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24-01-2021, 15:45
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#16
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Registered User
Join Date: Jun 2014
Location: Chesapeake
Boat: Catalina 22 Sport
Posts: 1,035
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Re: Better get serious..
Quote:
Originally Posted by Kamen
No, you are not. Modern smartphones contain a GPS chip. There are many phone apps that are specifically designed for offline navigation: Gaia GPS, OnX, even Google Maps. However, it is true that a phone can fuse GPS with cell tower and wifi signals to improve accuracy and reduce power consumption.
BTW, smartphones also contain other cool sensors that are useful for navigation, such as accelerometer, a gyroscope, a magnetometer.
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Thanks Kamen. So, then I am puzzled why when I am out hiking far from civilization my phone map positioning does not work...
I am pretty sure I have been asea and the same thing happens.
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24-01-2021, 15:55
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#17
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Registered User
Join Date: Jun 2019
Location: Rochester, NY
Boat: Chris Craft 381 Catalina
Posts: 4,605
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Re: Better get serious..
Quote:
Originally Posted by lestersails
Thanks Kamen. So, then I am puzzled why when I am out hiking far from civilization my phone map positioning does not work...
I am pretty sure I have been asea and the same thing happens.
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Check the settings on your phone to make sure it's configured to use the actual GPS chip. It might be turned off to save power. It also depends on the app you're using. Some rely on having a data connection, others don't.
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24-01-2021, 16:24
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#18
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Registered User
Join Date: Sep 2011
Location: Good question
Boat: Rafiki 37
Posts: 13,409
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Re: Better get serious..
Quote:
Originally Posted by psk125
Having "backup systems" like Glonass or Galileo to replace a blocked US GPS system is not a solution. If the US system - the one that all our defense armament depends upon - is knocked out, Washington will be knocking out the others in short order, (like in within two minutes?) to prevent attacks. Someone above suggested that they could use a cellphone to back up their GPS. Right. It's like a power outage. Changing the lightbulbs or running an extension cord to a different outlet is not going to make any difference. Nothing that plugs in is going to work. You will need flashlights and candles: compass, chronometer, sextant and tables - to determine where you are if the systems are shut down.
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Of course, in a time of all out war, all bets are off, but even in those cases, why would the USA knock out the European or other allied systems if theirs go down? I bet (hope) they rely on allied systems for redundancy.
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24-01-2021, 16:24
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#19
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Senior Cruiser

Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,800
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Re: Better get serious..
Quote:
Originally Posted by lestersails
Thanks Kamen. So, then I am puzzled why when I am out hiking far from civilization my phone map positioning does not work...
I am pretty sure I have been asea and the same thing happens.
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Bet you've got an iPhone. Many of them do need a cell signal - unlike almost every Android device out there.
(don't get me started on Apple devices and their users  )
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24-01-2021, 16:28
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#20
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Registered User
Join Date: Sep 2011
Location: Good question
Boat: Rafiki 37
Posts: 13,409
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Re: Better get serious..
Quote:
Originally Posted by StuM
Bet you've got an iPhone. Many of them do need a cell signal - unlike almost every Android device out there.
(don't get me started on Apple devices and their users  )
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Not true for any iphone or ipad I've owned going back to an iphone 3, or my spouse has owned. It has a stand alone GPS receiver. It uses cell towers to refine your location, but without it uses the GPS signal.
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24-01-2021, 16:33
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#21
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Registered User
Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 20,412
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Re: Better get serious..
Ah iPhone crowd and their insisting on paying 999.99 USD a year for a device without gps onboard.
Why can't people get a 99.99 USD Android device instead? Too cheap? Buy 10! ;-)
b.
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24-01-2021, 17:38
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#22
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Registered User
Join Date: May 2018
Location: Nevada, USA
Boat: boatless currently
Posts: 100
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Re: Better get serious..
Quote:
Originally Posted by lestersails
Thanks Kamen. So, then I am puzzled why when I am out hiking far from civilization my phone map positioning does not work...
I am pretty sure I have been asea and the same thing happens.
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What phone do you have?
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24-01-2021, 17:45
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#23
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Registered User
Join Date: Sep 2010
Location: Land of Disenchantment
Boat: Bristol 47.7
Posts: 5,544
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Re: Better get serious..
Quote:
Originally Posted by Mike OReilly
Not true for any iphone or ipad I've owned going back to an iphone 3, or my spouse has owned. It has a stand alone GPS receiver. It uses cell towers to refine your location, but without it uses the GPS signal.
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I believe this is only available in Apple devices which have both wifi and cellular data capability. At least the last time I looked into it (couple of years).
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24-01-2021, 20:00
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#24
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Registered User
Join Date: Sep 2011
Location: Good question
Boat: Rafiki 37
Posts: 13,409
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Re: Better get serious..
Quote:
Originally Posted by Exile
I believe this is only available in Apple devices which have both wifi and cellular data capability. At least the last time I looked into it (couple of years).
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Not wifi, cellular data. All have wifi. But you can buy non-cellular and therefore non-GPS versions of the ipad. Not the iphone. All cellular data-enabled iThings have a GPS receiver.
All have wifi receivers.
