Navigation Before The GPS

[cheesegrater]

I was just wondering, how did aircraft navigate across an ocean before the days of the GPS? For example flying across the Atlantic or Pacific. There are no VORs or ADFs on the water.

[Woodlouse2002]

I was just wondering, how did aircraft navigate across an ocean before the days of the GPS? For example flying across the Atlantic or Pacific. There are no VORs or ADFs on the water.

Compass courses, Sextant sights and a chronometer. The same way infact that ships used before GPS and radio navigation.

[Woodlouse2002]

Mustn't forget good old dead reckoning either.

[Nexus]

I was just wondering, how did aircraft navigate across an ocean before the days of the GPS? For example flying across the Atlantic or Pacific. There are no VORs or ADFs on the water.

There were several options to choose from.
You had the Loran-C and OMEGA/VLF systems, both which used ground stations with ultra long range. And these were pretty reliable  :)
But the dominant one was, and still is, the Inertial Navigation system. The INS and the derative IRS is installed in pretty much EVERY airliner, from Airbus A330 to the Boeing 747 etc. And it is fully capable of navigating the aircraft for you if you lose GPS.

I suggest you read my answer in this thread about the INS/IRS, if you want to know more about the subject  :)
http://www.simviation.com/cgi-bin/yabb/ ... 26;start=1

[beaky]

When Lindbergh did it, he made  small course changes at set time intervals, using an earth-induction compass (sort of a radio receiver that picks up the Earth's magnetic field) to set his heading, following a carefully-planned Great Circle route across the ocean. It worked out pretty well, even though he could only guess as to how much the wind would really drift him- not too many reliable wind forceasts available those days, and he had no radio to get weather reports with... too heavy.
He used a wet compass (regular old iron-bar compass that always points more or less towards the North or South Pole)to check against the earth-induction compass, but it had to be placed in an area where he needed a miror to see it. The day it was installed, they had no mirror, but a young lady in the crowd gathered outside the hangar at Curiss Field gave them the mirror from her compact, according to Lindbergh's own account. It was just the right size, and not too heavy (LOL).
He could have used a radio to get bearings from ships at sea, but decided the marine-band units available at the time were too heavy.
So other than the fancy-for-its-day induction compass, he did it by sheer deduced reckoning: no landmarks to see, so it was all about careful planning, accurate timekeeping, precision maneuvers, and lots of luck with the wind...

[C]

What's GPS?

Dirty word, almost as bad as crevice...

[Woodlouse2002]

Pity airliners arn't made with Astrodomes any more. They usually complemented the lines quite nicely.

[beaky]

What's GPS?

Dirty word, almost as bad as crevice...

I think it stands for "Glib Pilot Syndrome"... yeah, that's it.

[Hester]

"Great Pilot Simulator"?  ;)

[cheesegrater]

There were several options to choose from.
You had the Loran-C and OMEGA/VLF systems, both which used ground stations with ultra long range. And these were pretty reliable  :)
But the dominant one was, and still is, the Inertial Navigation system. The INS and the derative IRS is installed in pretty much EVERY airliner, from Airbus A330 to the Boeing 747 etc. And it is fully capable of navigating the aircraft for you if you lose GPS.

I suggest you read my answer in this thread about the INS/IRS, if you want to know more about the subject  :)
http://www.simviation.com/cgi-bin/yabb/ ... 26;start=1

Curious. The freeware INS gauge looks just like a GPS gauge found in many panels. In a real airliner (for example 747-200 or Tristar) is this a GPS or INS?

[Nexus]

Not really sure what you mean by that. Are you talking about the CIVA INS gauge by simufly?

Although some 747-200's may be GPS retrofitted, but I can assure you that both the 742 and the L1011 TriStar used INS (Probably a Delco Carousel

[cheesegrater]

Not really sure what you mean by that. Are you talking about the CIVA INS gauge by simufly?

Although some 747-200's may be GPS retrofitted, but I can assure you that both the 742 and the L1011 TriStar used INS (Probably a Delco Carousel  or a Litton unit)

Take a look at this picture of a 747-200 flightdeck. Just above the throttle levers is one of the INS control display units. In newer aircrafts that spot is now occupied by the FMC, and the inertial nav display is usually located on the overhead panel instead  :)
http://www.airliners.net/open.file/586732/L/

Yes, that is the gauge I was thinking of. Thanks for the responses.

[beaky]

"Great Pilot Simulator"?  ;)

Naahhh... a Great Pilot wouldn't need no stinkin' satellites to get a nav fix...

[beaky]

There were several options to choose from.
You had the Loran-C and OMEGA/VLF systems, both which used ground stations with ultra long range. And these were pretty reliable  :)
But the dominant one was, and still is, the Inertial Navigation system. The INS and the derative IRS is installed in pretty much EVERY airliner, from Airbus A330 to the Boeing 747 etc. And it is fully capable of navigating the aircraft for you if you lose GPS.

I suggest you read my answer in this thread about the INS/IRS, if you want to know more about the subject  :)
http://www.simviation.com/cgi-bin/yabb/ ... 26;start=1

Obviously  I was looking too far back: INS was and is a very useful tool, and predates GPS by many years.
And good ol' Loran: surprisingly accurate.

[Nexus]

[quote]


Obviously