Radar recommendation

[Ballsnall]

Originally Posted by Leighpilot

You state that you want to install a navigation system, starting with a radar. That’s a problem. Radar isn’t a navigation system. Or even part of one. It’s at best an aid to navigation.

Our navigation lecturer at the Merchant Navy Academy was very insistent on radar only being an aid to navigation, not a means of navigation.

I would suggest that is your lecturer's opinion, and not fact. You certainly can navigate with radar very accurately using range and bearing and prior to GPS was by far the best and most commonly used coastal navigation system on commercial vessels and is still a fast and accurate way to get an exact fix. I would be very comfortable navigating on a vessel with only a radar & chart and have done many times in very tricky waters day and night.

[Leighpilot]

You mention “ prior to GPS” as a reason for navigating by radar. We now have GPS which is cheaper , more accurate , more reliable and uses less power than a radar. Which makes it a bit odd to be advocating radar as a navigation system in a world with GPS.

So now we’re facing that all too common dilemma in modern life. Do we trust the advice of a qualified doctor or a guy with three hours of research on YouTube? Or as in this case , do we trust the opinion of a qualified and experienced Merchant Navy Academy navigation lecturer or some guy with unknown credentials? For me , both are easy choices to make. Others might chose differently.

My own experience leads me to believe that you simply haven’t had enough experience at sea in areas with low lying coastlines or extensive off lying hazards where radar is not a viable aid to navigation. A reliance on radar in areas like that will almost certainly result in an insurance claim.

My experience and training leads me to believe that a chart plotter , GPS , updated charts and an echosounder would be a safer , more reliable and more cost effective navigation system than a radar. I have no dog in this fight as I don’t sell these th8ngs and the OP is free to decide which advice to take.

[Ballsnall]

Ouch!

[Corsair63]

One session of the IMO MSC (not so long ago when Manila Amendments were discussed) regarding the minimum requirements for navigation officers (OOW II/1 or Master/Mate II/2) one nation with huge representation and fleet (Norway) asked to commission remove from the compulsory syllabus the astronomical theory/calculations when all commercial vessels have GNSS.
well the answer was not surprising but who did it, yes, USA said a very explanatory and short one:

GPS is a military system and we have the switch.

same happens with GLONASS, also Beidu and I don't know the policy of Galileo.

in crisis areas not so long ago I've sailed in places where is not available the GPS either the position are jumping continuously (*). also NMEA connection of RADAR is not too old, and yes, former times with neither TRANSIT (previous version of GPS, only one or two satellite positions a day) nor GNSS, the only navigation & anti-collision trusty system was the RADAR.

GNSS are very user friendly but it must be "surveyed" for results, in our case when we have vetting inspection by Oil Majors when must have a back-up and records of double check by another means, e.g. RADAR, astronomical navigation, etc. GNSS are not considered as "safe by itself" navigation systems.

also the limitation of GPS, it transmit two messages/frequencies named as: Code P & Code C/A, we as civil user we're receiver of only one C/A and if I remember 99% of position are in a radius of 100 metres (if not interfered by defense needs). US military and defined allied user also receive P this is the one that is not interfered and gives a huge accuracy, but none of us are receivers of such code, is a restricted code.
(*) Adriatic sea while the war in former Yugoslavia and later NATO blockage, Coast of Yemen since 2006 and up, and you should know or sail in another places too.

C/A: Civilian Access code.

some info: https://www.e-education.psu.edu/geog862/node/1741

[goboatingnow]

Originally Posted by Corsair63

One session of the IMO MSC (not so long ago when Manila Amendments were discussed) regarding the minimum requirements for navigation officers (OOW II/1 or Master/Mate II/2) one nation with huge representation and fleet (Norway) asked to commission remove from the compulsory syllabus the astronomical theory/calculations when all commercial vessels have GNSS.
well the answer was not surprising but who did it, yes, USA said a very explanatory and short one:


same happens with GLONASS, also Beidu and I don't know the policy of Galileo.

in crisis areas not so long ago I've sailed in places where is not available the GPS either the position are jumping continuously (*). also NMEA connection of RADAR is not too old, and yes, former times with neither TRANSIT (previous version of GPS, only one or two satellite positions a day) nor GNSS, the only navigation & anti-collision trusty system was the RADAR.

