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Portable Gps/Plotter with AIS-Receiver Support
Anybody knows one? I am using a non portable solution: SR161 + Laptop
+ GpsMap 276C. I would like to have a gps/plotter portable (or handheld), WeatherProof and useable in the cockpit. I have asked Garmin to give the AIS receiver supprt on the GpsMap 276C but after waiting 2 years I have quit. Thanks Pascal |
Portable Gps/Plotter with AIS-Receiver Support
Why don't you buy two serial to blue tooth adapters (cable replacement) from
Aircable, set them to 38400 baud for transmission of AIS data to your chart plotter. Keep your AIS receiver with VHF antenna connection inside and chart plotter in cockpit. The small bt-module is easy to water-proof for use in the cockpit. plano "Pascal" wrote in message ups.com... Anybody knows one? I am using a non portable solution: SR161 + Laptop + GpsMap 276C. I would like to have a gps/plotter portable (or handheld), WeatherProof and useable in the cockpit. I have asked Garmin to give the AIS receiver supprt on the GpsMap 276C but after waiting 2 years I have quit. Thanks Pascal |
Portable Gps/Plotter with AIS-Receiver Support
Thank You for the good idea, I have made a look in the AirCable site
and seems a good way to eliminate cables, but prior to use this, I must have an AIS enabled Gps/plotter, which is what I am looking for at the moment. Regards Pascal |
Portable Gps/Plotter with AIS-Receiver Support
"Pascal" wrote in message oups.com... Thank You for the good idea, I have made a look in the AirCable site and seems a good way to eliminate cables, but prior to use this, I must have an AIS enabled Gps/plotter, which is what I am looking for at the moment. Regards Pascal 2that come to mind Raymarine C-series, Standard Horizon CP175-C ......... plano |
Portable Gps/Plotter with AIS-Receiver Support
plano wrote:
"Pascal" wrote in message oups.com... Thank You for the good idea, I have made a look in the AirCable site and seems a good way to eliminate cables, but prior to use this, I must have an AIS enabled Gps/plotter, which is what I am looking for at the moment. Regards Pascal 2that come to mind Raymarine C-series, Standard Horizon CP175-C ......... plano I'm sure Pascal's glad you didn't mention Garmin ;-) |
Portable Gps/Plotter with AIS-Receiver Support
Ok, but as I have said, I want a "Portable" unit.. I know that there
are many models of gps/ploters that are AIS enabled, like those more recent units from Garmin, Navman, Raymarine, etc but none of them are "portable" (that is, battery operated and easily removable to be used in another boat and at home). Of course, the ideal for me would be a portable or handheld unit wicth would be a combined "Gps-Plotter-AISReceiver" all in one, but in lack of integrated AIS, the unit could be at last AIS Ready, using a external AIS Receiver, preferentially, with integrated Bluetooth. The classical "Nasa AIS Radar" was a very good idea, since in reality, we really do not need a chartplotter, but it is not portable and not weather proof to be used in the cockpit. Thanks Pascal |
Portable Gps/Plotter with AIS-Receiver Support
"Pascal" wrote in news:1172160465.780416.309310
@q2g2000cwa.googlegroups.com: I know that there are many models of gps/ploters that are AIS enabled, That all sounds good until you look at what comes out of the AIS at 38,800 baud RS-232 level data....then look at the GPS/Plotters plodding along on RS-422 (NMEA-0183 isn't RS-232C compatible) at 4800 baud..... Wrong baud rate, wrong voltage levels, INCOMPATIBLE AS USUAL.... "AIS Enabled" just means they'll read an AIS statement IF IT COMES IN AT NMEA'S slow baud rate with the rest of the NMEA data. You can't just plug them in, of course. On Lionheart, our current configuration is an SR-161 receiver feeding a Radio Shack RS-232C serial to USB interface cable ($10) plugged into a USB port on the Dell Latitude notebook running the accompanying virtual serial port software so The Cap'n nav software can find the 38,800 baud data stream on what it thinks is a serial port. NMEA system data comes in on another virtual serial port from my wireless router on the NMEA system. The Cap'n regurgitates the AIS data statements at 4800 baud to the NMEA system so it will show up on any instruments capable of reading it. SOME, not all, models of Raymarine and Garmin are capable of reading it from the NMEA stream IF you upgrade their firmware or buy something new. Currently, seeing the ships on the computer display chart is fine...(c; I want to add another Webfoot RS-232C to Ethernet adapter to our Wireless system. When I get that installed, I'm going to feed it the AIS data from the SR-161 receiver. Being on a separate hard-wired Ethernet address on our LAN, I'll be able to connect to its LAN IP address with the second virtual serial port driver that comes with the Webfoot and can eliminate the current Radio Shack hard-wired USB connection AIS is attached to......making both NMEA at 4800 baud and AIS at 38,800 baud available to The Cap'n WIRELESSLY so it will run anywhere on the boat...or even at the yacht club bar if we dock the boat at the club... (c; NMEA out/in 1 4800 baud--Webfoot 1--Netgear wireless router port 1| | AIS SR-161-38.6Kbaud-----Webfoot 2--Netgear wireless router port 2| | RF-wifi radio link--------------| RF-Wifi radio in laptop-|-Virtual serial COM2--The Cap'n NMEA in | |-Virtual serial COM3--The Cap'n AIS in Larry -- http://www.youtube.com/watch?v=fEJmc...elated&search= |
Portable Gps/Plotter with AIS-Receiver Support
Does it make sense ??
