The Future of GPS

[requiem]

Originally Posted by Norsailor

There is probably a few things I don't know about GPS technology, but pls explain how you can determine the compass heading from a GPS signal. Especially when the boat is not moving.

Here you go: https://www.powerandmotoryacht.com/e.../gps-compasses

Excerpt:

A typical GPS compass is a flat-topped, elongated dome, a few inches wide and a couple of feet long, mounted parallel to the centerline of the boat. Inside are two GPS patch antennas about a foot apart and linked to a receiver and processor in the center. If it is receiving signals from a satellite directly abeam, the radio waves that carry those signals arrive at the two antennas perfectly in step with each other (“in phase”). But suppose the satellite moves or the boat turns so that the satellite is a few degrees aft of directly abeam. Now the forward antenna is slightly farther from the satellite than the aft one, so instead of the received signals being perfectly in phase, they gradually slip farther and farther out of step.

[goboatingnow]

Originally Posted by Elleroo

My son works in radar, and was on board a naval ship doing daq. Said he was in the ops room, and was wondering what the box in the corner, turned off, was. Loran was the answer that came back, and apparently they test it monthly....


GPS is there for military use, and can be turned off in a blink.


I'll stay with my sextant and Walker log, and hand bearing compass and old B&G rdf on aero beacons.

Gps yes but there are 4 other GNSS systems up there

If all of them go off the least of your worries will be worrying about your position largely because the earth will largely be made up of fused glass !!!!

Sheesh

[goboatingnow]

Originally Posted by Norsailor

Heading is where your bow i s pointing. Where the boat is going is, as we all know, a different matter, mostly named TMG or Track Made Good. What the plotter software does, is making a history of your recent positions, which

equals the TMG.

There is probably a few things I don't know about GPS technology, but pls explain how you can determine the compass heading from a GPS signal. Especially when the boat is not moving.

Heading is the direction the direction the boat is pointing in. Real time kinematic versions using dual gps units can resolve heading better then any compass.

[goboatingnow]

Originally Posted by StuM

". The Coast Guard terminated the transmission of all U.S. Loran-C signals in February 2010 and began dismantling stations."

However, their is an alternative coming:
https://www.gpsworld.com/innovation-enhanced-loran/


https://www.xyht.com/gnsslocation-te...turn-of-loran/

Enhanced loran isn’t being rolled out , it’s dead. The U.K. led with a trial and then discontinued the service.

[Jim Cate]

Originally Posted by double u

I am tempted to say "...the good old days...", but maybe I only remember the excitement of "having it gotten right" & have forgotten the soul-searching, triple checking & standing on the foredeck & listening (just in case)

Yes, the sense of accomplishment we had when making a successful landfall under celestial is missing these days... but IMO it's a good tradeoff . I shall never forget the sense of doom I had when, on a passage from Hawaii to SF we encountered 11 straight days of overcast and our DR position was only about 60 miles from the coast.

Neptune smiled upon us that time by clearing the skies just at t he right time for evening stars, giving us a good fix and a huge sense of relief.

I enjoy and appreciate GPS navigation, but I kinda miss the satisfaction of doing it the old way!

Jim

[ArmyDaveNY]

Originally Posted by Jim Cate

Yes, the sense of accomplishment we had when making a successful landfall under celestial is missing these days... but IMO it's a good tradeoff . I shall never forget the sense of doom I had when, on a passage from Hawaii to SF we encountered 11 straight days of overcast and our DR position was only about 60 miles from the coast.

Neptune smiled upon us that time by clearing the skies just at t he right time for evening stars, giving us a good fix and a huge sense of relief.

I enjoy and appreciate GPS navigation, but I kinda miss the satisfaction of doing it the old way!

Jim

I agree, that's why I use both. I use the GPS to confirm or point out errors in what I think I know based upon my plotting.

[ArmyDaveNY]

Speaking of the future of GPS and other SatNav systems, here is a news article about a recent anti-satellite test, and a link that discusses a theory that has some concerned about the results.

It should be noted that although the Russians were the latest to do this, others such as communist China, the U.S. and India have done similar tests. The second link discusses the Kessler Effect. This postulates that a debris field of sufficient quantity could lead to increasing destruction of additional satellites, resulting in ever increasing debris fields. This would, in theory, render certain orbits useless to satellites.

The satellite that was destroyed was in a low Earth orbit whereas most SatNav systems are somewhere around 12,000 Statute Miles or 20,000 Km depending upon the system. This isn't likely an issue for the time being although it wouldn't take much, man made or natural, to affect the various systems.

https://www.ndtv.com/world-news/russ...w-nasa-2612431

https://en.wikipedia.org/wiki/Kessler_syndrome

[goboatingnow]

“ communist China” is there another China somewhere else

[carstenb]

Originally Posted by Jim Cate

Yes, the sense of accomplishment we had when making a successful landfall under celestial is missing these days... but IMO it's a good tradeoff . I shall never forget the sense of doom I had when, on a passage from Hawaii to SF we encountered 11 straight days of overcast and our DR position was only about 60 miles from the coast.

Neptune smiled upon us that time by clearing the skies just at t he right time for evening stars, giving us a good fix and a huge sense of relief.

I enjoy and appreciate GPS navigation, but I kinda miss the satisfaction of doing it the old way!

Jim

We still do celestial for fun. Great when you find out you did it right and are only 20 or so nm off when compared to the GPS

[carstenb]

Originally Posted by goboatingnow

“ communist China” is there another China somewhere else

aka Taiwan