Some time ago the idea was floated around about putting post-processing in an RTK controller so that points that were beyond the range of the base station corrections could be still be positioned by storing raw data, and processing in the field. I've never heard of any receiver/controller allowing for this feature. Saturday I had my first experience with post-processing in the field.
I was using a Javad Triumph-LS with a Javad Triumph-1 receiver as my base. I had the Triumph-1 broadcasting at very low power. I collected data on four points. The fourth point I collected twice. This gave me five collected points: L001-L005.
The first point (L001) received corrections producing a fixed solution. The remaining four points (L002-L005) were standalone. I sent the project to Javad's new DPOS server. This included sending the base station data and the rover data. The raw data from the collected points were processed with the base data. DPOS is a service Javad developed a couple of years ago and integrated into the LS software about a year ago. In the LS DPOS has been used to process the base raw data with CORS data and automatically shift a project from an autonomous derived position to a precise ITRF based position. In this case, I was processing immediately after collecting the five points and CORS data wasn't available, but the new DPOS server still processed the on site vectors.
My base position for this project is still based on an autonomous (standalone) position. I calculated a simple translation from the autonomous base position to the known coordinates of my base point, POST. I then applied this translation to all post-processed rover coordinate points returned from DPOS: L001, L002, L003, L004 and L005. I then compared the translated DPOS coordinates to my known coordinates for the monuments I tied in. The results are as follows in US Survey Feet (Base Line length and observation time in parenthesis):
L001 (69' 5 minute observation)
dN +0.0075
dE +0.0036
dU -0.0239
L002 (4825' 5 minute observation)
dN +0.0296
dE -0.0374
dU -0.0447
L003 (13560' 5 minute observation)
dN +0.0192
dE -0.0093
dU +0.0390
L004 (50102' 6 minute observation)
dN +0.0348
dE -0.0457
dU -0.0028
L005 (50102' 15 minute observation)
dN +0.0292
dE +0.0011
dU +0.0939
With comparisons like these, I would find it difficult to say that the Justin engine used by DPOS was in error. The controlling coordinates I'm comparing with could be this far from "truth". I would consider these results to be practically perfect. With this new capability, a user can locate a distant point without the concern for maintaining radio communication. Also, users will have the ability to choose between RTK or Post Processed vectors, using the other as an additional verification through a comparative check on results.
To my knowledge, no system has ever allowed for integrated post-processing. Other manufacturers have required the data be downloaded to $oftware on a PC for post-processing. Then the results of the post processing must be reintegrated into the database in some way. The LS still "downloads" but it's all very painless and automated, so there is a considerable time savings. Also, the download is "virtual" so you aren't downloading to a separate device. The post-processing is fully automatic and uses Javad's servers (so the processing overhead is minimized). The results are returned to the LS and integrated into the database automatically. No additional time spent doing this manually. And all without the need for additional $oftware on the PC. This translates to an ability to perform this process in the field with only the LS and the Javad base receiver. You can literally observe the rover points, return to the base, download the file (which is automatic), submit to DPOS (which is automated), and get the result back in the field with Internet access. It's almost RTK in that you get a precise answer in the field from a single device without range limitations. You'll notice that points L004 and L005 above are 9.5 miles from the base. Even if I only had a 1 watt modem, I can precisely locate this point with only a few minutes of data, while being out of range of the corrections. More to come...
Clarify above....
Flow chart it for somebody who has no mechanism for dpos, until later, ie you didn't make it super clear how this would work. Do you return to base, download the base file, process the base file, against the long range observation, and then restart the base, keep working, and then at the end of the day, dpos it, and it all shows up at the end of the day, on the same datum, With dpos?
I know post processed static CAN yield stronger solutions, than rtk.
Will there be a way to compare the pps observation, against the rtk position, in those "really bad holes" that I seem to "find"?
Ok, I re read it. It is dpos dependant.
Nate and All,
Let me describe this another way for visualization.
Saturday I set my base on a known point in the yard, and with the rover on a bipod collected an RTK point. I then turned off the corrections to my rover, and set my rover to accept points using no corrections. I then stored a dozen points. When I looked at the screen, I had points scattered across several feet as expected.
I walked back to the base, stopped the base which automatically transferred the base file to the LS. I then pressed the "DPOS" button on the LS, and my base file, and the short static files were all sent to the DPOS server in under a minute.
While I was still standing at the tripod after about 4 or 5 minutes, the LS let out a little bell sound. I then pressed the "Adjust" button.
I now have twelve points that are all within 0.02' of my initial RTK shot. That simple.
how do i access the files in the rover to send them to dpos ?