It's hard enough already to read the disply on portable units. Adding AIS data on top will just make it totally unreadable. You might be able to read at home, in good light and with you glasses on, but in the boat, dark, raining and in a "windy and critical" situation, you wouldn't be able to see anything .... Bjarke "Pascal" wrote in message ups.com... Anybody knows one? I am using a non portable solution: SR161 + Laptop + GpsMap 276C. I would like to have a gps/plotter portable (or handheld), WeatherProof and useable in the cockpit. I have asked Garmin to give the AIS receiver supprt on the GpsMap 276C but after waiting 2 years I have quit. Thanks Pascal |
Portable Gps/Plotter with AIS-Receiver Support
Well Bjarke, I have seen the AIS data on a Garmin GpsMap 3205 and I reputed the 5" size very good. Course that the display of targets on a RayMarine C80 I had seen too, is better. All wil depend on the zoom level you set the unit, and I think that in regions with no very heavy traffic like here, if it will show about 10 targets at the 5 nm range, this will be very visible. Anyway, in a critical situation, I could reduce the chart detail on the plotter (declutter) and the best thing will be to hear the alarm and see the ship name, course, speed etc. I have used Ais in my Notebook with SeaClear and ShipPlotter and it is fine, the problem is the size of the laptop, the current drain, the mess of cables etc. And what I want is to have all this information at the helm, not below at the nav table. Regards Pascal On 22 fev, 16:47, "Bjarke M. Christensen" bjarkeNG@grevestrand_punktum_danmark wrote: Does it make sense ?? It's hard enough already to read the disply on portable units. Adding AIS data on top will just make it totally unreadable. You might be able to read at home, in good light and with you glasses on, but in the boat, dark, raining and in a "windy and critical" situation, you wouldn't be able to see anything .... Bjarke |
Portable Gps/Plotter with AIS-Receiver Support
"Bjarke M. Christensen" bjarkeNG@grevestrand_punktum_danmark wrote in
: Does it make sense ?? None of the receivers make any sense, actually. They don't tell "THEM", up there on the bridge 200' above the sea and 150' above your mast, that you are THERE and going THIS WAY. No alarms go off as they STILL CAN'T SEE YOU! So, none of these receivers make any sense. What DOES make sense is for a boat TRANSPONDER to make YOU a target on THEIR plotter to be reckoned with. You would set off the alarm long before you were pushed under the bow waves and into the screws. He wouldn't have to try to "see" you down below the level of the containers piled high on the deck in front of him for 950 feet. He could "see" you, who you are, WHAT YOUR BOAT NAME AND CALLSIGN IS, where you're headed, your course and speed, right on his automatic plotting board. Armed with this information, he'd CALL YOU on VHF to warn you to get the hell out of his way. Until we bleed all the big yachts for thousands and thousands of dollars http://store.milltechmarine.com/acrglaistr.html and allow the Chinese electronics companies to send TRANSPONDERS to the yachtie countries, like the USA and Danmark, that don't cost any more than any other overpriced VHF radio at some marine electronics shop.....you won't be a target on his plotter and be on your own. Pity..... Larry -- http://stinet.dtic.mil/cgi-bin/GetTR...61&Location=U2 &doc=GetTRDoc.pdf |
Portable Gps/Plotter with AIS-Receiver Support
"Larry" wrote in message ... "Pascal" wrote in news:1172160465.780416.309310 @q2g2000cwa.googlegroups.com: I know that there are many models of gps/ploters that are AIS enabled, That all sounds good until you look at what comes out of the AIS at 38,800 baud RS-232 level data....then look at the GPS/Plotters plodding along on RS-422 (NMEA-0183 isn't RS-232C compatible) at 4800 baud..... Wrong baud rate, wrong voltage levels, INCOMPATIBLE AS USUAL.... "AIS Enabled" just means they'll read an AIS statement IF IT COMES IN AT NMEA'S slow baud rate with the rest of the NMEA data. You can't just plug them in, of course. On Lionheart, our current configuration is an SR-161 receiver feeding a Radio Shack RS-232C serial to USB interface cable ($10) plugged into a USB port on the Dell Latitude notebook running the accompanying virtual serial port software so The Cap'n nav software can find the 38,800 baud data stream on what it thinks is a serial port. NMEA system data comes in on another virtual serial port from my wireless router on the NMEA system. The Cap'n regurgitates the AIS data statements at 4800 baud to the NMEA system so it will show up on any instruments capable of reading it. SOME, not all, models of Raymarine and Garmin are capable of reading it from the NMEA stream IF you upgrade their firmware or buy something new. Currently, seeing the ships on the computer display chart is fine...(c; I want to add another Webfoot RS-232C to Ethernet adapter to our Wireless system. When I get that installed, I'm going to feed it the AIS data from the SR-161 receiver. Being on a separate hard-wired Ethernet address on our LAN, I'll be able to connect to its LAN IP address with the second virtual serial port driver that comes with the Webfoot and can eliminate the current Radio Shack hard-wired USB connection AIS is attached to......making both NMEA at 4800 baud and AIS at 38,800 baud available to The Cap'n WIRELESSLY so it will run anywhere on the boat...or even at the yacht club bar if we dock the boat at the club... (c; NMEA out/in 1 4800 baud--Webfoot 1--Netgear wireless router port 1| | AIS SR-161-38.6Kbaud-----Webfoot 2--Netgear wireless router port 2| | RF-wifi radio link--------------| RF-Wifi radio in laptop-|-Virtual serial COM2--The Cap'n NMEA in | |-Virtual serial COM3--The Cap'n AIS in Larry -- http://www.youtube.com/watch?v=fEJmc...elated&search= I'm surprised the Cap'n can pass through (relay) AIS NMEA sentences, but who is going to read them at 4800baud? All equiment that accept AIS do this at 38400. Also, if there is dense AIS traffic, you would soon run into bandwidth problems running at 4800, the very reason why AIS uses 38400. plano |
Portable Gps/Plotter with AIS-Receiver Support
"Bjarke M. Christensen" bjarkeNG@grevestrand_punktum_danmark wrote in message ... Does it make sense ?? It's hard enough already to read the disply on portable units. Adding AIS data on top will just make it totally unreadable. You might be able to read at home, in good light and with you glasses on, but in the boat, dark, raining and in a "windy and critical" situation, you wouldn't be able to see anything .... Bjarke Totally agreed, but what is "portable"? I don't think that there should be any "portable" electronics on a boat. In heavy weather they become missiles or are lost overboard. I cringe when I hear people talk about laptops that can be used "anywhere" on the boat. They should be bolted to the chart table, and by bolted I don't mean kept in place by a piece of shockcord. plano "Pascal" wrote in message ups.com... Anybody knows one? I am using a non portable solution: SR161 + Laptop + GpsMap 276C. I would like to have a gps/plotter portable (or handheld), WeatherProof and useable in the cockpit. I have asked Garmin to give the AIS receiver supprt on the GpsMap 276C but after waiting 2 years I have quit. Thanks Pascal |
Portable Gps/Plotter with AIS-Receiver Support
Yes I have a 5 inch display as well and it is almost workable with AIS.
