I was watching a clip of a airplane landing on a small island surrounded by many ships which got me wondering. Are there, or were there ever any navigation aids that both airplanes and ships could use?
At airports like London City Airport, do they use a common com frequency for ships and airplanes? I only assume that it woudn't be wise for a sailship to pass the end of the runway with an Avrojet spooling up four engines for take off :p

Currently: GPS

Formerly (at least in the U.S, anyhow) : LORAN

Formerly: Celestial

And as a backup in both cases, Pilotage.

[Edited 2011-02-28 04:39:26]

To add to the list above, I think DECCA was also used as used in both aviation and ships.

A Compass…

Yes I know that is a bit facetious, but it is true.

Quoting RoseFlyer (Reply 3):

Let's add stars as a glimpse of history as well  

Medium wave radio beacons using the ADF

Jan

Ambrose lightship outside NY harbor used to be a radiobeacon on the aero charts-- maybe it still is. Must be other NDBs that ships and aircraft both use?

Quoting Northwest727 (Reply 2): I think DECCA was also used as used in both aviation and ships.

The DECCA Navigator was designed for ships, but widely used by aircraft.
It was the driver of the moving map display on the dH Trident in the 1960's.
The DECCA chain covered most of Europe, and the East coast of the USA.

Maybe the question is what aircraft nav systems are NOT used by others means of transport? Light beacons and VOR/DME/TACAN? (are all of those manifestations of the same thing?)

Quoting MD11Engineer (Reply 5): Medium wave radio beacons using the ADF Jan

I was going to say that myself. Port Angeles, WA, USA featured a dual-use NDB beacon at one point, attached to the Coast Guard air station  

I am always so amazed at how knowledegable people on this forum are. I had to goole a lot of new words (DECCA what? :P )

Interesting to hear that quite a few navaids were used by both airplanes and boats. But I always thought that boats couldn't make use of NDBs and VORs since they would be too low to capture the signals,

I once read in these forums someone (or someone who knew someone) who is/was a pilot and used, just for fun, sextants on their Atlantic crossings. This was a while ago so details are fuzzy, but supposedly it was relatively accurate, predicting landfall on the other side by just a couple of miles.

I only remember this because I thought to myself if I was a pilot, that would be something cool to do.

Quoting PPVRA (Reply 11): I once read in these forums someone (or someone who knew someone) who is/was a pilot and used, just for fun, sextants on their Atlantic crossings.

For quite a while before, during, and for a time after WWII long distance (over ocean) flying relied on sextants. Ernest Gann talks about it in "Fate is the Hunter."

LORAN-A then LORAN-C was originally designed for ships and then it was adapted for aviation use. Now it's been decommissioned.

The shipboard equivalent to NDBs was the radio beacon and ships use a RDF (radio direction finder) to use it. But radio beacons are rare things these days. They were used to transition from open ocean navigation to coastal piloting.

Ships do use GPS but once you get in confined waters it's not accurate enough for general usage, just like GPS is not accurate enough for aircraft to use in the terminal areas and for approaches. Aircraft use a space based augmentation (WAAS in the US) ships use ground based augmentation-differential GPS. The system is installed at all commercial ports and harbors in the US.

Once a ship gets in confined waters the means of navigation are visual piloting and navigation/dead reckoning plot, radar nav, and differential GPS. Celestial is still done but in open ocean navigation in conjunction with basic GPS and the dead reckoning plot.

Comm wise ships use a different frequency band - the marine band (go figure) and can't access aviation frequencies just like aircraft cannot access the marine band. Ships don't tune radios like airplanes do. Instead they switch channels. Channel 16 is the international hailing and distress frequency. It is like 156.8MHz or something like that. In the US channel 13 is used. If you want to talk to another ship you hail it on channel 16 and then switch to another channel that you can agree on.

That doesn't prohibit a ship from having an aviation radio to talk to airplanes or an airport tower from having a marine radio. The difference is that a marine frequency is an open freq there is no control agency who is in charge of the freq. If you can talk on it you do- it's more like a unicom or ctaf. Whereas is you tried to talk on tower or ground for non tower or ground related things the tower controller or ground controller would squash you.
Having a

Quoting woodreau (Reply 13): ust like GPS is not accurate enough for aircraft to use in the terminal areas and for approaches.

