On 14 May 2005 06:31:15 -0700, "Pascal" wrote:
Realy very haevy trafic, here it is many times small than this.
Possibly, but it mightn't always be that way, and manufacturers who build
equipment for best case scenario instead of worst case won't last long
anyway.
AIS radar operation has several limitation like:
a) It can track up to 24 ships. If there is more, it displays only the
24 more proximity
Sounds dodgy to me - what if there are 24 stationary ships around you & 1
damn fast ferry coming straight at you? Will it swap over to the important
one quick enough for you to do anything about it?
NASA AIS radar can be customized by the user which can set the update
rate to 8, 15, 30 or 60 sec.
Too slow for real-life - AIS transmitters on boats going fast & turning fast
tx at 2 second intervals (1 second if in assigned mode & assigned to 1
second), so if you have your receiver set to 60 seconds then you could be run
over before you notice it.
I believe that this limitations and controls can tune the operation in
regard to speed/power of the processor.
Sounds to me more like they make it into a useless toy. AIS is specifically
designed for collision avoidance (though it has been hijacked for homeland
security) & a lot of thought has been put into how many ships should be
processed, how often boats should transmit, etc. All these limitations make
it dangerous if someone hooks up a NASA radar & thinks that this is going to
save them from having to keep a good watch.
What do you think about? Maybe Garmin can include this setings in the
GpsMap276C AIS function. As you can see, I am crazy to use the AIS in
my boat, and I would acept any restrictions wich could be need to get
it on my Gpsmap276C.
If you really wanted to do it, you could get an AIS receiver, hook in a
computer, re-code the AIS digital signals to DSC digital signals & feed to
the 276C. However, I don't think this is something that Garmin should be
tackling as - it takes a LOT of processor power, and how is AIS going to look
on such a small display anyway? It will be far too cluttered.
Here are some screen dumps from AIS around my area - as you can see, the
screens are fairly cluttered even on a 1024x768 screen.
http://www.jodael.com/sr162_performance_testing.htm
Cheapest solution for the moment is an old notebook, free software, and an
AIS receiver like the SR162 (or NASA engine though I prefer dual-channel
receiver). If you have a notebook lying around you could be up & running with
AIS display for US$300 or so.
Dave
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