Randy,
Shawn and I are commenting upon the version which is still in testing. These features will be released soon. Once this is released, all associated base and rover files will be transmitted automatically. You will not need to hunt for them.
My description above sums it up rather well. It is so easy to accomplish, that it is difficult to accept. I am really looking forward to our next release.
Randy Rhodes, post: 359420, member: 10669 wrote: how do i access the files in the rover to send them to dpos ?
This is currently in testing and not ready for release.
Well that just destroyed a bright point in my day 🙂
Randy Rhodes, post: 359461, member: 10669 wrote: Well that just destroyed a bright point in my day 🙂
Randy, we spoke on the phone a couple of times a few months ago. It's good to see you posting on here, How is your new equipment workin' for ya up in the mountains?
Its doing well. Really better than i expected. Do any of you know when the update will be released ?
I'm waiting... drumming my fingers.... waiting.... BOOM! It will soon be be here.
Can't wait.
It comes with a bunch of other goodies.
Such as a bunch of pre-sets. Like, quick buttons, to change from 600 epochs, with verify, to lift and tilt, for start and stop. And, back again, quickly.
It's going to make it better.
Nate
Right now using a ToughPad loaded with Magnet Field and Magnet Tools I can post process the static data and rtk data in the field. Which is basically what you two are describing with this "new idea ... Hybrid RTK". Grant it I have to press a few buttons, and do some analysis, which I'd prefer anyway. Not sure I would like all the behind the scenes post processing being done by Javads website, then poof a website provides my corrected coordinates automatically in the receiver.
Can only imagine the excuses coming from this process Javad is working on.
such as:
"my Javad system made those corrections automatically, so it must be correct"
Well, Lee, all button pushing, can get messed up. If you post process, and some factor was omitted, such as HI, of the base, or a wrong HI, or a Wrong Height of rover.
I have been meddling with this pile for a while. I've made some assumptions, that turned out to be wrong. (The Javad Pile) I have a wish and want list. I want some things, that may never happen. I am aware that good ideas, sometimes turn out to be bad ideas, after applying them. Sometimes, somebody else applies things differently, than you did. And, then they become good ideas.
One of the items that seems to be a part of the Javad equation, is that IF you let your base sit and cook for a few hours, you can then upload it, and get your answer for that base back in a few minutes, IF you dpos it after GPS midnight.
The thing that's interesting, is you are ALSO going to get a DPOS answer, if you only have a 10 minute (20 epoch) observation. HOWEVER, the rover will ALSO be getting a DPOS, An independent OPUS) for this 10 minute observation. So, this will be supplying a sort of check. A 20 epoch session is not as good as a 4 hr session, but, it WILL provide an additional check on things.
It's value will vary, depending on the length of time, length of observation, and the constellation, of course. But, the DPOS thing, has "More in it than meets the eye".
IF you take a long range, (beyond radio) shot, on ANOTHER survey, that has a previous Javad shot on it, or, if it has previous coords on it, then you are going to have a Check on everything, AFTER you dpos the base coordinate, for that particular site. That is, a closed loop, from BASE to the nearby COORS stations, and the COORS to the ROVER, and then the BASE to ROVER differential position.
The way I see it, is the MORE baselines, then the more redundancy, and the more baseline checks are built in, the better the data.
My 2 cents.
Nate
Shawn Billings, post: 359028, member: 6521 wrote: Some time ago the idea was floated around about putting post-processing in an RTK controller so that points that were beyond the range of the base station corrections could be still be positioned by storing raw data, and processing in the field. I've never heard of any receiver/controller allowing for this feature. Saturday I had my first experience with post-processing in the field.
...More to come...
Some of the points are processed using your standalone base, and others using different CORS stations (cloud processing, like OPUS)?
I would prefer if it would process the data incorporating my base in some way. Is that an option as well?
Yes, your base data and your rover data, as well as up to five CORS stations are all incorporated.
Base - Rover vectors can be performed as I described above. To add CORS, you must wait until GPS midnight.
leegreen, post: 359482, member: 2332 wrote: Right now using a ToughPad loaded with Magnet Field and Magnet Tools I can post process the static data and rtk data in the field. Which is basically what you two are describing with this "new idea ... Hybrid RTK".
You are mostly correct, Lee. I've been reading about your use of tablets in the field and am truly impressed. It sounds like you're content with this arrangement and I won't try to talk you out of it. But I will say that the differences are more than a few button presses:
- You've worked around one of the usual differences in that you are using the same hardware that you are performing data collection on for your GNSS post processing. That's slick. Most users will not be doing this and will require a separate computer to do the processing. The separate computer must be carried in the field, the receivers must be downloaded into this extra separate computer. This extra computer also costs extra money. Like I said, you've alleviated a good portion of that.