However have in mind that portable are typical below 2-3 inch display and a 2,5 inch display is only 1/4th of a 5 inch..... I got an eTrex with map support. It's worthless .... Screen is far to small for anything. Portable gps's should telle you yor position and cource to next wpt. Bjarke "Pascal" wrote in message oups.com... Well Bjarke, I have seen the AIS data on a Garmin GpsMap 3205 and I reputed the 5" size very good. Course that the display of targets on a RayMarine C80 I had seen too, is better. All wil depend on the zoom level you set the unit, and I think that in regions with no very heavy traffic like here, if it will show about 10 targets at the 5 nm range, this will be very visible. Anyway, in a critical situation, I could reduce the chart detail on the plotter (declutter) and the best thing will be to hear the alarm and see the ship name, course, speed etc. I have used Ais in my Notebook with SeaClear and ShipPlotter and it is fine, the problem is the size of the laptop, the current drain, the mess of cables etc. And what I want is to have all this information at the helm, not below at the nav table. Regards Pascal On 22 fev, 16:47, "Bjarke M. Christensen" bjarkeNG@grevestrand_punktum_danmark wrote: Does it make sense ?? It's hard enough already to read the disply on portable units. Adding AIS data on top will just make it totally unreadable. You might be able to read at home, in good light and with you glasses on, but in the boat, dark, raining and in a "windy and critical" situation, you wouldn't be able to see anything .... Bjarke |
Portable Gps/Plotter with AIS-Receiver Support
On 22 fev, 20:08, "Bjarke M. Christensen"
bjarkeNG@grevestrand_punktum_danmark wrote: Yes I have a 5 inch display as well and it is almost workable with AIS. However have in mind that portable are typical below 2-3 inch display and a 2,5 inch display is only 1/4th of a 5 inch..... I agree that eTrex with map is useless. By portable I am not talking for anything smaller than a 276C screen (3.8 "), but preferable, something like 5-7 " (Origami/UMPC like, why not?). I do not understand why the resistance to something portable in the boat. I know that there is more than 2 AIS solutions based on Pocket PC (PPC) and I found it very very good, and the only restriction being the lack of weatherproofing in any PPC. And as I told before, I do not think that a map is necessary for use with AIS, a radar like diagram or even the classical street like diagram would be very useful. |
Portable Gps/Plotter with AIS-Receiver Support
"plano" wrote in
: I'm surprised the Cap'n can pass through (relay) AIS NMEA sentences, but who is going to read them at 4800baud? All equiment that accept AIS do this at 38400. Also, if there is dense AIS traffic, you would soon run into bandwidth problems running at 4800, the very reason why AIS uses 38400. plano Listen to your VHF radio tuned to the two AIS channels. The traffic is bursts of data with LOTS of dead time. At some point, you're right, it could become saturated. But 4800 baud would handle the data I've heard coming over the two channels very easily in busy Charleston harbor. Larry -- http://www.youtube.com/watch?v=fEJmc...elated&search= |
Portable Gps/Plotter with AIS-Receiver Support
ppc solutions are for home experiments. My Compaq Ipaq lasted for 2 month in
the boat. Then it was dead. And I wasn't (very) sorry. It was to difficult to read in dayligt due to the glossy screen... Bjarke "Pascal" wrote in message oups.com... On 22 fev, 20:08, "Bjarke M. Christensen" bjarkeNG@grevestrand_punktum_danmark wrote: Yes I have a 5 inch display as well and it is almost workable with AIS. However have in mind that portable are typical below 2-3 inch display and a 2,5 inch display is only 1/4th of a 5 inch..... I agree that eTrex with map is useless. By portable I am not talking for anything smaller than a 276C screen (3.8 "), but preferable, something like 5-7 " (Origami/UMPC like, why not?). I do not understand why the resistance to something portable in the boat. I know that there is more than 2 AIS solutions based on Pocket PC (PPC) and I found it very very good, and the only restriction being the lack of weatherproofing in any PPC. And as I told before, I do not think that a map is necessary for use with AIS, a radar like diagram or even the classical street like diagram would be very useful. |
Portable Gps/Plotter with AIS-Receiver Support
If averaged over 10 minutes or so, maybe 4800 would offer enough bandwidth
in certain locations, but you just cannot risk that say 20 (long) AIS sentences are received more or less simultaneously. There is no way 4800 baud (1/8th!! of 38400) will handle that. Any idea how much traffic one can expect say in the English Channel? It's the worst case scenario that counts, not the average in Charleston harbor. plano "Larry" wrote in message ... "plano" wrote in : I'm surprised the Cap'n can pass through (relay) AIS NMEA sentences, but who is going to read them at 4800baud? All equiment that accept AIS do this at 38400. Also, if there is dense AIS traffic, you would soon run into bandwidth problems running at 4800, the very reason why AIS uses 38400. plano Listen to your VHF radio tuned to the two AIS channels. The traffic is bursts of data with LOTS of dead time. At some point, you're right, it could become saturated. But 4800 baud would handle the data I've heard coming over the two channels very easily in busy Charleston harbor. Larry -- http://www.youtube.com/watch?v=fEJmc...elated&search= |
Portable Gps/Plotter with AIS-Receiver Support
"Pascal" wrote in message
ups.com... Ok, but as I have said, I want a "Portable" unit.. I know that there are many models of gps/ploters that are AIS enabled, like those more recent units from Garmin, Navman, Raymarine, etc but none of them are "portable" (that is, battery operated and easily removable to be used in another boat and at home). What about running an AIS application on a Windows Mobile PDA, inside a waterproof box, using Bluetooth to receive data from an AIS receiver? Meindert |
Portable Gps/Plotter with AIS-Receiver Support
"Larry" wrote in message
... "Pascal" wrote in news:1172160465.780416.309310 @q2g2000cwa.googlegroups.com: I know that there are many models of gps/ploters that are AIS enabled, That all sounds good until you look at what comes out of the AIS at 38,800 baud RS-232 level data....then look at the GPS/Plotters plodding along on RS-422 (NMEA-0183 isn't RS-232C compatible) at 4800 baud..... You need to get your facts straight! A Raymarine C/E series chartplotter runs at 38400 baud when in AIS mode. Most likely others do that too.... Oh and besides that, there is also something called NMEA0183-HS which IS 38400 at RS422. Meindert |
Portable Gps/Plotter with AIS-Receiver Support
