RTK FACET - ROVER configuration for BASE

Hello Sparkfun Forum!
I have two Facet V4.1. I configured one as Base and it sends me RTM3 protocols via the 898 MHz transmitter, and the second device receives these protocols as Rover. However, ROVER does not respond to these protocols and does not perform corrections. I turned off BLE because I thought it was expecting corrections from my iPhone. Unfortunately, this did not help. I checked that the protocols are entering the ZED-F9P on the ZED-RXI2 R4C signal and pin 26 and the analyzer shows that they are correct. I think there must be some incorrect setting and ZED-F9P does not expect these correctors from the serial2 port. I probably configured something incorrectly in the GUI. Unfortunately, I cannot see anything because I have too little experience with GNSS. I urgently ask for help because I would like to be independent of NTRIP through my Base and relatively measure where there is no telephone network coverage. The display shows an icon resembling a mobile phone on the left next to the Battery symbol, which confirms my belief that it is still waiting for a correction from BLE and not from BASE.
Sending warm greetings from Bavaria.
Roman (DL6NBF)

Hello Roman in Bavaria! Thanks for reaching out. What radios are you using? When I’m troubleshooting a link I often use u-center to inspect what the ZED is receiving:

UBX-MON-COMMS will show you if RTCM is reaching the ZED. I presume it’s not. But this will help you localize the problem to the radios.

Do your radios report transmit and reception? In other words, can you see blinking LEDs or other indicators that something is coming out of the receiving radio?

If some sort of data is moving over the radio link, then I suspect the radios need to be configured 57600bps, as this is the default baud for the RADIO port on the Facet (configurable, but default of 57600).

Hello Sparky,
I use a 915 MHz telemetry transmitter. I checked it with an oscilloscope and the signal seems ok. I connected to a PC and the u-center protocols also showed correct. But I did not check if the F9P receives information on the Port. Your method is better and in the next few days I will check your method! Thank you very much for your version of testing. I will give you information on what I found.
Best regards and thank you
Roman

Hello Sparky,
I noticed that on your hardcopy I don’t have visible UART2 TX2 RX2 to which I send the signal from the receiver. Did I make an incorrect connection? According to the diagram, the radio is connected to ZED-RXI2, meaning UART2 in ZED-F9P. Did I miss something, how to see Port2?.
Best regards and thank you
Roman

I’m not sure I understand your question, but the RX pin on the Facet RADIO connector should connect to the TX pin on your radio. TX pin on the Facet should go to the TX pin on your radio. The included cables can be used to accomplish this connection.

There is documentation here:
https://learn.sparkfun.com/tutorials/sparkfun-rtk-facet-hookup-guide/all

Hello Sparky,
This is how I have it connected. Pin 2 External Radio Connector (ZED-TXO2) BASE to radio input (Transmitter) and radio output (Receiver) to Pin 3 ZED-RXI2) ROVER. So the correction signal is fed to Port RX2 (Pin26 ZED-F9P). For the test Signal received from the transmitter (57600Bd) I connected to the PC using the USB Serial interface Com4 and received it via U-Center. There, after selecting COM4 via VIEW > Packet Console and Binary Console, I checked that the packets are arriving correctly.

Now, following your advice, I will connect the Receiver to ROVER and its USB to the PC with U-Center… There I will want to see if the correction packets are being received by ZED-F9P. These packets according to the diagram enter RX2 ZED-F9P Pin 26.

However, I have doubts whether this will be possible because on Hardcopy from you I do not see UART2 from ZED-F9P and your RTCM packets enter via I2C from ESP 32. It looks like your configuration receives correction packets not from Radio but from BTL or BT via ESP32.

RTCM packets when working with Radio should come directly to ZED-F9P Pin 26.

Here arises the question that I formulated in my first entry - Do I configure ROVER correctly to work with BASE and not with BLE and corrections from the Phone.

I connected to the PC using the USB Serial interface Com4 and received it via U-Center.

Can you please post a screen shot showing reception of RTCM packets by the ZED?

image

Above, by default, the ZED’s UART2, which is directly connected to the RADIO port, is configured to receive RTCM at 57600bps. Any RTCM coming in over this connector is send directly to the ZED. There is no interaction by the ESP32. Please double check that ‘Protocol in’ is set to 5-RTCM in u-center. I just tested this with a Facet and all is working well.

I do not see UART2 from ZED-F9P and your RTCM packets enter via I2C from ESP 32

To be clear, there is no I2C from the ESP32 needed for RTCM. RTCM from the RADIO port flows directly into the ZED.

