Your resident s/Surveying sleuthing geologist here…
I am looking at purchasing an Emlid Reach RS2. The price seems almost too good to be true… What are your criticisms, critques, and praises? What are the advantages of the Topcon and Trimble RTK rovers??
I am planning to use it without a second unit, using only the local NTRIP. Based on my research it sounds that the NTRIP should be as accurate, or even more accurante(?), than using a single local base station. It will have two primary uses within our daily activities: A) Provide GCPs for our P4 RTK, and B) Give us some idea of control/location on large grading jobs when we are doing remedial grading.
You can’t imagine how often we heard this I think I’ll leave critiques and praises to our users, but want to comment on the accuracy and applications.
There is no difference in accuracy between NTRIP and your own base. What really affects the accuracy is a baseline. For Reach RS2, the maximum baseline is 60 km in RTK. So, if you want to use the NTRIP service, pay attention to this.
Another thing is that NTRIP will always give you absolute accuracy. You don’t need to worry about finding the known point on your survey site.
What you are paying for with Topcon, Trimble and Leica is the their cost of their software ecosystem. There are many integrations with other softwares as well as machine control which is pretty limited with Emlid unless you are willing to do some technical work and purchase 3rd party equipment.
We have been running the RS2 corrections via NTRIP for about a year now and have very rarely gotten out into areas where either cellular service is unavailable or the CORS is too far away. That said Texas is a pretty big state so our network is a little sparse in comparison to what smaller states have and our network is not free but the $2k a year we pay is paid for in about 3 months by cutting base station management alone. Everything else is icing on the cake.
As far as accuracy there is really no difference except for the fact that you either have to have a known point or do some work to get a base point. NTRIP is turned on and you just go within about 5 minutes.
We also use the RS2 as a rover for GCPs and occasionally site stakeout but we have survey crews that do all the layout. We just check in with the Superintendent and help out if needed. For providing corrections to an RTK drone NTRIP is the way to go as well. The alternative is to cast a local base station which I believe people are having trouble with on the DJI products.
Last thing i’ll say is that because we do stakeout and sometimes need the project CAD linework we had to go with a more capable software so we chose MicroSurvey Fieldgenius for Android. It also allows for localization (calibration) of jobsites which is common in construction because there are always points that don’t match the CAD/Plat within our tolerances so the localization prorates all that error as a network.
For the $$$ they are hard to out do! I haven’t messed with Topcon much but have a lot of experience with Trimble.
The RS2 is pretty much plug and play when using NTRIP. It has a built in NTRIP client to connect to your service.
I love the versatility of outputting NMEA data (Serial/Bluetooth/USB).
I haven’t had an issue yet (mine is just about 1.5 years old now) but, I am curious after time when the internal batteries go bad, how you get them replaced. My recommendation would be have a battery door that has a replaceable battery. All batteries fail at some point.
I do like the feature of powering via the Lemo connector with serial out of it as well. I made a cable to connect it to my Trimble FMX which (when enabled) turns the unit on/off and supplies power to it. This is also being ported into my FMX as an additional GPS source. Due to Trimble proprietary stuff, it cannot be used for the AutoPilot steering but, it can be used for other applications in the monitor like automatic grade control of machinery.
It would definitely be nice to be able to replace a battery on the fly. Topcon Hiper +'s were internal and they then had removable batteries in the Hiper II and V’s then got rid of it again on the HR and VR’s. We don’t need the batteries for base stations since we started using solar battery power stations but rovers are obviously a different story. I know the batteries are expensive which is why we moved to the power stations because they (60k mah) are the same price as one small (6k mah) Topcon battery.
I believe that removable batteries for receivers are quite useful. However, such an option is closely related to the internal structure of the receiver. As Reach RS2 wasn’t designed to support something like this, we can hardly change it.