What about running an AIS application on a Windows Mobile PDA, inside a waterproof box, using Bluetooth to receive data from an AIS receiver? Meindert I have seen the site of AIS2Ozi software that runs under Ozi/CE in a PPC using a BT adapter, seems very good. By the way, I have put this questions here as a provocation to the builders, so that someone develop the portable AIS that I dream and I would buy it ready to use, at a low price, some time in future ... I would like something the size and format of a Origami/UMPC, a TFT screen of 5-7" with touch screen support, weather proof to be used in the cockpit, and at a cost of a GpsMap 276C, that is, less than 1K, and it will not need to run under Windows/Tablet/XP.... Regards Pascal |
Portable Gps/Plotter with AIS-Receiver Support
I don't think that there should be
any "portable" electronics on a boat. In heavy weather they become missiles or are lost overboard. I cringe when I hear people talk about laptops that can be used "anywhere" on the boat. They should be bolted to the chart table, and by bolted I don't mean kept in place by a piece of shockcord. Having weathered a few sudden storms I agree. If it's not bolted down and designed to be used in heavy weather it really has no place being used for something critical like navigation. Certainly not as the sole provider of such services. As an add-on for use during fair conditions, sure, laptops, PDAs and cell phones are great. But I'd never want to depend on using them when conditions get difficult. |
Portable Gps/Plotter with AIS-Receiver Support
"plano" wrote in
: If averaged over 10 minutes or so, maybe 4800 would offer enough bandwidth in certain locations, but you just cannot risk that say 20 (long) AIS sentences are received more or less simultaneously. There is no way 4800 baud (1/8th!! of 38400) will handle that. Any idea how much traffic one can expect say in the English Channel? It's the worst case scenario that counts, not the average in Charleston harbor. plano You can watch the Irish Sea: http://www.aisliverpool.org.uk/index.php Finest AIS system on the internet. But, of course, YOUR AIS isn't this good. Your range is about 10-12 miles with a 50' antenna listening to these 12W transmitters. This limited range limits the number of AIS packets you must process in your small system. That in itself reduces the load considerably. Click on [Pan and Zoom] on the Liverpool AIS system. Zoom out until the scale in the lower left bottom corner says 10 mi - 20 km on your screen. Now, pan out of the Liverpool ship channel by the docks. Cruise the pan out the channel into the Irish Sea, a busy place out from Liverpool. Go off in the direction of the maximum density of ships you can find at the time. Using the scale in the lower left hand corner as a RADIUS from your boat, the actual range of your own AIS receiver in any at-sea situation, how many ships can you get inside that 40 km circle around your cursor? In Liverpool harbor, with a lot of ships docked but still transmitting away on AIS, I can get, maybe 15 in range. Out at sea, where we are concerned about this problem, the ships are spread out more. If I center my boat 20 km N of Amtwch, the peninsula sticking out to the East of Liverpool, at this moment I would be painting 7 or 8, tops. Point is your boat-mounted AIS receiver's 20 km horizon ISN'T going to paint all those ships you can see on this chart of Liverpool and the Irish Sea, a very busy place for shipping. If 8 ships are transmitting full AIS data into my system on 4800 baud every other second, it won't tax the 4800 baud bandwidth anywhere near its limit to the point where it would jam or nav data packets from the other instruments would be slowed down to a crawl. It just won't happen, unless we put up a 1000' mast to get more packets...... Larry -- http://www.youtube.com/watch?v=fEJmc...elated&search= |
Portable Gps/Plotter with AIS-Receiver Support
"Meindert Sprang" wrote in
: What about running an AIS application on a Windows Mobile PDA, inside a waterproof box, using Bluetooth to receive data from an AIS receiver? Meindert I paid Dell for an Axim X51v, their finest Windows Mobile 5 PDA. I wanted a good PDA to replace my aging Handspring Visor Edge (Palm OS) that someone gave me a while ago. Windows Mobile 5 was a disaster! It would lose control of ITSELF, just sitting there with NOTHING running! The "Today" screen would have WM5's own programs just disappear for no reason. Dell included a program called "Switcher" so you could drop down its menu and switch between running programs that Billy's Boys forgot to put into WM5. Not only would Switcher's menu simply forget what programs were running because WM5 lost control of them, if you left it running a few hours, WM5 forgot where SWITCHER was and lost control of it! Program access from the HOME screen was similarly crashed. Click on one of WM5's own icons to bring up the calendar, for instance, and many times it couldn't boot it because as far as WM5 was concerned IT WASN'T THERE! The cure was always to start over by flipping the X51v on its face and using a pin pressing the RESET button to force a hard reboot. This cure lasted from 20 minutes to 2 hours, when WM5 would, again, crash...... Now, it wasn't my particular X51v. The Dell forums on the subject had hundreds of users with this same phenomenon, lots of crashing. The Dell Kiosk in Northwoods Mall still has a crashing X51v on display. Their cure is to leave the X51v OFF until someone wants to see it run. They can't just leave it running....like you'd want to run nav or AIS software on a boat. Of course, its 3 hour battery life cycle, 30 minutes longer than my Gateway laptop, is another issue altogether. I'm back carrying the Visor Edge. It never crashes and you only have to charge it once a week, even with it running 24/7. Hell, I have two clock programs running on it that chime every hour and alarm all events and that doesn't run its tiny battery discharged, either. Windows Mobile just SUCKS! Larry -- http://www.youtube.com/watch?v=fEJmc...elated&search= |
Portable Gps/Plotter with AIS-Receiver Support
"Meindert Sprang" wrote in
: You need to get your facts straight! A Raymarine C/E series chartplotter runs at 38400 baud when in AIS mode. Most likely others do that too.... Oh and besides that, there is also something called NMEA0183-HS which IS 38400 at RS422. Meindert hMM....We're buying new equipment, again....sorry. What about wonderful NMEA2000, or whatever NMEA is calling their latest and greatest version to sell new equipment this month? Does it run 38,800 baud? I'm still wondering why we don't just make the AIS receivers run 4800 baud. On a boat with a 12 mile range, there aren't enough AIS ships to jam a 4800 baud port up, at least that couldn't be buffered cheaply for a few milliseconds as it spits it out. Do you know why they insist on 38,800 baud RS-232C, not RS-422 levels?? Seems really stupid to me. Larry -- http://www.youtube.com/watch?v=fEJmc...elated&search= |