GNSS are very user friendly but it must be "surveyed" for results, in our case when we have vetting inspection by Oil Majors when must have a back-up and records of double check by another means, e.g. RADAR, astronomical navigation, etc. GNSS are not considered as "safe by itself" navigation systems.

also the limitation of GPS, it transmit two messages/frequencies named as: Code P & Code C/A, we as civil user we're receiver of only one C/A and if I remember 99% of position are in a radius of 100 metres (if not interfered by defense needs). US military and defined allied user also receive P this is the one that is not interfered and gives a huge accuracy, but none of us are receivers of such code, is a restricted code.
(*) Adriatic sea while the war in former Yugoslavia and later NATO blockage, Coast of Yemen since 2006 and up, and you should know or sail in another places too.

C/A: Civilian Access code.

some info: https://www.e-education.psu.edu/geog862/node/1741

You need to be careful quoting stuff you haven’t read


C/A without selective availability provides at least +- 20 metres with 99 % probability and that’s before adding SBAS which can deliver < 5m accuracy reliably. Aggregation across multiple GNSS can reduce probability errors. All current GNSS systems provide SBAS

Secondly with the huge civilian reliance on such systems GNSS system will not be arbitrarily disabled and too much US and allies military systems actually rely on C/A

Galileo is a good bit more accurate ( <1m) then GPS and is a civilian controlled system to boot

Hence given everything , we can rely on GNSS , if it ever disappears we will have far more concerns then worrying about leisure boat navigation. Celestial isn’t much use in a nuclear winter !!!

GNSS is a relied upon primary navigation tool and rightly so.

Note that Galileo high accuracy service ( cm level accuracy ) is not encrypted and freely available ( the link provided by the OP is dated and wrong ) hence sophisticate receivers can achieve extremely accurate positioning , well beyond the accuracy of seabed mapping

Bogey man issues about GNSS completely suddenly disappearing are just that.

[Leighpilot]

Oddly enough I just had this discussion with another sailor.

I came to the same conclusion. If GPS etc is switched off , we’re in a worldwide nuclear war and getting safely to home port is the least of your worries then.

[Bobby Lex]

Navigation starts with charts (paper or electronic). Then a depth sounder. Radar is down the list somewhere. I just find it odd that the OP wants to start with radar and build his navigation system around that.

Radar can tell you that there is something out there. But you don't know where "there" is without a chart.

Bob

[Anders]

Originally Posted by Bobby Lex

Navigation starts with charts (paper or electronic). Then a depth sounder. Radar is down the list somewhere. I just find it odd that the OP wants to start with radar and build his navigation system around that.
Bob

This is in the OpenCPN forum and I assume that he use or will use OpenCPN.

[Corsair63]

You need to be careful quoting stuff you haven’t read

I think this statement is a bit daring, I'm going to take it with the greatest sense of humor possible, thinking that it has been a response in the heat of battle.

Of course, since I left the University, many things have changed and one of them is the accuracy of the system itself, without using either differential GPS (based on ground radio stations) or the system that is replacing it, SBAS. now:
• 2.5 meters in 95% of the time.
• with a DGPS system called SBAS (WAAS-EGNOS-MSAS), being less than one meter in 97% of cases.
• Note that much of the southern hemisphere does not have SBAS coverage, so there are no GNSS position corrections.

The Selective availability, forgive me for saying, but I don't believe it, I've suffered it and well after 2002, the GPS receiver being crazy jumping in certain areas.

If GPS etc is switched off , we’re in a worldwide nuclear war and getting safely to home port is the least of your worries then.

Not needed, I’ve sailed around conflict areas where you haven’t GPS signal and I understand that is logical.


