I have implemented support for all of the relevant Venus binary messages. It's just that I don't have a Venus timing receiver to test the timing receiver specific messages (which are only three messages that control the self-survey / position hold modes). Oh, and besides the lack of a binary message with satellite position/signal levels, there is none that reports the sawtooth error. Lady Heather's NMEA support is limited to standard NMEA messages that all receivers support (position, date/time, satellite info). The only "proprietary" NMEA commands that I send are those that can switch a receiver into binary mode. Receiver binary modes generally allow full control over the receiver. ------------------------- Maybe I'll wait til Lady Heather has a more complete communication set with this part...

Mark wrote: > Oh, and besides the lack of a binary message with satellite position/signal levels, there is none that reports the sawtooth error. How in the world can they call it a "timing receiver" if it doesn't even support sawtooth correction?? Good grief. Also, I see they claim 6nS accuracy. That is pretty much exactly 1/2 cycle of the main clock frequency, so +/- 6nS should be the expected theoretical best possible error envelope WRT the quantization error, *assuming the receiver's timing solution is always perfect.* Are we supposed to believe they achieve that accuracy in practice, despite all of the well-known sources of error in GPS timing solutions?? Best regards, Charles

The NMEA STI,00 message gives a sawtooth correction. I believe what Mark was saying was that there was no *binary* message that said so… maybe? I dunno. But the datasheet clearly talks about PPS quantization error compensation: STI,00 – 1 PPS timing report An output message, id 0x0, contains information of 1 PPS timing mode, 1 PPS survey length and 1PPS quantization error. Structure: $PSTI,00,x,xx,xx *hh<CR><LF> Example: $PSTI,00,1,1985,-12.4*1E<CR><LF> Here there’s a table that I’ll try to interpolate because pasting it failed… the 1 is the PPS timing mode. 0 = PVT, 1 = Survey mode, 2 = Static mode 1985 is the survey length -12.4 is the PPS quantization error 1E is, of course, the checksum. > On Jul 22, 2016, at 11:40 PM, Charles Steinmetz <csteinmetz@yandex.com> wrote: > > Mark wrote: > >> Oh, and besides the lack of a binary message with satellite position/signal levels, there is none that reports the sawtooth error. > > How in the world can they call it a "timing receiver" if it doesn't even support sawtooth correction?? Good grief. > > Also, I see they claim 6nS accuracy. That is pretty much exactly 1/2 cycle of the main clock frequency, so +/- 6nS should be the expected theoretical best possible error envelope WRT the quantization error, *assuming the receiver's timing solution is always perfect.* Are we supposed to believe they achieve that accuracy in practice, despite all of the well-known sources of error in GPS timing solutions?? > > Best regards, > > Charles > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.