Quite the contrary. Even non-WAAS aircraft with IFR certified GPSs can navigate in terminal areas and perform (non-precision) approaches. The only difference with WAAS is that you can do CAT I/glidepath approaches. WAAS is designed to give you accuracies better than 10ft. A non augmented GPS signal is good for 45ft accuracy on average, and it's normally much better than that.

Quoting aklrno (Reply 8): NOT used by others means of transport? Light beacons and VOR/DME/TACAN?

Light beacons can be argued, since boats use a lot of lighted nav aids. I mean a light house is the same thing as a rotating beacon without the green light.

On another note, in Alaska (Im sure its the same in a lot of other places as well) the float plane pilots use nautical charts and most of them have a marine radio on board.

Quoting SEPilot (Reply 12): For quite a while before, during, and for a time after WWII long distance (over ocean) flying relied on sextants.

QFs B707-338s had domes in the cockpit roof to allow for sextant use. They also carried navigators until well towards the end of B707 operations, especially to South Africa.

Gemuser

Quoting Dainan (Thread starter): Are there, or were there ever any navigation aids that both airplanes and ships could use?

I think Omega could be used by anybody...ships and aircraft included, although I can't swear that both actually did it.

Tom.

I can think of one form of marine navigation that never quite made it into aviation. The ancient Polynesians could navigate over vast distances of open ocean by "reading" wave types and currents. That is like flying from Dallas to Chicago by recognizing individual clouds

Quoting woodreau (Reply 13): Ships do use GPS but once you get in confined waters it's not accurate enough for general usage, just like GPS is not accurate enough for aircraft to use in the terminal areas and for approaches

This is incorrect, as GPS can be used in the terminal area and for approaches. Don't believe me? Have a look for yourself:

AIM 1-1-19: http://www.faa.gov/air_traffic/publi...pubs/AIM/Chap1/aim0101.html#1-1-19

Garmin GNS 430A manual: http://www8.garmin.com/manuals/GNS430_PilotsGuide.pdf

GPS Approach

Quoting gemuser (Reply 16): QFs B707-338s had domes in the cockpit roof to allow for sextant use. They also carried navigators until well towards the end of B707 operations, especially to South Africa.

BOAC VC-10s had a port on the upper fuselage (between the navigator and flight engineer's seat) in which a sextant could be inserted and used, and removed if needed. You can see it in this photo protruding from the ceiling right in the middle of the frame:

VC-10 cockpit. Photo source: www.vc-10.net

[Edited 2011-03-01 06:19:52]

[Edited 2011-03-01 06:25:18]

Quoting aklrno (Reply 8): Light beacons

Light beacons were used extensively during the late 1920s up to the 1940s to mark airways and airfields. Even today almost all airfields have a rotating light beacon (white flashing for civilian airports, green-white for military ones).

Quoting woodreau (Reply 13): Channel 16 is the international hailing and distress frequency.

this is VHF shortrange ship to ship or ship to shore only. 2.182 MHz USB is the international SSB HF hailing and distress frequency and has (especially at night) a much greater range than VHF. I live quite far away from the coast, but if I tune my HF receivers to this frequency, I can easily receive calls from Ireland to the Mediterranean (even with my mediocre antenna).

It used to be 500 KHz for CW (Morse code) transmissions, but practically all countries have stopped using this service about ten years ago (I think China is still providing coastal radio service in Morse code).

Jan

Quoting alaska737 (Reply 15): On another note, in Alaska (Im sure its the same in a lot of other places as well) the float plane pilots use nautical charts and most of them have a marine radio on board.

Because when they are on the water, they are counted as maritime craft and have to obey the rules for ships.

Jan

Quoting MD11Engineer (Reply 20): Even today almost all airfields have a rotating light beacon (white flashing for civilian airports, green-white for military ones).

Judging by your flag, it must be a country varience   In the USA, the rotating beacon for a civilian airport is an alternating green and white flash, for military, its a green and double-white flash.

Before Loran and Decca nav systems were out, there was a German invention called the CONSOL, working on long waves with a number of stations around the Atlantic coasts of Europe - their main user was the Kriegsmarine and the U-boote .
It was a rather ackward system as it relied on the operator listening to a succession of dots and dashes, counting them and identifying the -at least two - stations involved.
For a well-trained operator, the precision was rather good, and very useful for marine search and rescue. As far as I know, the last station, at Ploneis in Brittany was closed in the late seventies, but I was told that the antennae are still there.

