When performing some testing recently, I have found some interesting results and would like some opinions.
We are currently utilizing two REACH units. One on the UAV and one on the ground. They are then post-processed together using the EMLID version of RTKLIB to get the final positions. We have been getting great results, but there are times where the flight path doesn’t have the majority of the positions in fixed (or Q=1). They are only float (or Q=2).
However, we have recently been using an X90-OPUS receiver on the ground (for various reasons), instead of the REACH unit. When post-processing this unit with the REACH on the UAV, we have been getting 95%+ always fixed (or Q=1). My theory is that the X90 uses a better antenna. Please correct me if I’m wrong.
This leads me to the conclusion of wanting to try out some different (better) antennae for the ground unit with the REACH. I have done some researching and it doesn’t appear that anyone has recent test results for the best ground antenna to use with the REACH for the best fixed solution for post-processing.
Which antenna would be best for use on the ground with the REACH? Mainly for getting the best fix with the standard Tallysman Antenna that comes with the REACH, as this will still be used on the UAV due to its small size and weight. However, on the ground, it doesn’t matter if the size and weight are greater.
Thanks!
Steve
UPDATE: We have done some additional testing. When post-processing with RTKLIB to an NGS CORS station, using L1 ONLY and that stock antenna, we get a fixed position (Q=1) at a much higher percentage than when processing between two REACH units with the stock antenna. The baseline from REACH to CORS was 3 miles and the baseline between the two REACH was 1 mile. We are ordering a TW3710 Antenna, as suggested by Allen Crawford of Tallysman. Once that arrives we will do more testing and post back results.
For the Reach antenna I contacted Tallysman directly and for L1 they said their best antenna is the TW3740. Its super heavy compared to what comes with the Reach which for my rover application and for a base station worked great.
I was getting excellent signals during heavy cloud which empirically was an improvement.
I did not contact tallysman but i can confirm @mr337 tw3740 works really great - of course you need unobstructed view of sky; 3742 has an additional filter - i don’t have it (it may be better) but I am getting great results from tw3740 and i can also confirm its great; I do believe it does almost always make sense to buy the radome version because of rain or snow - its just a little bigger; considering the price it is really good - but if price doesn’t matter you may look into some leica antennas…
Hi,
isn’t the x90 a L1/L2-receiver? If that’s the case, it is not comparable with Reach, that does only L1. A L1/L2-receiver gives always better results, but the price is also not comparable. The game is about getting good results with a affordable device for most people here. Especially on a copter (flyaway, crash).
I’m using the TW3710 with Reach on the ground. Signals are slightly improved compared with the standard antenna and it looks great
@dirkkoller Yes, it’s an L1/L2-receiver. But, I don’t think you understand my setup. I’m only using the L1 signals from the X90 for processing directly with the REACH. There is a REACH on the UAV and an X90 on the ground. Processed together using only L1.
Swapping a REACH for the X90 on the ground and it doesn’t obtain a fixed solution as often. I’m guessing it’s only because of the antenna difference since I’m only processing the L1 signals for both setups.
@mr337 Are you getting more consistent fixes with the TW3740 compared with the stock antenna?
@panky Have you noticed more consistent fixes with your TW3740 compared with the stock antenna?
I found I was able to get a very solid Fix using a larger antenna than the kit antenna.
A dealer for the TW3740 antennas told me that the TW2705 antenna is the same antenna that is inside the TW3740 case and it is the same weight as the Reach’s kit antenna, 34g. You would have to cover the antenna with a wide piece of tape to hold it in place on a UAV but for the base station just buy a TW3740.
@cczeets When I was using the reach, the newer antenna made a huge difference in signal quality. I was getting fixes during very cloud skies. With the old antenna, if I looked at it wrong it seemed to throw it off I would highly recommend getting a better antenna that suits your application.
The Harxon antenna is a helical RTK GNSS antenna and by designed it can receive a good signal in almost any position. If your UAV tilts aggressively you might find it is a better choice than the antennas talked about in this thread.
The Reach user will likely have the ability to use the Galileo constellation in the near future so buying an antenna that supports Galileo might be a better choice now that more satellites are deployed.
If the Reach developers implement code for use of the Reach’s IMU and code for using the Galileo constellation you could have more satellites and a higher updata rate.
I would highly recommend getting a better antenna that suits your application.