Portable Gps/Plotter with AIS-Receiver Support
"Larry" wrote in message
... "Meindert Sprang" wrote in : You need to get your facts straight! A Raymarine C/E series chartplotter runs at 38400 baud when in AIS mode. Most likely others do that too.... Oh and besides that, there is also something called NMEA0183-HS which IS 38400 at RS422. Meindert hMM....We're buying new equipment, again....sorry. What about wonderful NMEA2000, or whatever NMEA is calling their latest and greatest version to sell new equipment this month? Does it run 38,800 baud? No, NMEA2000 is CAN based and runs at 250,000 bps. I'm still wondering why we don't just make the AIS receivers run 4800 baud. On a boat with a 12 mile range, there aren't enough AIS ships to jam a 4800 baud port up, at least that couldn't be buffered cheaply for a few milliseconds as it spits it out. First of all, the AIS data transmission speed over VHF already 9600 baud so it would be strange to pack this received data in an NMEA string (more bytes added) and then squeeze it down a 4800 baud channel. Further, a moving ship transmits his info at least once every 10s (0-14kn) to every 2 seconds when between 14-23kn and changing course. So in worst case your receiver gets one AIS message/2s. Each message contains 168 databits, which are packed into 6 bit charachters for NMEA, that is at least 21 chars of AIS data in a VDM sentence. The minimum VDM sentence length is then 43 characters. At 4800 baud, this takes up 89ms so at 4800 baud your AIS receiver would be able to transfer the bare minimum info of 11 ships at a time. Many AIS messages are however longer and can take up to appr. 1000 bits of info, which would result in at least 3 longer VDM sentences per ship. Hence the need for 38400. Do you know why they insist on 38,800 baud RS-232C, not RS-422 levels?? Seems really stupid to me. Yes and no. One would expect a true NMEA0183-HS interface (38,400 at RS422) but most, if not all AIS receivers will be connected to either a computer or a computer based ECDIS. And an simple galvanically isolated intput consisting of an opto-coupler doesn't really care wether the offered signal is RS422 or RS232. Between the wires, there is always the same differential voltage swing of 5-10V in either direction. Meindert |
Portable Gps/Plotter with AIS-Receiver Support
Larry wrote:
"plano" wrote in : If averaged over 10 minutes or so, maybe 4800 would offer enough bandwidth in certain locations, but you just cannot risk that say 20 (long) AIS sentences are received more or less simultaneously. There is no way 4800 baud (1/8th!! of 38400) will handle that. Any idea how much traffic one can expect say in the English Channel? It's the worst case scenario that counts, not the average in Charleston harbor. plano You can watch the Irish Sea: http://www.aisliverpool.org.uk/index.php Finest AIS system on the internet. But, of course, YOUR AIS isn't this good. Your range is about 10-12 miles with a 50' antenna listening to these 12W transmitters. This limited range limits the number of AIS packets you must process in your small system. That in itself reduces the load considerably. If you think Liverpool, UK is a busy shipping area I suggest you think again. Think English Channel, Shanghai, Rotterdam, Singapore for "slightly" busier areas. Also, range at see that I get is a LOT better than 20 km... The big guys tend to have their antenna's pretty high up! (My AIS antenna is a Metz Manta-6 whip mounted 2 m above sea level.) -- Kees |
Portable Gps/Plotter with AIS-Receiver Support
Larry wrote:
"plano" wrote in : If averaged over 10 minutes or so, maybe 4800 would offer enough bandwidth in certain locations, but you just cannot risk that say 20 (long) AIS sentences are received more or less simultaneously. There is no way 4800 baud (1/8th!! of 38400) will handle that. Any idea how much traffic one can expect say in the English Channel? It's the worst case scenario that counts, not the average in Charleston harbor. plano You can watch the Irish Sea: http://www.aisliverpool.org.uk/index.php Finest AIS system on the internet. But, of course, YOUR AIS isn't this good. Your range is about 10-12 miles with a 50' antenna listening to these 12W transmitters. This limited range limits the number of AIS packets you must process in your small system. That in itself reduces the load considerably. Click on [Pan and Zoom] on the Liverpool AIS system. Zoom out until the scale in the lower left bottom corner says 10 mi - 20 km on your screen. Now, pan out of the Liverpool ship channel by the docks. Cruise the pan out the channel into the Irish Sea, a busy place out from Liverpool. Go off in the direction of the maximum density of ships you can find at the time. Using the scale in the lower left hand corner as a RADIUS from your boat, the actual range of your own AIS receiver in any at-sea situation, how many ships can you get inside that 40 km circle around your cursor? In Liverpool harbor, with a lot of ships docked but still transmitting away on AIS, I can get, maybe 15 in range. Out at sea, where we are concerned about this problem, the ships are spread out more. If I center my boat 20 km N of Amtwch, the peninsula sticking out to the East of Liverpool, at this moment I would be painting 7 or 8, tops. Point is your boat-mounted AIS receiver's 20 km horizon ISN'T going to paint all those ships you can see on this chart of Liverpool and the Irish Sea, a very busy place for shipping. If 8 ships are transmitting full AIS data into my system on 4800 baud every other second, it won't tax the 4800 baud bandwidth anywhere near its limit to the point where it would jam or nav data packets from the other instruments would be slowed down to a crawl. It just won't happen, unless we put up a 1000' mast to get more packets...... Larry There is another interesting AIS system overseeing the Kiel canal at http://www.vesseltracker.com/en/kielnok/AreaMap.html You have to register, which is free to individuals. See all the convoys and bottlenecks building up, as and when they occur! Dennis. |
Portable Gps/Plotter with AIS-Receiver Support
I am very happy that many people reply my question which was placed
only in order to remember the manufacturers that there are many users focused in AIS and needing AIS. I think that the big enterprises are not very focused on commercial products with AIS, and may consider AIS a mere fancy for some. I think that Gps/Plotter/Vhf/Ais will be the future, but it seems that it will be much late than sailors desire. |
Portable Gps/Plotter with AIS-Receiver Support
"Meindert Sprang" wrote in