Quoting SEPilot (Reply 12): oting PPVRA (Reply 11): I once read in these forums someone (or someone who knew someone) who is/was a pilot and used, just for fun, sextants on their Atlantic crossings. For quite a while before, during, and for a time after WWII long distance (over ocean) flying relied on sextants. Ernest Gann talks about it in "Fate is the Hunter."

The use of a sextant was certainly not for fun and lasted until the Inertial platforms had been validated. As a young ex-cadet with a Nav ticket, I participated in those trials, using the famed Kollsman periscopic : bubble sextant. It looks like the one pictured on the VC-10 pic above. Funny to think that all the manuals necessary for that kind of navigation - Star tables, HO 249, Logs, ephemeris....- weighing some thirty kilos, are now contained in a PDA !
It was a phenomenal learning experience as we youngsters could see the true magic of a well-experienced aircrew on free gyro / polar compass navigation.
Funny, too, that you lot forgot the inertial navigation, which killed the nav officer on board airplanes. As a matter of fact, that was the reason, we were doing those validation flights : the younger nav officers were been transformed into pilots.

Quoting Dainan (Thread starter): At airports like London City Airport, do they use a common com frequency for ships and airplanes? I only assume that it woudn't be wise for a sailship to pass the end of the runway with an Avrojet spooling up four engines for take off :p

I can't speak to LCY, but here's a chart for Boston:

http://204.108.4.16/d-tpp/1102/00058IL4R.PDF

Note the change in minimums when the tower reports tall ships in the approach area. So the tower must have some way of knowing that those ships are there. While boats and aircraft don't have the same sort of comm equipment in general, I'd imagine that the tower at BOS has a marine radio, and the ships will call the tower and let them know that they are moving through the area, and then the tower can relay that to the aircraft.

-Mir

Quoting Pihero (Reply 23): It was a rather ackward system as it relied on the operator listening to a succession of dots and dashes, counting them and identifying the -at least two - stations involved.

Sounds similar to the long obsolete four course range.

http://www.youtube.com/watch?v=p-VqtNY8vpw

Quoting Fly2HMO (Reply 25): Sounds similar to the long obsolete four course range.

Not at all, the Consol was a complete positioning nav system, whereas the "four course range" beacon system only provides a *line of positions" one needs to validate.
here is a brief description of the Consol.
One could say that it was the grand father of the LORAN, Decca nav system and the Omega/VLF used by nuclear submarines for its underwater propagation properties.

[Edited 2011-03-02 10:19:45]

Quoting MD11Engineer (Reply 21): Because when they are on the water, they are counted as maritime craft and have to obey the rules for ships.

That isn't true at all, they use them for depth and so they get an idea of underwater reefs and rocks.

Quoting Pihero (Reply 26): One could say that it was the grand father of the LORAN, Decca nav system and the Omega/VLF used by nuclear submarines for its underwater propagation properties.

Ah gotcha. I got the impression the dots and dashes would've been used in a similar fashion to a 4 course range.

I stand corrected on gps for the terminal area and approaches. Thank you.

I was trying to figure why I thought that in the first place.

I do remember the whole issue with SA and the need for accuracy better than the then available 100meters driving the need for differential gps which would eliminate the degradation caused by SA. But SA is turned off now so it is not a big of an issue that it once was.

For most part there are caveats to using gps on ships. In aircraft, ICAO has established that WGS-84 is the geodetic datum used for aeronautical data so you can use the gps position directly. There is no reassurance with nautical charts. You have to convert the gps position to a position that you can plot on the chart if the chart is not using the wgs-84 geodetic datum, an example is in japan - your position can be more than two miles off if you don't convert the gps position to the chart you are using.

The navy has lost a few ships when the crews were using gps as the sole source navigation sensor.

Quoting woodreau (Reply 29): The navy has lost a few ships when the crews were using gps as the sole source navigation sensor.

Which is odd considering even my basic Garmin handheld GPS can be set to show the coordinates of pretty much every geodetic datum out there. You'd think billion dollar warships would have the same capability.

