Anyone familiar with satellite hot spots for data only? Recently tried a satellite based GPS correction service and it worked, but does not hold a solution well and takes too long to converge.
Have a lot of work in areas of limited to no cell service. This linear work is only for utility locating purposes, that I would like to utilize a CORs/network based GPS corrections service if at all possible.
Thank you!
I and at least one other member here are using the Inmarsat iSavi, beware that data is NOT inexpensive though, works good for getting discrete?ÿpoints in areas without cell coverage BUT within the bounds of a RTN. I don't think it would be practical for topo due to airtime costs. If working small areas, you can get a RTN position for a base station then run your own corrections locally.
This took a bit of roll your own ingenuity to get working with our IT folks as there is some networking knowledge needed (at least for the way we implemented).
SHG
Trimble RTX (subscription based) will work nearly anywhere. The only restrictions are far north and south latitudes due to beam coverage from the geosynchronous communications satellites.?ÿ?ÿ
I and at least one other member here are using the Inmarsat iSavi, beware that data is NOT inexpensive though, works good for getting discrete?ÿpoints in areas without cell coverage BUT within the bounds of a RTN. I don't think it would be practical for topo due to airtime costs. If working small areas, you can get a RTN position for a base station then run your own corrections locally.
This took a bit of roll your own ingenuity to get working with our IT folks as there is some networking knowledge needed (at least for the way we implemented).
SHG
Thanks Shelby, I was looking at the?ÿGlobalstar Sat-Fi2 unit. Have been waiting on accounting to get me a couple months worth of invoices for our sim cards we use to get an idea how much data is used for internet bridges and RTN. Wasn't sure if there is a delay or speed issue with utilizing satellite hot spots that would cause an issue?
The scale of this work is quite large, so there is some room to find the best method. We had previously OPUS'd control and used a 35 watt radio to get to a lot of these areas, just a lot of shuffling.
Trimble RTX (subscription based) will work nearly anywhere. The only restrictions are far north and south latitudes due to beam coverage from the geosynchronous communications satellites.?ÿ?ÿ
We happen to use Carlson GPS units (BRx5's and BRx6's) that are produced by Hemisphere. They have an Atlas service, which I believe is similar to the Trimble RTX. This worked great (could take 25 minutes to converge), but once we were in a chocked 40' ROW with adjacent trees, we would have to wait to re-converge for each shot (100' intervals +/-).
Currently going to back to the 35 Watt radio...
Technically it works, no appreciable latency. ALL of the data satellites require DIRECT CLEAR line of sight to the respective satellite, so sometimes the data terminal is positioned a bit away from the rover, but within short distance communication range such as you would have with WiFi or Bluetooth or short distance radio links.
Depending on your GNSS hardware will determine how all the parts of the system are setup. We have older receivers without WiFi, so the least expensive way to go for us (because of already owned hardware) was via WiFi from the satellite terminal (we already owned for field comms from remote locations) to a portable router and then via Ethernet cable to an Intuicom bridge (we already owned) and then over 900 Mhz to the rover. Essentially we changed ONLY how the Intuicom bridge received internet data and nothing on the rover, added the inexpensive travel router as the only new piece of hardware to what we already owned.
The kind of cool piece to this is I have also replaced the satellite terminal with a burner cellular hotspot (if I want to temporarily use a different cell carrier) and the rest works the same, so very flexible solution.
There are three satellite data solutions in North America; Iridium, Inmarsat and GlobalStar. Inmarsat uses geostationary satellites the other two do not. Each system has advantages and disadvantages , so research what works best for you.
Once you get past the price of entry for hardware, the real cost is the ongoing airtime, with Inmarsat that is $3.95 per Mb plus an annual fee of $240 that provides basically no data. You have to evaluate whether the increased costs will be helpful to the bottom line in your operation considering labor of alternate methods. If your area has a wide coverage RTN but sketchy cell networks, then the answer may be yes depending on how much time it saves shagging radio repeaters, your own base station, etc.
Link to the vendor we used for hardware, they know nothing of how we made the work for GNSS RTN, but lots of info on their website.
https://www.ocens.com/index.html
SHG
We use a mifi units with antenna jacks and then port those to a variety of antennas.?ÿ We really rarely use one stronger than 4 dBi.?ÿ We have found one hole that nothing would work in, but, for us one static or rtk location in 3 years isn't that bad.?ÿ That one hole could have been a bad fitting that was found later as well.?ÿ Thread on mounts
Shelby & Norm, you guys are much smarter than me!
I may try an antenna or two first, they are fairly reasonably priced before making a commitment into something that may cost me $5k for this project.
Thank you!!