: Hence the need for 38400. Actually, the more you think about it the more the "need" is for Ethernet....for everything. Stupid old serial nonsense just has to stop at some point... You can sell them "marinized routers"....(c; Larry -- http://www.youtube.com/watch?v=fEJmc...elated&search= |
Portable Gps/Plotter with AIS-Receiver Support
"Larry" wrote in message ... "plano" wrote in : If averaged over 10 minutes or so, maybe 4800 would offer enough bandwidth in certain locations, but you just cannot risk that say 20 (long) AIS sentences are received more or less simultaneously. There is no way 4800 baud (1/8th!! of 38400) will handle that. Any idea how much traffic one can expect say in the English Channel? It's the worst case scenario that counts, not the average in Charleston harbor. plano You can watch the Irish Sea: http://www.aisliverpool.org.uk/index.php Finest AIS system on the internet. But, of course, YOUR AIS isn't this good. Your range is about 10-12 miles with a 50' antenna listening to these 12W transmitters. This limited range limits the number of AIS packets you must process in your small system. That in itself reduces the load considerably. Click on [Pan and Zoom] on the Liverpool AIS system. Zoom out until the scale in the lower left bottom corner says 10 mi - 20 km on your screen. Now, pan out of the Liverpool ship channel by the docks. Cruise the pan out the channel into the Irish Sea, a busy place out from Liverpool. Go off in the direction of the maximum density of ships you can find at the time. Using the scale in the lower left hand corner as a RADIUS from your boat, the actual range of your own AIS receiver in any at-sea situation, how many ships can you get inside that 40 km circle around your cursor? In Liverpool harbor, with a lot of ships docked but still transmitting away on AIS, I can get, maybe 15 in range. Out at sea, where we are concerned about this problem, the ships are spread out more. If I center my boat 20 km N of Amtwch, the peninsula sticking out to the East of Liverpool, at this moment I would be painting 7 or 8, tops. Point is your boat-mounted AIS receiver's 20 km horizon ISN'T going to paint all those ships you can see on this chart of Liverpool and the Irish Sea, a very busy place for shipping. If 8 ships are transmitting full AIS data into my system on 4800 baud every other second, it won't tax the 4800 baud bandwidth anywhere near its limit to the point where it would jam or nav data packets from the other instruments would be slowed down to a crawl. It just won't happen, unless we put up a 1000' mast to get more packets...... Larry -- http://www.youtube.com/watch?v=fEJmc...elated&search= Short summary: A 4800 bps NMEA link may very well overflow in not-insanely-busy conditions. Explanation follows: A couple of weeks ago I sailed out of Sausalito to see the Queen Mary 2 enter San Francisco Bay. While still in the slip, I saw over 75 simultaneous AIS targets, out to about a 25 NM range. My antenna for the AIS receiver is just a 6dB (short) whip, mounted on the stern rail, so with a masthead antenna the range (and number of ships seen) would have been much greater. I don't know what the burst data-rate was, but let's assume that on the average each ship is transmitting a "dynamic information" message-type at 10-second intervals (2 seconds is the fastest update-rate, 12 seconds is the slowest rate for a ship under way) Ignoring the less-frequent "Static" messages, each message is 256 bits (a "dynamic" message is 168 bits, plus 88 bits of overhead). The radio-channel bit-rate is 9600 BPS (from the AIS spec). I don't know how well the timeslot-assignment method fills the available slots, but the maximum would be about 375 active ships (256 bits every 10 seconds, times 375 ships = 9600 BPS). A "dynamic" message gets encapsulated into a 47-character NMEA message. This is 517 bits (each ASCII character is 8-bits + start-bit + two stop-bits = 11 bits). 375 active ships, each transmitting one message every 10 seconds would create an NMEA serial data stream of 37.5 * 517 = 19387.5 BPS. Either this is a coincidence, or my math is about right. A 19.2 kbps link should be able to handle full-capacity AIS. It would only take about 93 active ships to fill a 4800 BPS NMEA link, and this assumes even spacing of the messages, or very deep buffers. I can easily see overrunning the capacity of a 4800BPS link, especially if I had a mast-top antenna. I have a dual-channel receiver, but having one of the single-channel receivers should cut these data rates in half. -Paul |
Portable Gps/Plotter with AIS-Receiver Support
Paul wrote:
snip Short summary: A 4800 bps NMEA link may very well overflow in not-insanely-busy conditions. Explanation follows: A couple of weeks ago... snip Paul, Thank you for your most excellent report and very coherent explanation. It was wonderful! Jack -- Jack Erbes in Ellsworth, Maine, USA (jackerbes at adelphia dot net) (also receiving email at jacker at midmaine dot com) |
Portable Gps/Plotter with AIS-Receiver Support
"Paul" wrote in
: It would only take about 93 active ships to fill a 4800 BPS NMEA link, and this assumes even spacing of the messages, or very deep buffers. You can see 90 ships on AIS from a stern rail antenna? How do you plot these so it doesn't destroy the other navigation? The stern rail antenna to a ship antenna 100' up would only have a range of 10 miles. Ok, we can load up the crappy NMEA 1966 data link. I'll say "uncle". All the more reason the whole damned boat should be on ethernet. But, alas, how many pleasure boaters ever see 20 ships painted on an AIS display? I doubt it's very many. I feel sorry for those who have to sail in those conditions, just like boaters on the ICW in Florida stuck in a ditch so dense with boats noone can ever have a fun time. We South Carolinians need to look at ourselves, once in a while, and see how lucky we are to be able to sail around and never see another boat for hours, certainly not one that crosses our paths....lucky indeed. Larry -- http://www.youtube.com/watch?v=fEJmc...elated&search= |
Portable Gps/Plotter with AIS-Receiver Support
"Larry" wrote in message
... You can see 90 ships on AIS from a stern rail antenna? How do you plot these so it doesn't destroy the other navigation? The stern rail antenna to a ship antenna 100' up would only have a range of 10 miles. Theoretically yes, but there's also refraction of the VHF signals around the "edge" of the earth that makes the signals go further. You as a ham should know that. Ok, we can load up the crappy NMEA 1966 data link. I'll say "uncle". All the more reason the whole damned boat should be on ethernet. But, alas, how many pleasure boaters ever see 20 ships painted on an AIS display? I doubt it's very many. I feel sorry for those who have to sail in those conditions, just like boaters on the ICW in Florida stuck in a ditch so dense with boats noone can ever have a fun time. Cross the English channel and find out for yourself how busy it is. Or the Solent area. We South Carolinians need to look at ourselves, once in a while, and see how lucky we are to be able to sail around and never see another boat for hours, certainly not one that crosses our paths....lucky indeed Yeah, you South Caronlinians are a bunch of pussies compared to the guys who regularly cross the English Channel... ;-)) Meindert |