I'm platform agnostic. I like iThings because of my history with Apple, and their reliability, but it's just a tool.
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25-01-2021, 07:31
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#25
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Registered User
Join Date: Jun 2014
Location: Chesapeake
Boat: Catalina 22 Sport
Posts: 1,035
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Re: Better get serious..
Quote:
Originally Posted by Kamen
What phone do you have?
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Hi Kamen
11 Pro. According to Apple's online specs it says:
Location
Built-in GPS/GNSS
Digital compass
Wi‑Fi
Cellular
iBeacon microlocation
So, that could not be clearer. What I need to do is to get back out in the boonies and try again, with and without my BadElf.
Les
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25-01-2021, 19:10
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#26
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Registered User
Join Date: Mar 2011
Location: Southport CT
Boat: Sabre 402
Posts: 2,352
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Re: Better get serious..
Quote:
Originally Posted by Mike OReilly
Of course, in a time of all out war, all bets are off, but even in those cases, why would the USA knock out the European or other allied systems if theirs go down? I bet (hope) they rely on allied systems for redundancy.
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Because the Russians, N Koreans, Chinese or Iranians would use them as backup to direct their missiles at us. (Or our allies!) If ours goes down - everybody's goes down. Hopefully the US military has a protected, encrypted version that would not go down. GPS started with rather few satellites in place. There may be enough of them up there now that taking them all out would be difficult to do. Removing a bunch of satellites might degrade the results, but not enough to make it stop working entirely.
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25-01-2021, 19:53
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#27
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Registered User
Join Date: Apr 2008
Location: U.S., Northeast
Boat: Contessa 32
Posts: 1,594
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Re: Better get serious..
Quote:
Originally Posted by lestersails
Hi Kamen
11 Pro. According to Apple's online specs it says:
Location
Built-in GPS/GNSS
Digital compass
Wi‑Fi
Cellular
iBeacon microlocation
So, that could not be clearer. What I need to do is to get back out in the boonies and try again, with and without my BadElf.
Les
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iPhones use Assisted GPS (AGPS) technology. AGPS receiver uses cell phone tower data to more quickly initialize location and as a backup in areas of poor satellite reception. If cell tower signal is not available, cold start initialization can take several minutes, but the receiver should eventually acquire satellites. However, when you're hiking under a leafy forest canopy, the water in the leaves will attenuate the signal and degrade reception.
A gps receiver specifically designed for navigation may very well have a better antenna than a cell phone.
__________________
... He knows the chart is not the sea.
-- Philip Booth, Chart 1203
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25-01-2021, 20:19
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#28
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Moderator Emeritus
Join Date: Aug 2005
Location: Carlsbad, CA
Boat: 1976 Sabre 28-2
Posts: 7,505
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Re: Better get serious..
A few years ago you had to get the cellular equipped iPad to get a GPS chip built in, don't know if that's still the case. No idea on the iPhone.
Had my small/old Garmin GPS put me 50 miles closer to Monterey than I was. We we didn't see land after a few hours got out my hand held back up which gave me Lat/Long and plotted position 50 miles farther at sea. Latitude was right but longitude nearly a minute off on the offending GPS. Ducked into Monterey to make other repairs and bought a new 5" Garmin GPS that got me to my destination. The erring GPS still insisted I was a few miles off shore even though I was in the marina so packed it away. Tried it again when I got to Oceanside and it was working correctly No idea why it suddenly got cockeyed.
When we sailed to French Polynesia in mid '70s had a Sony Short Wave receiver for time and weather on WWVH, a Timex quartz watch, a neon tube depth sounder that you couldn't read if it was sunny, a Walker Log and the sextant.
__________________
Peter O.
'Ae'a, Pearson 35
'Ms American Pie', Sabre 28 Mark II
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25-01-2021, 21:06
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#29
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Registered User
Join Date: Aug 2020
Posts: 56
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Re: Better get serious..
Eh. I think there should hesitation towards total reliance on GNSS but even self driving cars still need digital eyes on the road to see where they are.
In the event of a world war, USA and Russia do reserve the right to shutdown GPS and GLONASS but I believe Galileo, run by the EU, would still prevail.
For those curious just about anything from the early 2000's can do both GPS and GLONASS and later 201's should be able to do all 6 major systems GPS, GLONASS, BeiDou, Galileo, NavIC and QZSS.
The writer is probably a bit paranoid. You can't realistic block all these systems actively. They operate on different frequencies and would require HUGE amounts of RF power to block plus multiple broadcast sites. You could maybe blow up all 100+ satellites but then your pissing off alot of countries.
Also Fun Fact, John Deere has thier own Satellite-based augmentation system called StarFire navigation system. With this propriety correction data they can get 2.5 cm accuracy on thier self driving tractors. Imagine. A tractor company with thier own satellite network solely for the purpose of harvesting grain better.
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25-01-2021, 21:27
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#30
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Registered User
Join Date: Nov 2015
Location: Somewhere in the Pacific Ocean
Boat: Catalina Morgan 45
Posts: 596
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Re: Better get serious..
Quote:
Time was when nobody knew, or even cared, exactly what time it was. The movement of the sun, phases of the moon and changing seasons were sufficient indicators.
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That's pretty much how I live my life today.
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