Leica GS16 and L5 performance
Background: I wanted to do some rough field tests to analyze L5 and its improved performance. I have been using a GS 14 Leica GPS rover connected to SmartNet. At this time, SmartNet does not offer an L5 correction nor does my GS 14 receive the L5 correction. I had to upgrade.
I bought a Leica GS16 and installed a GR30 reference station creating my own private network. The GR 30 is set up for network correction and it is tracking L5. I set up the required Ntrip caster and it is broadcasting an RTCM V3 MMS 5 correction. With this modified RTCM signal the system can track L5. This is all done over the internet with a cell connection to the private network.
GR 30 Base Station
Here are a few of my initial findings: L5 works! I can get lock in extremely covered areas. I had 80% canopy coverage on a creek under privet hedge and could get lock. When tracking five of the L5 satellites, lock took approximately 2min. When I was tracking six it took 20 seconds. When I would move, I would lose lock, and it would be quickly reacquired. I could not get lock when I was completely obscured by heavy leaf vegetation like magnolias and privet bushes. I took multiple shots on the same point and accuracy ranged from 0.03’ to 0.10’ horizontally. These were just initial tests and were only inversed within the same job and the same data collector.
The negative for L5 is that only 12 out of the 32 U.S. satellites broadcast the more powerful L5 signal. Mission planning is required to take advantage of them. There is only a 30-min block of time where six satellites can be tracked. In figure 1 on the right there is a chart of all the existing GPS Satellites that are in orbit. Only the newer series, IIF, satellites broadcast the L5 signal.
In my test, there are many variables and this is by no means a scientific experiment. One of the biggest variables is that I have upgraded from a GS14 GPS receiver to a GS16 GPS receiver. My initial reaction is that L5 is amazing and it works much better; however, when I tracked just L1 and L2 using the new GS16 I could get lock in areas that the older system would not get lock in.
In conclusion, the L5 corrected signal seems to offer better performance in areas that would have been impossible to work in before, but the GS 16 receiver seems to be able to get lock in areas the older GS 14 could not lock on as well. It is hard to tell if the improved performance comes from the L5 signal or the more advanced GS16 GPS receiver. Whatever the case may be I am still a long way off from retiring my robotic total station.
Josh Lewis 4
I have just purchased a GR50 from Leica, and I am going to permanently set up my own reference station. I am not happy with the current subscription service that I am paying for. Despite what they say they are not broadcasting a Galileo or Beidou correction.
I am most interested in the Galileo GPS system because in 2018 they have launched 5 new satellites all transmitting the L5 correction. There is currently a race between the countries to outdo the US and the GPS system that we use. I predict that we will be able to get lock in full tree canopy.
I was wrong Smart Net is broadcasting Galileo correction. My GS 16 was not processing the correction because the firmware version I had (6.13.66) would not include it in the measurement calculation. I have since paid Leica’s ransom and updated to firmware 7.51. Galileo is now included in the correction.
10-05-2018…Still working on L5
OK, all this drama really is reduced down to Leica and their firmware. In retrospect, it is obvious now. Leica was not including L5 and Galileo in their measurement engine. You can verify this on your own unit when you would go to the satellite tracking and if the satellite is in parenthesis then it is not included in the measurement solution. I have just updated to their firmware version 8. It is even mentioned in the release notes that there is more information that is being processed from the Galileo system that was not being used before. Synopsis it works better in tree cover.
I think this ends my testing for L5 and differential GPS for a while. We are getting lock in heavily wood areas so it is possible. If you live in the Georgia area and would like to join our network contact me. I would love to create a private network. My base is in Chamblee GA.