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Reach RTK vs Piksi?

Posted by AJ152 on August 9, 2016 at 4:59pm

Hello,

I've been reading lots of forums and posts out there about RTK, affordable equipment like Reach RTK and Piksi, but Piksi seems it requires lots of configuration and according to some posts lots of things could go wrong, and as for the Reach RTK, and I haven't found much, in fact I haven't found any videos of people using them, they both claim to integrate with Pixhawk, but has anyone test them?, similar? or cheaper?, and specially on Rovers?

http://store.swiftnav.com/s.nl/it.A/id.4216/.f

http://diydrones.com/profiles/blogs/affordable-new-rtk-gps-designed-for-pixhawk-apm

https://emlid.com/shop/reach-rtk-kit/

3691312691?profile=original

I'm sorry if this question was already answered but I'm researching before buying anything.

Thanks.

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Tags: piksi, pixhawk, rtk, reach
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Replies

  • John Campen December 1, 2016 at 8:41am

    I have also been testing Reach and it seems I am in the same situation that out in the field it works ok sometimes,and then other times it doesn't. Last weekend I updated to the Beta 2.1 and this seem to be a big improvement, however it still has browser issues that need to be worked out. . I sat it out on my balcony and even though only had half sky view I got a good fix and strong 8-10 sat signals and got some very good cm accurate data. I more interested to use it for creating accurate GCPs rather than fix it to my UAV.

    On the forum I see people doing this and then post processing the data and they seem to get very good results.

    Im still keen to work with  it , but now I need something more easy and reliable in the field.  These following are a few others I am now looking at.

    http://www.tersus-gnss.com/collections/gnss-rtk-boards  Top of my list so far.

    http://www.drobit.es/  Pros no need for ground markers claims to be very accurate, Cons, very pricey USD8-9k.(Also I don't need a flying solution).

    https://www.kickstarter.com/projects/141973618/one-button-survey-ob...  Very interesting and would be top of my list expect it wont be available until April next year.

    http://v-map.net/about-v-map/  Just found this one this week and still studying it and seems quite good as well.

    This one from Trimble also seems interesting. http://www.catalyst.trimble.com/index.html

    This looks ok as well, however like everything in Australia, it expensive and just under 7k http://geomatics.com.au/

    One thing is for sure,is a new one pops up nearly every few weeks now and I am sure between now and 6 months time there will be some very good options avalaible and likely a much lower costs.

    Sriram said:

    what is the range of wi-fi ?

    can we connect it to internet for correction?

    what happens when drone fly out of rtk wifi range? Does the rover gps is used as static gps?

    Juan Diaz said:

    I bought an EMLID Reach Kit. Here is my experience so far.

    • Integration with Pixhawk is good. It does require some configuration and understanding how the system and differential positioning works. It took me a lot of reading through the forum and around a week.
    • Antenna positioning and the use of correct ground planes is key! Test it many times until you find the set-up with best coverage.
    • After that, it seems that connection through telemetry radio is not very reliable (the corrections have dropouts, which does not permit to obtain a stable RTK FIX). I have experienced this, and read about a lot of people with the same issue. Nobody found a definitive answer to this.
    • Correction link through Wifi works great, I am using this approach currently (because the project in which I am working allows it). Since the drone does not fly very far away from the GCS, I can establish a wifi network.
    • In my current set-up, I am not able to obtain a stable fix every time. Most of the time it is lost after take-off and never recovered. I am working on it, might be an issue with the wifi network (too long distance between base, router and rover.
    • The Forum is fairly active, so doubts and problems can be solved by other users or Emlid workers.
    • The developers seem to be still improving the solution, because I have gone through at least 3 updates of the SW. So I guess there is still margin for improvement.

    In conclusion, the technology looks great. When it works, its impressive (centimetre level accuracy). But there are many difficulties along the way. I still have not been able to solve all of them at the same time to have a reliable and stable solution every time. I am using it professionally, and still cannot rely on it. I am working on it though, I have hope!

    I would love to hear the experience from other users of Reach or Piksi!

  • Sriram October 19, 2016 at 9:14pm

    thank you... Tom

  • Tom October 19, 2016 at 7:12am

    Three options, depending on your skills and what you actually need.

    1. open lrs telemetry link --> http://www.itluxembourg.lu/site/ultimate-lrs-or-3dr-radio/

    2. lora serial connection --> http://www.libelium.com/development/waspmote/documentation/waspmote...

    3. post processing the sd logged data (connect serial logger to reach output)

    other options are possible but less viable.

    Ultimate LRS or 3DR radio ?
  • Sriram October 19, 2016 at 6:00am

    I seems that the corrections can be sent by internet "ntrip client"... do you how to do it? what are the pros and cons? 

  • Juan Diaz October 19, 2016 at 5:54am

    If you use Reach's internal wifi only I guess that the range should be really small because it does not have external antennas and the transmission power is probably very low. That is why we use a Wifi router with higher transmission power and a high-gain antenna. All my devices (laptop, smartphone, ...) and Reach modules connect to that network so they can all access the corrections and RTK solutions.

