initialization. Oh man that was better than p nut butter and jelly. Lol. I use to keep goof tees in my pocket so every so often on a big topo I would set me one and right the number down in my shirt pocket field book. So if i lost initialization i could go back and not have to walk so far. I pictured it back then compared to today as back then we walked as if we had a full cup of hot coffee and did not want to spill it with a rover. Now we have an enclosed bottle no spill so we can run lol ????
Reset satellite tracking clears any lingering satellite data and is quicker to do.
Unfortunately I don’t think our job scheduling issues make mission planning very feasible. The most I see is one crew say to another “our GPS was nfg today, how about yours?”
Walking with the GPS I have a habit of keeping it almost perfectly upright to prevent losing a lock, but I picked up that habit years ago. Same with walking with the prism and trying to keep a lock.
My occasional helper still doesn’t listen to me about holding the prism upright, he throws it over his shoulder and then loses his lock. I keep telling him “it’s not the Leica! Lose your lock and it’s a lot of screwing around to get it back LOL.
Right, I’m aware of the 4-hour window. I’m a bit more concerned about the bad initialization because it seems to pop up at the most unexpected times– like the middle of a wide open potato field.
Reset satellite tracking clears any lingering satellite data and is quicker to do.
@350rocketmike it is amazing how muscle memory works. Doing the same thing over and over again. Yeah probably not to many folks do mission planning much anymore. Some folks say doing it daily is to much of a hassle. But you can plan week ahead easily for each day. When I was in Georgia the sister company took my advice and the surveyor managers or field crew coordinators new just about every location that their crews would be for the week. And he just saved all the locations not point specific but site locations and bam he printed the daily out for the week and placed them in the field folder and also on the wall. Only time that might not work is if something changes last minute from a NANU report. But i showed them how to get the emails sent to them automatically. But reality is unless your going to push it into some spots that you know are going to be a problem and don??t want to waste time and do an obstruction chart and really find the best possible times it??s not as necessary today.
I’ve been told flipping the receiver no longer works with newer models.
Use the procedure outlined in the manual, that’s what works, so I’m told.
However, it’s very, very rare that there are bad fixes in open ground, something that was at least a daily occurrence back in my beta testing days. In heavy canopy you need to use it differently.
Today’s receivers are insanely sophisticated and versatile. They can do almost anything, just let them do the work.
Think of the way points were done back in the day, then shift your thinking to make it happen now. Use first principles to guide you.
Yeah I imagine it would be a very worthwhile system to implement, to help ensure good information on each job, if you could reliably implement it, but my experience is that the schedule changes several times a week…jobs get switched to a different day on the regular because someone isn’t ready (construction) etc. at least where I work this is the usual.
@bstrand yeah if I remember correctly the R8 runs a forward and backwards init ck it takes a little while for it to figure out if it is a bad init. So say you get init by truck as your getting ready to work and you walk a 100 ft in wide open observe and dump and it re inits and you see the first was bad Thats why. So a good practice with those and older equipment is get your gear on and as you are walking make it re init when you are in open sky. Not next to truck or building or stop sign or chainlink fence pine trees etc. also on those older recievers if you are init walking into a point thats good and you re init after. But if you get to a point and it inits while your at the point. On your second observation change the environment to get initialized in walk the other direction. Multipath is a slippery slimey pig. But its not the same every where so changes to your environment is a decent easy field procedures especially when you are pushing it. I have no idea how long you have been doing work so don??t take offense. But one of the best things that us old timers learned is we had to use a compass and clinomoter to do obstruction charts. Take that if you are new and hang it around your neck for a week or so. While you are collecting for 180 epochs kinda map out the satellites at your 10 or 15 degree elevation mask from your list that gives you azimuth and elevation. You will learn over time the. With your naked eye what is and what is not an obstruction. I can??t count the times when we built the network i. Georgia people saying its out a foot a half a foot blah blah blah. I would meet the crew chief on site and of course it was wide open. Wide open until i handed him a clinometer and compass and then that clear sky above him became much smaller. One is now licensed and we chat once in a while still. He runs his own company and he gives every new chief and i man a little training lesson on that.
@350rocketmike I hear you. When my boss sais we don??t have time to plan. I say my little ditty I heard years ago. Failing to plan is planning to fail. And my 7P??s prior proper planning prevents piss poor performance lol. But yes jobs sites change on construction. But if you know of every site location you can still plan even if you don??t go to it or not. The constellation will not change that much in a week or two day to day. You probably already know at say 330 it??s iffy or 430 etc.
We always found it worked best in the morning. Haven’t really noticed that lately as much though.
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