Portable Gps/Plotter with AIS-Receiver Support
"Larry" wrote in message ... "Paul" wrote in : It would only take about 93 active ships to fill a 4800 BPS NMEA link, and this assumes even spacing of the messages, or very deep buffers. You can see 90 ships on AIS from a stern rail antenna? How do you plot these so it doesn't destroy the other navigation? The stern rail antenna to a ship antenna 100' up would only have a range of 10 miles. Ok, we can load up the crappy NMEA 1966 data link. I'll say "uncle". All the more reason the whole damned boat should be on ethernet. But, alas, how many pleasure boaters ever see 20 ships painted on an AIS display? I doubt it's very many. I feel sorry for those who have to sail in those conditions, just like boaters on the ICW in Florida stuck in a ditch so dense with boats noone can ever have a fun time. We South Carolinians need to look at ourselves, once in a while, and see how lucky we are to be able to sail around and never see another boat for hours, certainly not one that crosses our paths....lucky indeed. Larry Larry and Jack, I took a detailed look at my NMEA logfile to see if I could sanity-check last night's calculations. It turns out that what I actually was receiving is fairly close to the estimates -- but not quite as bad: (and I lied -- on-board VALIS I have a SR-161 single-channel receiver. The two-channel receiver is at home for the time being, as part of my development platform) During a ten-minute period on the Bay, just inside of the Golden Gate Bridge, I received signals from 76 ships (a few of these were actually base-stations). The maximum range was 21 statute miles, but remember that the surrounding hills are pretty high in most directions. About half of the ships were moored. During this ten minutes there were 1401 AIVDM (AIS) NMEA sentences sent from the AIS receiver, totalling 68581 bytes, or 754391 bits. This gives an average datarate of 1257 bps. Using a dual-channel AIS receiver the rate would double to 2515 bps. So, perhaps, even with the burstiness of the data, a 4800bps NMEA link would work -- but the margin isn't comfortable, and I have to think that with a mast-top antenna I might easily exceed the link capacity. In any case, it sounds like we all agree that 4800bps serial is not the shining path to the future! I am displaying the AIS targets on my PocketPC, which is usually velcro'd to the navstation next to the chartplotter. I have a Bluetooth link from the AIS receiver and the NMEA mux which carries the rest of the nav-data. My Raymarine RL70 and RL80 chartplotters (now obsolete) don't support AIS, thus the PocketPC. The PPC, running a program I wrote, has a display (for AIS) that looks more or less like the NASA "AIS Radar", with no chart overlay. It still gets pretty crowded, but I can turn off ship name display and then it is usable during crowded conditions. The PPC calculates CPA, TCPA, sounds an alarm if appropriate, etc -- all the stuff that I expect my new chartplotters to do well, on a much larger screen. The PPC program also shows other nav data, using dials, numeric displays, etc. I mainly use it as a "black box" to log filtered nav and AIS data, so I can postprocess it later and remind myself (when I am programming) of how much I enjoy sailing. I have some interesting (to me, at least) Google-Earth tracks created from the PPC logfiles, posted on the VALIS blog: http://www.sailvalis.com/wordpress_1/ . The most recent posting has the tracks for VALIS and the AIS-equipped ships heard during the Queen Mary 2 excursion. I use the PPC rather than a laptop for this in order to keep the power consumption under control. -Paul |
Portable Gps/Plotter with AIS-Receiver Support
Thank you for sharing this info with us ... Very interesting and
impressive visualization! Unfortunately, I have some older Raymarine equipment (RC530+) , that is not compatible with any AIS-system, that I know of. Would you know, if this is correct? If you should recommend a well working AIS-system that can be used on a notebook running Windows XP ... What would be your advice? - Software and hardware? Pls note I run the RNS-5 application on the notebook using C-Map charts, and I sail in Scandinavian waters (12V-DC/230V-AC) - if that is of any importance for your advice. TIA! -- Flemming Torp Gimle/DEN-61 "Paul" skrev i en meddelelse ... SNIP Larry and Jack, I took a detailed look at my NMEA logfile to see if I could sanity-check last night's calculations. It turns out that what I actually was receiving is fairly close to the estimates -- but not quite as bad: SNIP The PPC, running a program I wrote, has a display (for AIS) that looks more or less like the NASA "AIS Radar", with no chart overlay. It still gets pretty crowded, but I can turn off ship name display and then it is usable during crowded conditions. The PPC calculates CPA, TCPA, sounds an alarm if appropriate, etc -- all the stuff that I expect my new chartplotters to do well, on a much larger screen. The PPC program also shows other nav data, using dials, numeric displays, etc. I mainly use it as a "black box" to log filtered nav and AIS data, so I can postprocess it later and remind myself (when I am programming) of how much I enjoy sailing. I have some interesting (to me, at least) Google-Earth tracks created from the PPC logfiles, posted on the VALIS blog: http://www.sailvalis.com/wordpress_1/ . The most recent posting has the tracks for VALIS and the AIS-equipped ships heard during the Queen Mary 2 excursion. I use the PPC rather than a laptop for this in order to keep the power consumption under control. -Paul |
Portable Gps/Plotter with AIS-Receiver Support
"Flemming Torp" fletopkanelbolle2rp.danmark wrote in message
. .. Thank you for sharing this info with us ... Very interesting and impressive visualization! Unfortunately, I have some older Raymarine equipment (RC530+) , that is not compatible with any AIS-system, that I know of. Would you know, if this is correct? If you should recommend a well working AIS-system that can be used on a notebook running Windows XP ... What would be your advice? - Software and hardware? Pls note I run the RNS-5 application on the notebook using C-Map charts, and I sail in Scandinavian waters (12V-DC/230V-AC) - if that is of any importance for your advice. TIA! Just across the water from where you live is a company called Seacom (Egersund, NO). They make and sell Winchart. This software does AIS and uses C-Map charts. A good AIS receiver would be the SR-161. They might be able to supply the receiver too and if not, I can for EUR 199 incl. Dutch VAT. Meindert www.shipmodul.com |