  • Pbreed October 19, 2016 at 5:54am

    I tried a lot of expensive commercial soutions about  5 years ago with a helicopter and a hovering rocket.

    None of the L1 only soutions were reliable and robust.

    I eventually spent the $ to get a L1.L2 trimble setup and it was both stable and reliable. The performance was amazing.

    I doubt ANY of the L1 only solutions willbe stable and robust. I look forward to the low cost dual frequency solutions... as I believe they will be a game changer.

  • Sriram October 19, 2016 at 5:49am

    thank you Juan Diaz...... So we need to have a separate WiFi module and antenna to send corrections? I thought it uses Reach's internal wifi.... 

  • Juan Diaz October 19, 2016 at 5:40am

    The range depends on many factors:

    I have an Alfa Network Router, which has 500mW of Transmission power and an omni-directional antenna (supposedly 12dB although I guess it has much less, the stock antenna was 5dB). With this set-up I have been able to maintain stable FIX even with the base 90m away from the Router, and the Rover about 200m away from the router.

    With a more powerful router and directive antennas you could have more range.

    If RTK link is lost, the Rover starts working in SINGLE mode, and it is just like regular GPS with SBAS. In any case, I use Reach as a secondary GPS for safety.


    Sriram said:

    what is the range of wi-fi ?

    can we connect it to internet for correction?

    what happens when drone fly out of rtk wifi range? Does the rover gps is used as static gps?

    Juan Diaz said:

    I bought an EMLID Reach Kit. Here is my experience so far.

    • Integration with Pixhawk is good. It does require some configuration and understanding how the system and differential positioning works. It took me a lot of reading through the forum and around a week.
    • Antenna positioning and the use of correct ground planes is key! Test it many times until you find the set-up with best coverage.
    • After that, it seems that connection through telemetry radio is not very reliable (the corrections have dropouts, which does not permit to obtain a stable RTK FIX). I have experienced this, and read about a lot of people with the same issue. Nobody found a definitive answer to this.
    • Correction link through Wifi works great, I am using this approach currently (because the project in which I am working allows it). Since the drone does not fly very far away from the GCS, I can establish a wifi network.
    • In my current set-up, I am not able to obtain a stable fix every time. Most of the time it is lost after take-off and never recovered. I am working on it, might be an issue with the wifi network (too long distance between base, router and rover.
    • The Forum is fairly active, so doubts and problems can be solved by other users or Emlid workers.
    • The developers seem to be still improving the solution, because I have gone through at least 3 updates of the SW. So I guess there is still margin for improvement.

    In conclusion, the technology looks great. When it works, its impressive (centimetre level accuracy). But there are many difficulties along the way. I still have not been able to solve all of them at the same time to have a reliable and stable solution every time. I am using it professionally, and still cannot rely on it. I am working on it though, I have hope!

    I would love to hear the experience from other users of Reach or Piksi!

  • Sriram October 19, 2016 at 5:32am


    How to calibrate sub cm precision in camera and gps ?

    Is there any procedure ?  
    Tom said:

    Shutter lag is always present in any camera. If you use autofocus and other metering (shoot full manual to avoid this) it even adds more delay from the trigger pulse to the actual taken photo. Without feedback you won't be able to measure the "exact" moment. A whole other story is to calibrate everything up to sub cm precision as x y z offset from camera sensor to gps antenna and ofc accurate acc data to measure the exact heading...

    too much for a "hobby grade" implementation IMHO.

  • Sriram October 19, 2016 at 5:23am

    what is the range of wi-fi ?

    can we connect it to internet for correction?

    what happens when drone fly out of rtk wifi range? Does the rover gps is used as static gps?

    Juan Diaz said:

    I bought an EMLID Reach Kit. Here is my experience so far.

    • Integration with Pixhawk is good. It does require some configuration and understanding how the system and differential positioning works. It took me a lot of reading through the forum and around a week.
    • Antenna positioning and the use of correct ground planes is key! Test it many times until you find the set-up with best coverage.
    • After that, it seems that connection through telemetry radio is not very reliable (the corrections have dropouts, which does not permit to obtain a stable RTK FIX). I have experienced this, and read about a lot of people with the same issue. Nobody found a definitive answer to this.
    • Correction link through Wifi works great, I am using this approach currently (because the project in which I am working allows it). Since the drone does not fly very far away from the GCS, I can establish a wifi network.
    • In my current set-up, I am not able to obtain a stable fix every time. Most of the time it is lost after take-off and never recovered. I am working on it, might be an issue with the wifi network (too long distance between base, router and rover.
    • The Forum is fairly active, so doubts and problems can be solved by other users or Emlid workers.
    • The developers seem to be still improving the solution, because I have gone through at least 3 updates of the SW. So I guess there is still margin for improvement.

    In conclusion, the technology looks great. When it works, its impressive (centimetre level accuracy). But there are many difficulties along the way. I still have not been able to solve all of them at the same time to have a reliable and stable solution every time. I am using it professionally, and still cannot rely on it. I am working on it though, I have hope!

    I would love to hear the experience from other users of Reach or Piksi!

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