Here is an updated image:

UART2 appears once the ZED detects packets on that port. In pink, the ZED has verified the reception of 122 RTCM packets. In blue, the ZED skipped 145 bytes because those packets were badly formed and failed CRC. You want the pink RTCM to increase. If it is not increasing, you have a problem with your radio link.

Hello SPARKY

I tested using your method.

Everything indicates that the F9P receives RTCM telegrams.

However, it does nothing with them. I turned on “Enable UBX Input” in the GUI, but nothing changed. I turned BLE off, but nothing changed. On the Phone, in GNSS Status, nothing improves either. Fix Type gives DGPS and the accuracy is about 50 cm. If I turn on NTRIP Client in the phone, a down arrow appears on the display in the BT logo position and the accuracy remains worse. When I turn off the radio receiver, the status changes to RTK Fix and the accuracy reaches 10 mm. What interested me is that when working with RTCM from BASE, no flashing down arrow appears, which would prove my assumption that for some reason the F9P ignores these telegrams. Maybe a telegram from BASE is missing?
I haven’t changed any default settings in the GUI.

I’m adding Hardcopies of my MSGs.

Maybe you can figure out what I’m doing wrong. That would be great!
regards
Roman
Enable UBX input ON GNSS Uart 2

Hello Sparky,
it was different for me for the input (I’m sending Hardcopy).
I corrected it for Your Version but it didn’t change anything.

Let me know if you have BLE turned off and if you have “Enable UBX Input” set. Additionally, let me know if you see any sign on the display in ROVER that you are receiving the Correction. I can’t see anything and the flashing arrow that is when connecting NTRIP via iPhone and BLE does not appear.
I’m sending pictures of the Display for BASE and for ROVER.
Maybe it will explain something.
Regards and Thank you for your Help!
Roman
PORT UART2

Hello Sparky,
I am very sorry that the dialogue has ended.

Best regards
Roman

Hi Roman - I appears your ZED is receiving RTCM packets, congrats! That’s good. But, I am sorry, I cannot explain why it is not entering RTK Float mode. Perhaps a factory reset of the ZED will clear a setting that has been set wrong. I believe you are operating on custom hardware so I will be limited with how much I can duplicate your problem.

Perhaps the base is set to the wrong coordinates. If the rover ZED is receiving RTCM, but the RTCM is very low quality, the ZED will reject the corrections and not enter RTK Float. Is the base in Survey-In or fixed mode?

Hello Sparky,
Thank you very much for your answer!
It is quite possible that you are right. I set up the Base antenna in the garden and measured the position using the NTRIP Server and when SW MAP showed an accuracy of 10 mm I noted this position and programmed it in the Web configuration as a static position. Maybe it was not accurate enough or the antenna moved a little. However, that is not what I wanted.

I would like to have an accurate measurement relative to the Base to measure in any place, even where I do not have access to the mobile network. Since I only want a relative measurement, I probably programmed the base incorrectly by providing the supposed coordinates of its position in the WEB setting.

I would very much like to ask you for detailed information on how to set up the BASE so that it meets my expectations. From your last information it appears that if the Base position is not accurate then it cannot be set the way I did it!

Best regards
Roman

Maybe it was not accurate enough or the antenna moved a little.

No, I don’t think that is the problem. In my experience, a base must be significantly distant from it’s assigned fixed position to cause issue - ie, 100s of meters or more before the base will fail to start, or a rover will have problems with the incorrect base corrections.

I set up the Base antenna in the garden and measured the position using the NTRIP Server and when SW MAP showed an accuracy of 10 mm I noted this position and programmed it in the Web configuration as a static position.

That should work fine. The best is to do a 24-hour PPP, but what you did is good enough for testing.

I’m really not sure what could be causing the Rover not to enter RTK Float.

Hello Sparky,
I’ll want to do the test a little differently.

First I’ll set one device as BASE.
In this case it will be a Base with an arbitrary position that I don’t know exactly. Because I won’t need an absolute measurement.
898 MHz radio connected to J9 or J11 (RX + TX) 57600/8/N1

Here I need your help on how to configure Base via GUI (Firmware 4.1)

ROVER will connect to iPhone via BLE.

SW MAPS will start and I’ll see GNSS Status.
I don’t run NTRIP on the phone.

I’ll also need GUI settings for ROVER from you. **

I’m waiting to see GNSS Status on iPhone. In the case of an accurate measurement (relative to the BASE) Fix Type : RTK Fix should occur. (WITHOUT STARTING NTRIP CLIENT in the iPhone.)

Is this test procedure correct?

** (It is possible that the settings for Rover in the GUI will be the same as when working with NTRIP and iPhone, confirm this to me because the device with my setting with NTRIP in the iPhone worked perfectly. I get RTK Fix (10mm)
after a few minutes from switching on)