Hi Marco (@bamarcant ),
Did you really mean 5700 baud? Or was it 57600 baud?
If it was 5700, what were your message rates / intervals?
Thanks!
Paul
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Pardon, I missed ( was late for me too).
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I donât use the breakout boards so I donât have any educated opinions to share.
I will throw out a general idea for consideration, just in case it sparks something useful:
We consider the LG290P to be a quad-band receiver, using the L1, L2, L5, and L6/E6 frequency bands. We consider the F9P to be a dual-band receiver, using L1 and L2 (with some variants swapping out L2 for L5, but never both).
The PostCard (LG290P w/ ESP) is performing the Base operations, sending RTCM3 to whoever is listening over the radio link. It appears that a huge amount of observation data is being crammed over the radio link. I assume the F9P gets the luxury of simply ignoring the L5 observations in the RTCM3 ? My guess is that maybe the LG290P Rover is bombarded with data and doesnât get the chance at even a RTK Float before it has to start handling the next epoch from the base. (I realize thatâs a Big guess).
Similar to @PaulZC comments, my suggestion would be to start with a working system first. Turn everything OFF in the Basestation Postcard except the GPS constellation. Start with MSM4 only, for GPS only, at 1Hz. Do not send any NMEA data from the Base PostCard, it serves no purpose. Once you confirm the LG290P breakout Rover can achieve a RTK Fixed Solution, you add more data to the radio link. I would add constellations and confirm before finally testing MSM7.
If your 2ând hand LG290P breakout board has malfunctioned, you wont get past step 1 in the proposed test.
Since my only active L1/L2/L5 antenna is being used with the RTK Postcard, I have ordered an additional active L1/L2/L5 from Spakfun which should arrive by next Thursday.
TCIII
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Hi @TCIII ,
Thanks for the update.
If you have time before then, please do try disabling the NMEA messages. I am hopeful that reducing the number of messages passing through your radios will allow you to achieve RTK Fix.
Please be aware that MSM7 will almost double your radio traffic, compared to MSM4. The official figures are: 5929 bits for Nsat=16, Nsig=4, compared to 3593 bits for MSM4.
I hope this helps,
Paul
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Thanks for the response, much appreciated.
Correct me if I am wrong, but I believe that only RTCM3 messages (1005, 107X, 108X, 109X, 1112, and 1124 are being transmitted over the RTK Postcard UART3 Radio link?
Additionally, I tried using the LG290P RTK GNSS Breakout Board with my ZED-F9P RTK GNSS Base Station and got the same results as with the RTK Postcard.
TCIII
Hi @TCIII ,
If youâre still using the defaults, then the standard NMEA messages will still be enabled. They arenât automatically disabled when you enter Base mode. Please check the message menus. If you see this, theyâre enabled:
When disabled, you will see:
I hope this helps,
Paul
@TCIII : there is another setting which will help:
On the LG290P, from firmware version v04, it is possible to set different message rates on different ports. (That wasnât true with the original v03 firmware.)
We added a setting which allows you to selectively disable NMEA on UART3 - the âRadioâ port. You will find it in the Ports Menu. With v2.2 firmware, it appears as â5) NMEA output on radio UART3â:
In the more recent Release Candidate firmware, it appears as â5) Limit RADIO port output to RTCMâ:
On 2.2, it defaults to: â5) NMEA output on radio UART3: Enabledâ. On the RC, it defaults to: â5) Limit RADIO port output to RTCM: Disabledâ. The setting is actually the same, it is just the wording that is inverted.
I hope this helps,
Paul
Remaining with the matter that RTCM MSM7 may be too heavy for a radio_wifi transport I analyzed and verified the following:
at 57600 8N1 the transmission manages to send the differentials for the correction without problems by virtue of the fact that at 57600 baud, considering that being able to admit that there may be oversample cycles to the bit for a nMHZ clock rate by 4, 8, 16, 32; but even without oversample cycles, theoretically the stream can be 7200BpsâŚ57.6kbps.
In fact, transmitting a file received at 57600baud in 10s took 4.35s to completely transfer indicating approximately 3900Bps.
In the figure the router has determined a maximum value of 38.2kbps which corresponds to the sending of the ephemeris every 30s; in the interval cycle (from 1 to 29)s it consumes approximately 11.4kbps.
This morning the sky was cloudy but the LG290P base_module tracked 29 valid satellites out of 40 when clear sky.Later tried and the rover_receiver changed to fix without problems.
Of course the settings for base are like those indicated above i.e.
Set the base in ecef
$PQTMCFGRTCM,W,7,0,15,07,06,2,30*36
Enable all ephemerides
Disable antenna descriptor $PQTMCFGMSGRATE,W,1,3,RTCM3-1033,0*5F
No Nmea as default in $PQTMCFGRCVRMODE,W,2*29
naturalmente $PQTMCFGUART,W,3,57600*34 !
On the breackout board disable all NMEA sentences if not useâŚU can read status on another port.
$PQTMCFGMSGRATE,W,1,3,GSV,0*0A
$PQTMCFGMSGRATE,W,1,3,GSA,0*1D
$PQTMCFGMSGRATE,W,1,3,VTG,0*0D
$PQTMCFGMSGRATE,W,1,3,GLL,0*0F
$PQTMCFGMSGRATE,W,1,3,GBS,0*1E
$PQTMCFGMSGRATE,W,1,3,GNS,0*12
$PQTMCFGMSGRATE,W,1,3,ZDA,0*17
$PQTMCFGMSGRATE,W,1,3,GST,0*08
so not only Postard but rover side need to disableâŚ
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Thanks for the response, much appreciated.
I disabled NMEA output on radio UART3 and still no RTK Fix.
On the other hand, the ZED-F9P on the Rover is still able to achieve RTK Fix at 57600 baud with the NMEA messages disabled on the RTK Postcard Radio port.
As for the LG290P on the Rover, is there a QGNSS command to make sure that the Radio port is enabled to allow incoming corrections or would I even be getting RTK Float if it was not enabled?
TCIII
Please on the rover, run the above commandsâŚ
@TCIII , what antenna are you using at the Rover(s) ?
To be 100% unbiased, we should also recognize the tiny âpossibilityâ that the LG290P is correct to remain in Float condition, due to environmental or even systematic reasons. IE: Multi-Path, incompatible Pre-Filter inside the antenna, passive antenna, etc.
Admittedly the dual-band F9P achieving a Fixed solution is a good indicator, but Iâve never personally tested a LG290P Rover without a L1/L2/L5 antenna.
Thanks for trying that @TCIII ,
Shame itâs not the magic wand I was hoping for.
It is possible to disable the RTCM protocol on UART3. But, indeed, you wouldnât get RTK Float if it were disabled. $PQTMCFGPROT,R,1,3* would confirm. 00000005,00000005 indicates all is well on v05. On v06, you should see 00000007,00000007.
Other than removing the radio and connecting the two with good old copper wire, Iâm completely out of ideas. Marco, Ryan and Clive have given you a bunch of good advice. Hopefully enough to let you solve this.
Happy Halloween!
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Thanks for the responses, much appreciated.
I was able to borrow a L1/L2/L5 active antenna and that along with disabling the NMEA messages in the UART3 Radio output got the Rover LG290P to display a solid white RTK LED indicating a RTK Fix solution.
Thanks for all of your assistance and help Gentlemen!
Happy Halloween to you too Paul!
TCIII
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