The only problem is, in the linked User-Guide you dont find the SDA and SCL pins… They should next to TXD on pins 6/7 as you find on the datasheet of the PX1122R I think…
On the hookup drawing they take the NMEA output from Receiver B… I think and hope there is also an NMEA output on Receiver C as AOG expects an $PSTI,032,… message in the NMEA stream with up-projection and baseline-length between the two antennas on tractor wich could only be taken from Receiver C and NOT from Receiver B (we dont need the baseline-length and up-projection between our static base at home and the rover on tractor)
I got an evaluation board (has the SCL & SCA pins marked) and a breakout board (pins not well marked). I have them working with NTRIP and together on a short baseline. I’ll have a go at flashing the new firmware and see what messages come from what. That diagram implies to me that receiver C gives information back to receiver B? Maybe the PSTI message from receiver B is modified. I have been turning off the SkyTraq messages (because I didn’t understand what they were for). Mine are still on the bench being tested and not on the tractor yet…
For a PCB I would be inclined to design it for the breakout board as a socketed component rather than as a smd chip as it would be a bit more serviceable in that you could remove the modules and and easier to solder given the chip is the most expensive component.
Yes I would totally agree with you, but I can report, that this small coax connector on the breakout-board is really fragile… I’ve had some issues with antenna connection on my base und gnss-stick setup with the breakout-boards. This is why I would prefer the evaluation board or the small smt receiver wich is also the cheapest. (99$ SMT; 125$ breakout; 150$ eval.)
Yeah those antenna connectors are tiny. The sma connector is a lot better.
5Hz is a bit on the slow side from recommended isn’t it? I wonder if that’s a comms between receivers constraint or processing constraint?
I’ve discovered that our state’s CORS network has recently become a free service whereas it used to be subscription (eye wateringly expensive) only so I no longer need my own base. That leaves me with a spare receiver so dual gps would be a good use of it.
I just set up in the pickup to test. Connected everything according to the navspark outline. I took my rfd900 antenna out of the tractor for rtk. I am not getting the rtk correction through the module. Works good on the ublox c099 board.
If you look at the pictures, without rtk, the vehicle always points north, however with several trips around my driveway on baseline, the vehicle is pretty close to center, and the antennas are left side and right. Have tried reversing them and front to back both ways.
I did update the firmware off of the website, and made the rover a moving base, and the master a kinetically moving base and normal. Also tried float.
I wonder, since it gets heading from the rtk base, it that is my problem, but I don’t read anything to help correct the lack of rtk connection. If anyone knows please respond.
Did you chose dual GPS as source for heading in AOG? I think its on sources tab in settings, but don’t have AOG here at the moment…
For the rtk position I think as far as I understand the answer in NavSpark forum we could get this from moving base receiver, but not from the rover behind moving base…
The heading as implemented by SkyTraq/NavSpark now is different from what I coded in AOG. The parsing of the NMEA stream in AOG looks for the baseline course in PSTI,032,… message. This is should be the direction to static base if using receiver B and the direction to moving base if using receiver C. After parsing the code turns the direction by 90 degree to get the actual vehicle heading. Similar with the roll: Parsing takes up-projection from PSTI, 032,… message which should again be different if using receiver B or C output… The heading as defined by SkyTraq is in some different NMEA message which isn’t read by AOG at the moment but should be the same on receivers B and C.
I hope you understand what tried to say… English is not my mother tongue
It would be really nice, @Jhmach if you would post some lines of the NMEA output of moving base B and rover C receivers if you don’t mind to give your coordinates to us.
I do have dual antenna selected in aog. As I understand it, the skytac should receive rtk through rx2, and show rtk radio in gnss viewer. However gnss viewer show 0 in rtk radio. I feel certain about my signal from base to rover radio, but it seems the skytraq in not set to receive it. I wonder if you or someone else has a single skytraq rover successfully receiving rtk through a radio, as I am still new to rtk.
OK, something in your setup doesnt work, hard to find out what is wrong with it from here…
Yes, I have a working setup with base and single rover. Base (also the PX1122R) on the roof of my house broadcasting rtcm3 to the internet and rover connected via a bluetooth-serial adapter to my android phone with lefebure ntrip client or over usb to AOG (with integrated ntrip client). Working pretty good and giving rtk position after some seconds.
As far as I could see from your pictures there is no connection to base station or moving base (or at least no calculation of correction) and therefore no heading or anything. Also there is a lot of change in satellite signal as they are changing from one picture to the next although there are only a few seconds in between… This might also be a reason there is no RTK. Maybe you have to check your antenna connection/placement.
By the way: Could you state which receiver you are talking about when giving pictures or messages? I think for the recent posts you always took output from Moving Base (Receiver B) as described in the picture from NavSpark.
I just backed out of the barn a few feet for those pictures. Signal is good out away from the barn. I have reciever b USB going to computer for nmea. Rfd900 radio TX is connected to rx2 on reciever b.
I am going to go snap a picture of my software version, I just downloaded it 2 nights ago, and just assume it is the correct one
What I meant is the Version of the GNSS Viewer (the windows software). You could read the version number next to the name of the program on the top. Or at Help → About:
Ya I was meaning the firmware to get dual antenna working. I went ahead and updated the gnss viewer anyway. I was so concerned with getting parameters set that I had forgot to move the jumper on the boards to communicate with the pins. I now have rtk fix with baseline length and course, but the vehicle in aog is still pointing to the north. PSTI, 032 message is in the nmea string, and nmea messages are turned on, but there is still no heading or roll. Was trying to send another picture but cant get it to download
Hmm… There should be an output if the settings in AOG are correct… But even if there would have been the data in AOG, we couldn’t use them as this must be baseline data between moving base and static base at home: you are about 35 m away from it and about 3m lower.
It is more interesting what nmea output the rover (C) gives. There should be the necessary baseline data between B and C, but is there also rtk position?
I have been curious about that as well. I find no place for distance between antenna or position.
I did remember your post about the parsing in aog, so I loaded v4310 and went back to try. Now it wont go into rtk. Going out to check base and radios first
Is the code in aog different in respect to my problem than v4.1?
I put radio back in the tractor and backed out of the barn. Immediate rtk fix. Put it back on the skytraq and the base is the same but no rtk. the rover showed rtk at 1hz interval which is what I set the base output for testing. Then the base stopped showing any GPS and say no position fix available. So I reset to factory and started over. Got satellites back but still no rtk. When I tried to use one of these modules for a fixed base it did the same thing. Go back and check after a while and the strength bars would all be white . Wide open skies. I am wondering if there is a problem with these modules, or maybe in the firmware. The one I’m using as a rover in the high crop will do the same thing right in the field it just loses all sattelites. Am I missing something ?
My modules are marked. I ordered a couple ublox antennas today. Will give it a try soon as they come in.