RTCM MSM7: Send 1077, 1087?

[jake.harders]

Hi all,

I am interfacing with a device that requires the 1077 and 1087 RTCM 3 commands. There are options to send these “Type 7” messages different formats (1097:Galileo, 1107:SBAS/WAAS, 1117:QZSS, 1127:BeiDou).

I believe the ublox chip onboard the Reach RS is capable of generating these messages. Is there a way to configure the Reach RS do this?

Any input is appreciated.

[dmitriy.ershov]

Hi Jake,

I am afraid it can’t be done in the current version of ReachView.

[jake.harders]

Hi Dmitriy,

Thanks for your reply!
I guess what I am really asking is:
“Is there a way to configure the messages outside of ReachView?
Is this a software or a hardware limitation?”

Thanks for your help!

[dmitriy.ershov]

Jake, you can try to ssh into the unit and edit messages output here:

/etc/reachview/stable_settings.json

However, I’m not hundred percent sure this will work.

[jake.harders]

Dmitriy,
I found “/etc/reachview/stable_config.json” and edited the file by adding this:

I restarted the Reach RS and nothing is different.

Thanks trying I really do appreciate it.

[tatiana.andreeva]

Hi @jake.harders,

I’ve tried to enable transmitting 1077 and 1087 messages on Reach base.
Please make sure you’ve accomplished the same sequence of actions:

1. Ssh to Reach
2. Edit /etc/reachview/stable_config.json:

3. Reboot the Reach
4. Enable Base mode in ReachView
5. Configure correction input on another Reach unit to make sure these messages are transmitted:

[jake.harders]

Thanks for your help Tatiana!
However I did try this method already and while this does work for the TCP connection I require the 1077 and 1087 to be output to the serial port. I have a pair of radio modules. One plugs in to the reach. the other is in another device along with a ublox neo m8p.
Your input is greatly appreciated. Thanks again!

[tatiana.andreeva]

Hi @jake.harders,

I’ve repeated with external UART radios, everything works just fine:

Could you please list step-by-step actions you’ve performed with screenshots? I want to make sure you’ve configured everything correctly.

[jake.harders]

Hi!

Okay I will take you through what I am doing.

Step one: SSH into Reach

Step two: Edit /etc/reachview/stable_config.json

Step three: Reboot Reach

Step four: Enable basemode

Step five: Configure input on another Reach unit to make sure the messages are being transmitted

Radio communication confirmed

No correction.

Edit: I am in in a screen room with a GPS repeater. It is not the best setup but it is very repeatable. Also I made sure I was transmitting by probing the serial connection and viewing the rtcm messages as they were being sent from the Reach.

Edit 2: The most interesting thing is that I am getting correction data and it is being saved on the Reach. I can share those logs with you if you think that would help

[tatiana.andreeva]

Hi @jake.harders,

As I can see from the last screenshot, there are no corrections at all. The message “Connected to /dev/ttyMFD2” is showed always when Serial input is enabled.

It means there is no link between the base and rover.

Could you please double-check you’ve connected radios in the proper way? Now it looks like a connection issue.

I’d also recommend you to connect one Reach unit to another over RS-232 to make sure the issue isn’t from receivers side.

[jake.harders]

Hi Tatiana,

I connected the two together via RS-232. Kinda funny looking.

And using this pinout
gnd->gnd
tx->rx
rx->tx

Same story, no correction.

*edit: my next steps

1. probe rx pin on the “rover” to ensure the data is being transmitted
2. reverse roles. reconfigure base to rover and vise-versa.
3. use ublox development board to outputt corrections messages (1005,1077,1087) via RS 232

Please let me know if you have any other suggestions

[tatiana.andreeva]

Hi @jake.harders,

@jake.harders

use ublox development board to outputt corrections messages (1005,1077,1087) via RS 232

Could you please try to receive corrections over RS-232 port on both Reach RS+ units?

Please keep me updated with your tests.

[jake.harders]

Hi Tatiana,

I spent a few hours trying to get this up and running with the ublox C94-M8P. I followed the instructions in the application guide for a wired connection between two C94-M8Ps

C94-M8P J8 Connector--------> Emlid Accessory cable
Pin 3: Ground---------------> RED,BLACK,GREEN: Ground
Pin 10: TXD-----------------> Orange: RXD
Pin 20: Radio Enable--------> External power supply: 3.3V

I tried this with both of the Reach RS units I have to no avail.

I went ahead and recorded the waveforms and measured the baud rate.

Waveform looks ok. Two things of note,

1. It is held high and then pulled low to communicate.
   2)The logic is at 3 volts unloaded

I decided to see how this compared to the Reach RS output (TX):

Surprise! it is different!
It is idle at -7.5 volts and pulled to +7.5 to communicate

So I ran into the difference between TTL and RS-232. So embarrassing.
All this time it was a protocol difference I did not even think about. I threw together an RS-232 to TTL converter and everything works just fine. Corrections are being received by my device. I am glad I found this although still a bit frustrated with myself it took so long.

Thanks for all your help along the way!

[tatiana.andreeva]

Hi @jake.harders,

It’s great news!

The thing was tricky, glad to hear everything works now.