The LC29HDAMD came with an antenna at a shocking price of ~ 36 €
OK, it’s the 1 Hz Version only.
And the antenna is broken … zero to one satellites in view…
And I need an extra USB UART.
An old prolific 2303 from my junk box supplies RXD, TXD and 5V - fine.
(btw:would not buy an 2303 any more, since notorius driver incompatibility issues both on WIN and Linux)
I tried loads of fiddling with another antenna
at the window sill.
Promising Level 1 fix data, but no RTK.
But Quectel supply loads of documentation, among them
/quectel_gnss_rtk_application_note_v1-0.pdf
including a chapter
5.2. Why the GNSS Module Fails to Enter RTK Solution Mode
- frequency bands of correction data have to match module
- base station should not be more afar than 30 km
- decent SNR
- open sky view
So I attached the LC29H to the antenna from previous test.
Ran BKG ntrip client (BNC) Version 2.12.18 with FPS_BY_RTCM3_4G against it - and voila - within seconds, my first RTK fix since my experiments with rtklib nearly a decade ago:
$GNGGA,203851.000,4959.058256,N,01215.597917,E,4,36,0.37,554.339,M,47.220,M,1.0,1225*50
$GNRMC,203851.000,A,4959.058256,N,01215.597917,E,0.005,249.95,180625,,,R,V*24
$GNGLL,4959.058256,N,01215.597917,E,203851.000,A,D*41
$GNVTG,249.95,T,,M,0.005,N,0.009,K,D*29
$GNGSA,A,3,05,07,08,13,14,15,18,20,22,23,30,,0.66,0.37,0.54,1*04
$GNGSA,A,3,65,75,76,77,83,,,,,,,,0.66,0.37,0.54,2*0C
$GNGSA,A,3,02,07,08,10,12,19,27,29,30,33,,,0.66,0.37,0.54,3*0C
$GNGSA,A,3,05,07,09,10,19,21,22,36,40,45,,,0.66,0.37,0.54,4*00
$GNGSA,A,3,,,,,,,,,,,,,0.66,0.37,0.54,5*00
$GPGSV,3,1,12,05,50,233,50,07,23,068,41,08,11,038,37,13,69,301,49,1*6A
$GPGSV,3,2,12,14,56,135,46,15,33,299,48,18,10,308,34,20,28,202,45,1*62
$GPGSV,3,3,12,22,45,158,48,23,05,330,37,30,56,068,49,36,29,155,45,1*6B
$GPGSV,2,1,05,08,11,038,47,14,56,135,51,18,10,308,37,23,05,330,42,8*6B
$GPGSV,2,2,05,30,56,068,52,8*51
$GLGSV,2,1,06,65,38,138,44,75,35,039,47,76,78,179,50,77,29,210,43,1*79
$GLGSV,2,2,06,82,01,290,33,83,10,336,42,1*74
$GAGSV,3,1,10,02,19,040,36,07,62,108,46,08,11,111,34,10,08,341,37,7*76
$GAGSV,3,2,10,12,14,319,35,19,12,293,23,27,36,169,43,29,58,295,46,7*79
$GAGSV,3,3,10,30,54,093,46,33,14,266,30,7*7C
$GAGSV,3,1,10,02,19,040,43,07,62,108,51,08,11,111,42,10,08,341,45,1*70
$GAGSV,3,2,10,12,14,319,40,19,12,293,29,27,36,169,50,29,58,295,52,1*70
$GAGSV,3,3,10,30,54,093,50,33,14,266,36,1*7B
$GBGSV,3,1,11,05,17,126,38,07,21,071,37,09,11,066,38,10,22,084,38,1*7B
$GBGSV,3,2,11,19,40,153,47,21,25,311,47,22,73,262,51,36,72,189,50,1*78
$GBGSV,3,3,11,40,21,064,40,45,24,220,45,60,03,109,30,1*4F
$GBGSV,2,1,06,19,40,153,48,21,25,311,50,22,73,262,51,36,72,189,51,5*70
$GBGSV,2,2,06,40,21,064,46,45,24,220,48,5*78
$GQGSV,1,1,00,1*65
$GQGSV,1,1,00,8*6C
An awful lot of 36 satellites in the solution.
Not really stable - 20 % of the time it drops to RTK float:
~/tmp/ntrips$ grep GNGGA GGA.log | grep ',E,5' | wc -l
1168
~/tmp/ntrips$ grep GNGGA GGA.log | grep ',E,4' | wc -l
4486
And a HDOP of 0.37 = 37 cm by far misses the expectation and promise of 1 cm precision.
Maybe it’s the fault of the RTK data?
I’m planning an UM980 base station and will give it a test, then, again.