$50 Skytraq RTK receiver has anyone used it?

@jedilord I plan on testing injection via mission planner next. I will probably get it wired up tomorrow, I just wanted to make sure it was actually working first.

I have looked at their other modules and the NS-HP-GN2 PX1122R was only 99usd compared to the 50usd for this one, but I wanted to see if the cheapest one they sold was actually usable for ardurover, if It’s not then the 99usd l1/l2 module will be the next one I test.

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Thank you.

If nothing else, this might be a cheaper fixed base implementation than using an F9P.

I’m using GPS for Yaw so I have two F9Ps on the rover, and currently a third for the fixed base - it seemed a waste at the time, but it was the cheapest L1/L2 receiver I could find that did RAW (or actually calculates the RTCM messages from a provided fixed position)

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I have been looking at mounting options for the antenna, I need to be able to move it to the side to clear the solar panel. Turns out gopro mounts are ideal for mounting gps antennas, you just need a thread adapter to change the 5/8 to a 1/4 thread to use the big antennas or just glue a smaller one to a GoPro thread adapter with the insert removed.

The plastic arm is quite flexible so if your going offroad the carbon or aluminium arms would be better. This GPS doesnt have a compass so im going to get a double gopro adapter and mount both to the arm.


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Hey @geofrancis,

I’m also interested in testing out these cheap SkyTraq RTK receivers. Quick question since you have one on hand, Is the SMA connection on the PCB normal or reverse polarity and is it male or female?

Thanks

Its an SMA connector, without the pin.

Thanks for the quick reply.

Just want to make sure they didn’t do something weird and add what’s known as a reverse polarity connector on the board. Which of these is it?

Edit: I guess by process of elimination it’s #2 since you said no pin and the pictures on navspark show the male threads.

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I’m interested if you get it working and if you are getting close to centimeter accuracy. I looked at ordering one too and shipping was $60 to the states so I balked. If it works, I might order 2 for a L1/L5 basestation since I am pushing the limits of the free ntrip provider. I think they would be more popular without 60 bucks for shipping.

That is the only place I have seen L1/L5 and centimeter accuracy without the L2. In fact I was going to make a post and ask if it was even possible because my google-fu is failing, and it seems like L5 would be better for a mowbot with the trees.

Long story short i managed to damage my receiver when a ground wire came loose on the 3.3v regulator when i was testing it on breadboard and it got pulled up to 5v killing it. Im going to order another 2 soon since shipping is so high i might as well.

It was qorking up until that point, i never got testing rtcm injection, it got broken as i was wiring it up.

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Oh, I’m sorry!! Im a little surprised 5v killed it to be honest.

You MIGHT want to order 1 for a basestation as well.

In short, the first chart says you need 2 for heading information for a rover.

"Most RTK correction service worldwide are still L1/L2 type, so L1/L2 RTK receivers work best with 3rd party RTK correction service without compatibility issues.

Only common signals used by both RTK base and RTK rover are used for RTK computation."

Which then the chart says it even if the rtk base supports L1/L2, the 1125 ignores the L2 data completely.

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Yes it can do rtk with just l1 its just not as reliable. I wanted to see if a 50usd GPS with free rtcm would work as the cheapest possible setup. Im not doing anything critical so I dont mind some trial and error getting it working.

It isn’t as accurate or reliable. For 50 bucks you -might- be able to get two l1/l5 receivers and try to set up a basestation for rtk. Then you have the l5 signals. Butt hen you need another antenna.

I am kind of in the same boat doing about the same thing except I want 1cm accuracy and my rtcm streamer is right about at the limit for it to work properly.

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PX1172RH-HAT looks like a good choice for RTK and YAW in one package for ~$200. Cheaper and more compact than two ArduSimple boards, and a bonus - you only need to use the one serial port on the flight controller.

As long as it sends the right NMEA message for YAW to make ArduPilot happy.

I am reminded, however, that with two F9Ps we can use one for RTK position, and one for Yaw.

With this unit, we won’t know if we have a RTK Fixed Yaw only, or a Fixed Yaw + Fixed position from the base.

You won’t know when there’s an interruption in the feed from the fixed base.

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@geofrancis any latest update, also need to have a word with you regarding skytrq ? do you have discord ?

@geofrancis did you ever get these $50 Skytraq RTK receivers working? I am looking at setting up a mower and trying to cost out the most economical solution

I haven’t replaced mine after I damaged it, it’s on my list for the summer. it has been documented to work with ardupilot so i dont see any issues using it. your probably best to use a pair and run your own base station or get the l1/l2 version at 100usd if you want to use online ntrip servers as i dont think many do l1/l5.

rtcm injection over mavlink supposedly works too so you only need a single telemetry radio.

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I’m considering biting the bullet, but might go ahead and order 10 if there are others interested in splitting shipping cost. (I need 2) Of course, would be re-shipping once they arrived, but for ground shipping, would only be $7ish. So $65/10 + $7= $14ish on top of the $50 for the module.

Looking at NS-HP-GN5 : PX1125R L1/L5 RTK BREAKOUT BOARD since I’ll be running them through a ESP32. (Choosing the L5 model since enough sats should have L5 support in the next year or two, and L5 is the future. Also cheaper, since I’ll be running my own base station)

Let me know if you are interested, and if enough folks are, I’ll do an order.

@geofrancis good to see all your posts and the details which you shared about gps sensor. I am looking for a gps sensor with 1 cm accuracy. Was wondering if you can suggest me any good option, please. I am in the US, so assuming it won’t take much longer in shipping.

can someone elabrate on how the module worked out I am considering is buying a setup too - just because of cost - good price for a hobbyist but I do not want to collect another forever (parts and project) .

can someone elabrate on how the module worked out I am considering is buying a setup too - just because of cost - good price for a hobbyist but I do not want to collect another forever (parts and project) .

Sorry, I haven’t yet ordered anything. My purpose is precision surveying, and there are enough resources online that I feel pretty confident that this module will work without an issue. I just don’t foresee having enough time in the near future to invest in the project.