But returning to the subject in question, I think that a more than remarkable installation could be and as I see it not excessively expensive :

1. RADAR compatible with OpenCPN
2. AIS transceiver (Maiana is a good example of Opensource), being a transceiver, it has a GNSS receiver included (as I remember at least GPS, GLONASS and Galileo)
3. A good echo sounder.
4. Of course a computer, I don't know how to express in English “No me mojo” neither recommend anyone in special, because I haven't had good experiences with on-board computers and I have two burned, so I recommend that they’d be connected, in principle, to a stabilized and rectified DC source (12 volt)

now supposed that could be another keywork the interfacing among systems:
I've a Shipmodul NMEA 183/N2K/wired network this last is the connection of the computer (at last arrived today), lets say difficult to say which option.
if you have previous hardware with NMEA 0183 that should be the option, bearing in mind sometimes complicated comms computer > device. because most of these multiplexers had only unidireccional comms device > computer.
if you have nothing on board you can go to N2K that there is bidirectional comm and maybe you won't need the multiplexer because there are in the market adaptors N2K > USB and your computer will be inside the N2K network, also it's easier to develop the wiring on board.
about Signal K, I cannot tell you so much, it's opensource but I never worked with it, something to study in the near future about.

Bidireccional NMEA comms on board, some of them, I cannot have mental records of all them:

• AIS transceivers (receivers don't needed it)
• RADAR data exchanges
• GNSS, in order calculate itself and receive feedback of waypoint and routes from user.
• Auto-pilot, otherwise it won't receive steering orders.

Some useful links as Info only, of course for all of us in general, not technical publications:
Spanish: GPS - Wikipedia, la enciclopedia libre
English: Global Positioning System - Wikipedia
SBAS system Spanish: SBAS - Wikipedia, la enciclopedia libre
SBAS system English: GNSS augmentation - Wikipedia

[Leighpilot]

To be fair , the OP admits he’s new to the game and radar seems pretty magic. I’m hoping he will get some instruction in nav etc before heading out. And that he’s sensible enough to discern and take good advice.

[goboatingnow]

Originally Posted by Leighpilot

Oddly enough I just had this discussion with another sailor.

I came to the same conclusion. If GPS etc is switched off , we’re in a worldwide nuclear war and getting safely to home port is the least of your worries then.

Yes indeed hard to sail when the sea has turned to glass !!

[Baby tug]

Originally Posted by Leighpilot

You state that you want to install a navigation system, starting with a radar. That’s a problem. Radar isn’t a navigation system. Or even part of one. It’s at best an aid to navigation.

Better start with a chart plotter , echosounder and an AIS. ( yes AIS isn’t a navigation item but it’ll do what a radar will do in most cases ). To navigate with a radar you’d have to take bearings and distances off prominent shore features. The problem with that is that often a coast line has none or sometimes you’ll be getting what looks like a coast return but is actually a return from hills or mountains further inland if the coastline is low lying. Which will lead you astray.

Our navigation lecturer at the Merchant Navy Academy was very insistent on radar only being an aid to navigation, not a means of navigation. So go get yourself a good chart plotter , echosounder and an AIS transponder. Most boats will be transmitting an AIS signal and they’ll then show up on your chart plotter where you can easily see their details , speed, course , size etc. Even their MMSI number so you can call them to coordinate course changes etc if needed.

And get some experienced crew , formal training before you go out. You can die doing this stuff.

Couldn’t agree more that’s basically what I was trying to say on page one , I quit using radar years ago , I personally think it’s outdated technology well that’s my opinion if you like radar use radar, I think you should put it on top of your bicycle helmet when you ride your bicycle

[skipmac]

Originally Posted by Baby tug

Couldn’t agree more that’s basically what I was trying to say on page one , I quit using radar years ago , I personally think it’s outdated technology well that’s my opinion if you like radar use radar, I think you should put it on top of your bicycle helmet when you ride your bicycle

Outdated?

You ever go boating in a heavy fog? Radar is pretty handy in that situation.

[dannc]

GPS can be spoofed or jammed, and has been spoofed or jammed in the last year or so off the north coast of Norway, Baltic near Finland and China. I would guess the Black Sea might be a bit "interesting" at the moment.

I have seen my GPS do some wacky things and I was not in an area of conflict.

One does not need a limited or full exchange of nukes to degrade satellite based navigation systems.

Later,
Dan

[Alaska JD]

This winter I installed a Halo 20+. I connected it to my Simrad NSS12. I love it! It has wonderful resolution. I can easily see crab pot buoys at 100’ on reasonably calm water. It keeps me well apprised of any targets that are relevant to my course. I’m still learning how to use/harvest all of information it can provide.