The capability is there with the WRN-5 which is used aboard ship but was operator error. But it is not user friendly like your garmin is. The crew never thought to check the datum used on the chart. And thus never knew to have the gps receiver set to convert the gps position to a local datum position they could use on the chart. When they plotted their position they thought they were in good water when in actuality they were standing into shoal and ran hard aground doing over 15 knots. They tore the bottom out of the ship.

Quoting woodreau (Reply 29): The navy has lost a few ships when the crews were using gps as the sole source navigation sensor.

I don't know about the navy but a few small boats have come to grief due to the crew plotting waypoints and neglecting to check what lay between them, such as submerged rocks or even spits of land. There always seems to have been a small number of people who believe that as long as you tell the system where you want to go, it'll take care of "everything else".

Quoting alaska737 (Reply 27): Quoting MD11Engineer (Reply 21): Because when they are on the water, they are counted as maritime craft and have to obey the rules for ships. That isn't true at all, they use them for depth and so they get an idea of underwater reefs and rocks.

I think Jan was referring to the marine radio. When a seaplane is on the water, it does have to follow the COLREGS (Navigation rules for vessels). The charts and radio certainly help with that.

Fortunately the red and green navigation lights on the airplane work just as well at sea.

Quoting woodreau (Reply 29):

That's pretty interesting. With marine travel being far older than aviation, you'd think that some sort of "regulating body", like an "ICAO of the seas" would have standardized everything before ICAO and aviation was even a twinkle in someone's eye. Thanks for that post, you certainly learn something new here everyday, even if its not aviation.

Quoting woodreau (Reply 31): . They tore the bottom out of the ship.

Ouch. Somebody got fired after that.   

Quoting Northwest727 (Reply 34): Quoting woodreau (Reply 29): That's pretty interesting. With marine travel being far older than aviation, you'd think that some sort of "regulating body", like an "ICAO of the seas" would have standardized everything before ICAO and aviation was even a twinkle in someone's eye. Thanks for that post, you certainly learn something new here everyday, even if its not aviation.

The nautical realm definitely is a whole different ballgame.

Along with what Woodreau said about datum issues, many charts haven't been updated for decades or centuries - despite the fact that the marine environment changes all the time. In my old stomping grounds off Nantucket the shoaling rendered channels on the chart unusable due to our draft. We found that out by watching the depth sounder and turning around when we ran out of guts. Sometimes the 'lead line' and a healthy dose of skepticism are your best friends. Could you imagine towers and other obstructions popping up around an airport and not being added to the approach charts for years?!

On your worst day you deal with a 'better class of loser' in aviation. Here in the US at least it seems that any yahoo can get a boat and ruin your day...

Quoting woodreau (Reply 29): your position can be more than two miles off if you don't convert the gps position to the chart you are using.

What datum differs by two miles from WGS84?

Quoting David L (Reply 32): Quoting woodreau (Reply 29): The navy has lost a few ships when the crews were using gps as the sole source navigation sensor. I don't know about the navy but a few small boats have come to grief due to the crew plotting waypoints and neglecting to check what lay between them, such as submerged rocks or even spits of land. There always seems to have been a small number of people who believe that as long as you tell the system where you want to go, it'll take care of "everything else".

This applies to aviation as well. When GPS controlled autopilots came up in GA, there were a lot of complaints about VFR pilots just pressing the "go directly to the selected waypoint" button without checking first if there were e.g. control zones or restricted areas in the way.

Jan

INS and Omega, as well. INS being developed initially for ballistic missile subs.

An then there were several Soviet/Russian systems that paralleled the western ones. CHAYKA, Alpha and GLONASS, for example (corresponding roughly to LORAN, Omega and GPS). And several of the other satellite navigation systems.

And did someone mention direction finding on radio beacons yet?

Quoting ThirtyEcho (Reply 18): I can think of one form of marine navigation that never quite made it into aviation. The ancient Polynesians could navigate over vast distances of open ocean by "reading" wave types and currents. That is like flying from Dallas to Chicago by recognizing individual clouds

Not sure how similar the practices were, but I believe in the celestial nav days the navigator would use wave size and direction to try and determine winds.

Quoting doug_Or (Reply 40): I believe in the celestial nav days the navigator would use wave size and direction to try and determine winds.

That would be the determination of the famed PLOP ( acronym for *pressure line of position* ) in the pre-INS days, when navigation was an art and an act of faith (in oneself).