- You have to have extra . What's a seat of Magnet Tools running these days? You have to know how to operate this software and you have to operate this software in field conditions.
- You have to merge the results from the extra back into the data collection software. Is it impossible? Of course not. And sense you have the two applications on the same device, you definitely save some effort compared to someone sending files from the separate laptop or tablet back to the data collector.
You like the control that using your own post processing affords you. I understand that. I really do. Most users don't want all of that though. They want an answer. Now Javad's display is going to provide some minimal statistics so that users have some assurance in the reliability of the results, including a comprehensive comparison of RTK vectors and post processed vectors when available. I don't believe that Hybrid RTK will ever fully replace post processing and network adjustment software.
Now, Shawn, that you bring that up...... the idea of a separate piece of hardware. I generally agree... no other hardware. It seems that many of the LS users, keep a laptop in the truck....
I want away from that.
I have some of the design in place, for THE magic field cogo.
I can lay it all out. It would take me about 2 wks of straight work, to write EACH page, and it's entire structure. Maybe more.
But, I HAVE that piece of the equation.
N
Shawn,
I really like the ideas Javad has brought to the hardware side of GNSS system, but the cogo routines, and lack of robotic/optical instruments collaboration is just NOT there. If we could combine the Javad GNSS hardware with the cogo and field applications of Magnet or Carlson, it would be a very efficient set of tools in the surveyors bag. I feel Topcon is getting behind in the hardware market of GNSS technology. When compared to other vendors, the GR-5 and Hiper V's are too heavy, too bulky, have no slope sensor, no camera, and lack of other features recently introduced to market. I was hoping [USER=8922]@pmoran[/USER] of Topcon would enlighten us on what Topcon may be doing in this area. I have always believed not one vendor will make a single best product, it takes others to push them and help us all advance in technology. There is not a single magic tool that can do it all, but a well equipment tool box with the a properly selected set of tools that with make us most efficient.
An example: Everyday I bounce between multiple software's such as Bentley InRoads and Carlson Takeoff on the same project, because I know one software has a more efficient routine for the task at hand. As these products mature and one vendor creates a new routine, we often see a similar routine adapted by the other vendors in future upgrades of their software and/or hardware. This is what I see Javad doing for today's market in GNSS.
I agree Lee. Free market competition has driven technology to improve at a tremendous pace. Like most people, I was kind of concerned with so many companies were being consolidated. It's good to see some diversity in the products. Competitors either have to figure out how to copy them or best them in some other way. In either case it's good for the consumer.
I've also cobbled together some fun combinations of software and hardware. Creative problem solving is one of the things I really like about surveying. You never know what challenge is around the next bend and what solution you'll need to pull out of your bag of tricks.
leegreen, post: 359482, member: 2332 wrote: Right now using a ToughPad loaded with Magnet Field and Magnet Tools I can post process the static data and rtk data in the field. Which is basically what you two are describing with this "new idea ... Hybrid RTK". Grant it I have to press a few buttons, and do some analysis, which I'd prefer anyway. Not sure I would like all the behind the scenes post processing being done by Javads website, then poof a website provides my corrected coordinates automatically in the receiver.
Can only imagine the excuses coming from this process Javad is working on.
such as:
"my Javad system made those corrections automatically, so it must be correct"
I'm not sure I follow. Why would you want to do analysis that the software can do for you much quicker? Once tested against other methods, and with resulting statistics shown in each instance, what more can you ask for? I don't remeasure every edm shot with a steel tape, and I don't reanalyze the satellite positions to see if the space/ground segment is correctly computing their positions, nor do I recalculate each label I put on a map with Carlson from the input coordinates. At some point we have to trust the technology (more and more these days). I'm sure there are some projects where performing your own post processing would be beneficial, but I think those instances are becoming fewer and fewer with the technology at hand. If I ran into a project like that I would send it to someone like yourself that already has the required software and knows how to use it. Not worth it to me to buy and learn another package for very occasional use (would have to relearn every time I wanted to use it).
But I agree, JAVAD is pushing the envelope and other manufacturers better pay attention. Kind of a truth of technology has been that no one (or very few) is successful in producing both hardware and software to go with it. JAVAD is making a very impressive run at it so far. I continue to believe the all in one model is the goal of the future that JAVAD is bringing to life now.
