Is your GPS up to date?

[Bayless]

From these descriptions, it sounds like the SINS system is just automated dead reckoning.

 

[waltesefalcon]

"the downside is you have no clue as to where YOU are on that paper map."

Not if you know how to read a map. I might not be able to get it down to within a few yards or feet but I can reckon my position to within a mile or so when using a map. You can also calculate how long a trip will take and what your average speed will be using one. There really isn't any overland navigation you can't do with a paper map.

 

[waltesefalcon]

From these descriptions, it sounds like the SINS system is just automated dead reckoning.

It does sound like that.

 

[PAUL161]

My wife always asked me, why do you read a map all folded up and upside down or sideways? Got used to that reading sectional charts reading them in the direction I'm flying. She still thinks it's weird! :highly_amused:

 

[TR3driver]

From these descriptions, it sounds like the SINS system is just automated dead reckoning.

From my point of view, SINS is actually less than dead reckoning. DR can include inputs from things like Doppler Sonar, while SINS only uses inertial sensors.

A big advantage of SINS (from the military point of view) is that it does not emit any external signals (which might reveal your location to an enemy), or rely on inputs from external signals (which might be corrupted by an enemy). Biggest disadvantage (as mentioned) is that it's accuracy degrades substantially over time.

One of the systems we used to sell would allow submarines to almost surface ("periscope depth") and extend an antenna above the surface just long enough to get a satellite fix, to recalibrate their inertial system.

That was before GPS, though. Sat fixes were only available at very certain times, and it took many minutes to collect enough information to calculate a fix. Many minutes more for the calculations (with the computers available then) and after all that, results weren't good to better than 100 feet or so, for a time many minutes in the past.

Of course, the vessel would continue to move during all that, so you had to store where you thought you were, and compare that to where the satellite fix thought you were, then subtract that from where you thought you were now, to arrive at where you think you might be now.

Throw in a couple of radio nav aids and it really got fun! Loran, Omega, Syledis, etc all had errors that were worse in some directions than in others (as did the Transit sat fixes as well). So our main product was the computer system to try to arrive at the best solution given all those disparate inputs.

Good times, lots of fun problems to solve. I often worked late into the night, because it was more fun than watching television or going to the beach.

 

[Deleted member 8987]

Boy, this thread went down the tube...

And, as for hemispherical influence on drain rotation, while it makes for a neat story:

https://mentalfloss.com/article/303...-dont-flush-backwards-because-coriolis-effect

and

https://www.snopes.com/fact-check/coriolis-effect/

and if you believe snopes without outside impartial collaboration, you're on thin ice with the political ban here.

Seen both hemispheres, had it shown me in gyros, so who knows.

I suppose there are many places in at least North America with an inherent left spin.

 

[Deleted member 8987]

From these descriptions, it sounds like the SINS system is just automated dead reckoning.

I can see how yo might think that. DRAI (Dead Reckoning Analyzer Indicator) used EM Log speed and compass input to drag a bug under the class and chart.
Dead Reckoning took more active input, radar fixes, LORAN fixes, celestial fixes, to up date position. You guessed on speed and heading between fixes (no set, drift, current action).

SINS, at least the ones I worked on, before MINI-SINS, used a binnacle (gimballed platform) with gyros to keep heading, and all axis level...because....PIPAs (pulse integrated pendulous accelerometers) measured N-S and E-W speed.....think yo-yo wired up. Hand the yo-yo, sake a step to start walking. Yo-yo moves back, the comes forward. If a potentiometer was wired across the bottom of the arc of the yo-yo, signal sen to a computer would read signal when you moved, and signal when your acceleration stopped, recording your actual speed. So, if you are walking 045 degrees, you have a component of N-W speed saved in the computer, and E-W speed in the computer, which adds and subtracts from lat and long to give you printouts in line on the modified IBM Selectric for use by the quartergasket in updating his DRAI while greater that 400 feet and faster than 20 knots.
We had a DOC, or Data Output Console, that took the N-S and -W data, and the heading, and via servos generated an actual speed in the direction of travel.

Somewhere around here I think I still have all my books on the SINS system.

BTW, the first four Trident boats had (maybe still do) twin SINS with binnacle.

 

[Mickey Richaud]

and if you believe snopes without outside impartial collaboration, you're on thin ice with the political ban here.

Seen both hemispheres, had it shown me in gyros, so who knows.