Portable Gps/Plotter with AIS-Receiver Support
Hi Flemming,
1) Softwa I think that If you have RN5, could be that you can upgrade to RN6 for free? And maybe RN6 already support AIS or no? Another option is SOB (Software On Board) from Digiboat which supports C-Map charts too and could be free or very cheap ... In any case you could install SeaClear (very good free software) to make the initial tests using raster BSB or Nos/Geo Charts, and it supports home scanned charts too. 2) Hardwa both Smart Radio SR161 and EasyAis are very good Ais receivers, you should consider a VHF antenna splitter for ease installation and good reception, and perhaps you could use the "AirCable" Bluetooth Serial/Usb adapters to eliminate cables as suggested here from someone in the beginning. Regards Pascal ..... should recommend a well working AIS-system that can be used on a notebook running Windows XP ... What would be your advice? - Software and hardware? Pls note I run the RNS-5 application on the notebook using C-Map charts, and I sail in Scandinavian waters (12V-DC/230V-AC) - if that is of any importance for your advice. TIA! -- Flemming Torp Gimle/DEN-61 |
Portable Gps/Plotter with AIS-Receiver Support
"Meindert Sprang" skrev i en meddelelse ... "Flemming Torp" fletopkanelbolle2rp.danmark wrote in message . .. Thank you for sharing this info with us ... Very interesting and impressive visualization! Unfortunately, I have some older Raymarine equipment (RC530+) , that is not compatible with any AIS-system, that I know of. Would you know, if this is correct? If you should recommend a well working AIS-system that can be used on a notebook running Windows XP ... What would be your advice? - Software and hardware? Pls note I run the RNS-5 application on the notebook using C-Map charts, and I sail in Scandinavian waters (12V-DC/230V-AC) - if that is of any importance for your advice. TIA! Just across the water from where you live is a company called Seacom (Egersund, NO). They make and sell Winchart. This software does AIS and uses C-Map charts. A good AIS receiver would be the SR-161. They might be able to supply the receiver too and if not, I can for EUR 199 incl. Dutch VAT. Meindert www.shipmodul.com Thank you very much Meindert. Very useful. I have already been to their homepage. My only "concern" is, that I have to invest (time & money) in one more navigation application ... I have already invested in RNS-5, Maptech's Offshore Navigator, and a Danish Package, called "The Living Sea-map" .... But I can not find any of these on an "AIS-compatibility list" ... (I wonder why, as the two first mentioned systems come from pretty large suppliers ?...). But I understand your answer like this: There is no alternative to installing one more software package on my PC, if I want to integrate AIS and C-Map charts on my notebook - right? Do you have any idea of the possibility of using (i.e. getting access to) the C-Maps when they are placed in the Raymarine chartplotter with a hsb2 interface to the notebook PC running the Winchart application? Normally, I run the RNS 5 application on the PC with the C-Map charts residing in the chartplotter (C530+), but I'm not sure whether another application will get access to the C-Map charts? Do you know anything about this? I wish, the Dutch VAT would suffice ... ;o) ... In Denmark the VAT is 25% ... It is, however, often possible to purchase things like that from Germany or UK at reasonable prices ... incl. VAT + CIF. I will look further into info about the SR-161 in the coming days. Do you see any problems (technical/safety) in using a VHF antenna splitter supplying my FM radio, the VHF and the AIS-receiver - may be even a DVB-T antenna? Thank you for your help. -- Flemming Torp Gimle/DEN-61 |
Portable Gps/Plotter with AIS-Receiver Support
Hi Pacal,
"Pascal" skrev i en meddelelse ups.com... Hi Flemming, 1) Softwa I think that If you have RN5, could be that you can upgrade to RN6 for free? And maybe RN6 already support AIS or no? When I asked the Danish importer of Raymarine, I was informed, that the major difference between RNS.5 and RNS.6 was the support of Navionics charts in the new release ... As I'm using C-Map charts, in don't think ver. 6 is relevant for me ... Another option is SOB (Software On Board) from Digiboat which supports C-Map charts too and could be free or very cheap ... In any case you could install SeaClear (very good free software) to make the initial tests using raster BSB or Nos/Geo Charts, and it supports home scanned charts too. Good idea! I have now downloaded the Australian system -SOB -, and using my C-Map card reader, I have tried to run this system on my PC (in simulation mode, that is, as the boat is on land and almost covered by snow ...), and SOB reads my C-Map cassettes without problems. Seems to be a very user friendly package with all the facilities I need ... and from the cocumentation, I can see, the system supports AIS ... Very interesting ... 2) Hardwa both Smart Radio SR161 and EasyAis are very good Ais receivers, you should consider a VHF antenna splitter for ease installation and good reception, and perhaps you could use the "AirCable" Bluetooth Serial/Usb adapters to eliminate cables as suggested here from someone in the beginning. Based on yours and Meinderts response (and Bjarkes comment ...), SR161 or EasyAIS seems to be the "winners" ... I'm unfortunately a complete amateur, when it somes to electricity/cabling etc. ... As my notebook PC (close to the VHF) is hidden in the chart table controlling a remote monitor, visible from the cockpit, I may not need BT - and the inherent problems ... right? I can control the application from the cockpit using a wireless/remote mouse. Is the use of a VHF antenna splitter "safe"? ... I have heard some "warnings", that in case of a malfunction of the splitter, you run the risk of destroying the AIS receiver when using the VHF sender? Or is it just nonsense? ... Regards Pascal Regards, and thank you so much for your help! -- Flemming Torp Gimle/DEN-61 |
Portable Gps/Plotter with AIS-Receiver Support
Flemming, I can see that your boat is very well equipped... I suggest strongly that you give a visit to the web page of another sailor very well equipped and very well documented ... It has a excellent home page with interesting information about his experience with AIS and specially with SOB... See the link below: http://www.svsarah.com/Sarah/Upgrades/AIS.htm Pascal |
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