Tom, Please see:
https://www.novatel.com/assets/Documents/Manuals/om-20000128.pdf https://www.novatel.com/assets/Documents/Manuals/om-20000129.pdf OEM628 and OEM638 boards can take an external frequency reference (218/4.10.5), but OEM615 cannot. I've never tried it. To get the exact time of the PPS you need to enable the TIME message (219/3.2.173) with something like (untested): LOG TIMEA ONTIME 1 A typical way to use the Novatel solution is to wire signals for the events of interest -- say a camera shutter or start of frame (SOF) or a LIDAR start of scan (SOS) -- into the receiver on one of the several event inputs. With a suitable configuration, the log will contain messages with the current 6-dof + time solution for the event edges. If you are also logging the full receiver state, you can post-process the events into better 6-dof + time solutions. -- Christopher 73 de AI6KG On Mon, Oct 9, 2017 at 1:02 PM, Tom Van Baak <[email protected]> wrote: > Christopher, > > Thanks for that additional information. Can you (or Gregory) also comment > on the external frequency input / output and the 1PPS output of this > receiver? > > A quick look at the om-20000128.pdf and om-20000129.pdf documents has > words like "better than 250 ns accuracy" and "50 ns increments" but I > didn't see mention of 1PPS quantization, sawtooth correction, or other > words commonly used in GPS timing receiver specifications. I'm guessing > this product is mostly designed for the PN part of PNT (Positioning, > Navigation, Timing)? > > /tvb > > ----- Original Message ----- > From: "Christopher Hoover" <[email protected]> > To: "Discussion of precise time and frequency measurement" < > [email protected]> > Sent: Monday, October 09, 2017 12:35 PM > Subject: Re: [time-nuts] Novatel Dual frequency GNSS receivers on ebay > > > >I have quite a bit of experience with Novatel hardware include OEM6, CPT > > and SPAN. > > > > CPT is an IMU made by KVH and relabeled by Novatel. The accelerometers > > are MEMs and the roll rate sensors are FOGs. Pretty old design. > > Performance is decent (but not auto alignment good). > > > > http://www.kvh.com/Military-and-Government/Gyros-and- > Inertial-Systems-and-Compasses/Gyros-and-IMUs-and-INS/IMUs/CG-5100.aspx > > > > SPAN is the "solution." SPAN-CPT puts the CPT IMU and the receiver in > a > > single box. You could also get just the CPT in a box. > > > > The feature set enabled depends on the software keys that are loaded. > > Caveat emptor. > > > > Dual receiver (even if you have the hardware) and ALIGN feature are extra > > features. > > > > Also worth noting is that the circular connectors used on some of the > > hardware are pricey. Some are impossible to assemble without specialty > > tools. > > > > -- Christopher. > > 73 de AI6KG > > > > > > On Sat, Oct 7, 2017 at 2:36 PM, J. L. Trantham <[email protected]> wrote: > > > >> Any idea what they are selling for at this time? > >> > >> I see that some sold for the BIN price of $349.99 up until June 20. > After > >> that, 'Offer Accepted' occurred up through October 5, with a BIN price > now > >> of $649.99, all plus $40 shipping. > >> > >> Joe > >> > >> -----Original Message----- > >> From: time-nuts [mailto:[email protected]] On Behalf Of > Gregory > >> Maxwell > >> Sent: Saturday, October 07, 2017 2:17 PM > >> To: Discussion of precise time and frequency measurement > >> Subject: [time-nuts] Novatel Dual frequency GNSS receivers on ebay > >> > >> There is an ebay listing for "Novatel GPS-702-GG with SPAN-CPT Single > >> Enclosure GNSS/INS Receiver + Cable" with a fairly large number > available. > >> > >> This is a Novatel OEM628 dual frequency receiver (supports GPS, Glonass, > >> SBAS, apparently including L1C and L2C), plus a three fiber ring gyros > >> (with bias performance that blows away any mems gyro I've ever used) > and an > >> 3-axis mems acceletrometer in an aluminum case, plus a decent dual > >> frequency antenna. This is a generation-ish old kit. > >> The industrial casing conspires to make it look somewhat less modern > than > >> it actually is. > >> > >> The receivers have external clock input (though not plumbed to the > outside > >> of the case) which appears to work though I didn't try much with it yet. > >> Mine came with 2013-ish firmware but easily upgraded to current (2016) > >> firmware. There is a windows based firmware update tool which talks to > it > >> over serial and is very straight forward (The firmware update > OEM6631.zip > >> can be found via google). > >> > >> You can communicate with them over serial in ascii, there is extensive > >> firmware documentation that goes over every command > >> https://www.novatel.com/assets/Documents/Manuals/om-20000129.pdf some > of > >> which are specific to other modules. There is also a separate manual for > >> the inertial navigation specific features (NovAtel SPAN-CPT Users > >> manual.pdf) > >> > >> The external clock should allow you to hang it off a more stable > >> oscillator which will improve the stability of the GNSS results, and _I > >> presume_ improve the quality of the PPS output-- the firmware manual and > >> operating manual are thin on details, and mostly just go into telling > you > >> how to adjust the kalman filter constants for different clock types. > >> > >> These also appear to support the novatel 'align' mode where you serial > >> connect two receivers separated by a short baseline and get really > accurate > >> absolute headings; I'm planning on trying that that but haven't set it > up > >> yet. > >> > >> Looks like uber (last position was ubers offices in denver) had a fleet > of > >> these things. The couple I got run great, including the IMU, the > antennas > >> obviously spent a long time outside, but work fine. The cable they come > >> with is weird, but I had no problem chopping one end off and figuring > out > >> the pinout (see bottom). > >> > >> The novatel OEM6 is well supported by rtklib and I was able to get > >> post-processed positions very easily. > >> > >> Seller takes best offers a fair amount below the $649 asking price. > >> Looks like they may have another 30 or so of them. > >> > >> May be useful for doing time transfer especially with the clock input. > >> Just using it to get nice dual band observations to precisely survey an > >> antenna location for a traditional GPSDO may improve GPSDO performance > by a > >> fair amount. > >> > >> Here is the signals and wire colors on the cables mine came with. > >> YMMV, I'd suggest not blindly trusting that colors match on other > >> units. These cables don't plumb out many of the signals from the > >> module (in particular, they don't carrying COM2, which is why I haven't > >> tried multi-receiver headings yet, since I'd need to figure out how to > talk > >> to it over USB if com1 is in use for that), I'm unsure if they're wired > >> through the to external connector. > >> > >> 01 white power return (-) > >> 02 brown 9-18 VDC power input (+) > >> 03 yellow COM1 RS232 TX > >> 05 pink COM1 RS232 RX > >> 09 green COM1 GND > >> 10 black USB D+ > >> 11 purple USB D- > >> 12 yellow brnstp USB GND > >> 15 red ODO SIGA > >> 16 blue ODO SIGA-inv > >> 29 grey pinkstp PPS (high resistance? 80 ohm) > >> 30 whitw grnstp Event1 > >> 31 red blustp signal ground > >> _______________________________________________ > >> time-nuts mailing list -- [email protected] To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > >> _______________________________________________ > >> time-nuts mailing list -- [email protected] > >> To unsubscribe, go to https://www.febo.com/cgi-bin/ > >> mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > > and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