I suppose there are many places in at least North America with an inherent left spin.

OK, I'll play:

https://www.washingtonpost.com/news...-swirls/?noredirect=on&utm_term=.cce98fb9628b

https://www.loc.gov/rr/scitech/mysteries/coriolis.html

https://science.howstuffworks.com/science-vs-myth/everyday-myths/rotation-earth-toilet-baseball2.htm

https://www.scientificamerican.com/article/can-somebody-finally-sett/

Plenty more where those came from. And there are others that "prove" othewise".

By the way, I've been to Ecuador - five times. Never seen reverse rotation in a toilet....

...But then, I didn't spend a LOT of time in the loo... :friendly_wink:

 

[Boink]

I didn't see the effect down-under, but I'm told that the effect is only seen on VERY large scales (such as weather and spinning storms). The single most significatn determinant of spin in a drain is the starting direction (caused by small things at that location). Even a simple sink test in Australia didn't show the effect beyond randomness.

 

[John Turney]

um.....not quite. Depends on the SINS, I suppose.
...

It was a joke.

 

[Deleted member 8987]

It was a joke.

oh, okay. After all those years, SINS wasn't a joke.

As far as Coliolis Effect, larger scales yes, most definitely, terlits, yeas, unless as I said initially the bowl is configured with the flush squirter at the bottom aimed to start it differently.

When the military takes it serious enough to compensate in the computer programs of the SINS systems for nuclear submarine submerged navigation, I tend to give that more credence than Snopes or any, and I mean ANY, news platform that simply parrots the political bent (whatever it is) of Snopes.

You ever READ that garbage?

"Partially True" basically means it is true, but they are going to add THEIR spin to make you question whatever it is.

I WATCHED the effect on SINS with gyro changes once we crossed that line. Not big at first, but moreso the further north or south of the line you got.

Isn't Scientific American the spokesplace for Global Warming?

 

[Deleted member 8987]

Oh...wait. Sorry, I just remembered what forum I was on. This is the place when your taillights quit it's the coil, right? It's ALWAYS the coil.

I'll shut up on this now.


Back to your regularly scheduled.........

 

[John Turney]

Moving further afield, when I first saw this thread, it reminded me of "Does your chewing gum lose its flavor on the bedpost overnight?"

 

[Deleted member 8987]

if your momma say don't chew it but you swallow it in spite?

https://www.youtube.com/watch?v=x6bFTVi0hHs

 

[DavidApp]

The article on the net that got me thinking about GPS updates reminded me that it has been a while since I did a map update.

My old (10+ year old) Garmin updated with no problem but when I connected my other Garmin (a NUVI 2757LM) much newer the GPS complained that I was not using the correct cord to charge it but it did show that it was connected to the a computer and it was charging. My windows 10 laptop will not detect it now. It did detect it in the past but windows must have done something in one of their updates so it will not connect? My old desktop Windows XP detects it fine but does not have enough disk space to download the maps. It is saying it needs 9 meg. of space. Garmin will not work with Linux Mint.

Sometimes I think I need to go back to AAA triptiks.

David

 

[TR3driver]

Maybe this is the problem?
https://support.microsoft.com/en-us...don-t-work-with-windows-10-anniversary-update

 

[DavidApp]

Thank you Randall

I will check that out.

David

 

[LarryK]

While carrying mail in Columbia, IL, I noticed the gps would always pinpoint a dead end street as the center of town. Once a lady asked me how to get from the street we were on to Main St. I pointed out she would have to go up two more streets and go left. She countered me with, "her TomTom says she could go across another street where she came from" I then told to go that way and I'll call a tow truck. There was a 10' ditch at the end of the street and you could see Main St.

 

[JPSmit]

While carrying mail in Columbia, IL, I noticed the gps would always pinpoint a dead end street as the center of town. Once a lady asked me how to get from the street we were on to Main St. I pointed out she would have to go up two more streets and go left. She countered me with, "her TomTom says she could go across another street where she came from" I then told to go that way and I'll call a tow truck. There was a 10' ditch at the end of the street and you could see Main St.

I had a similar version last year. GPS took me to a residential cul de sac. I could see the main street - connected by a walking path. The good news was I was driving SWMBO's mini - fit the path perfectly. :grin:

 

[LarryK]

Evrytime I see a path I act like I'm heading for it, the wife always yells, "NO!"