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nmea and gpsd http://navigatrix.net/viewtopic.php?f=4&t=617 |
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Author: | david_302 [ 21 Mar 2014, 05:31 ] |
Post subject: | nmea and gpsd |
Hi, So im quite new to Navigatrix and openCPN (actually quite new to this whole sailing thing too...). Our boat came with quite a few gadgets and im slowly working out how they all work. I currently have a basic seatalk network with a standalone gps dome, depth, bearing, etc - so there's one nmea feed at 4800, which includes a gps signal (when that gps works!). I also have a SD GX2150, which i have wired to the seatalk (with a magical black box) so it gets a gps feed, and i have the ais feed at 38400 from the radio. I also have a usb puck gps. So thats now 3 nmea feeds (including 2 gps signals). I have all of these running through seperate serial-usb converters and a usb hub so I only have 1 usb to plug into the laptop. I was firstly just running openCPN off my mac, but found each time i reconnected the usb, the virtual serial ports all shifted around, and i had to tell openCPN which ports were which again. Then came Navigatrix. I dont understand how it does it, but all these nmea feeds magically get into openCPN all by themselves! Its awesome! Whoever set this up is a jedi. I think this is this GPSD i've been reading about, sat in the background and sorting the world out? If someone could explain it, and show me how to actually see it in action that would be great. I also have a specific question... As I said above, I have two GPS feeds. One from the little GPS dome on the back of the boat which talks through seatalk, and the other a usb puck. The gps puck obviously only works with the laptop, and so cannot constantly supply the radio with a feed. But the GPS dome thingy doesnt seem all that great. It often wont start up, and i have to power down and back up to get it to come on. Hence having the puck as a backup (which also appears to give a more accurate fix). So the question is firstly, how does the gpsd handle 2 gps feeds, and secondly, can i make one of them take priority if they are both there (but go to either, if only 1 is available)? Cheers, Dave s/v Desolina, Wellington NZ |
Author: | Moe [ 21 Mar 2014, 06:34 ] |
Post subject: | Re: nmea and gpsd |
gpsd is one of my favourite invisible applications. It handles two (or more) gps units by listen to one and ignoring the other(s). It's not fussy. The first valid gps that comes along regardless of where it's plugged in...in the current configuration. You can specify a location but would have to change the configuration if you change...the configuration. Your best bet is to have one switched off or unplugged. |
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