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Old 24-01-2020, 15:23   #76
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Re: GPS jamming in Flordia

Quote:
Originally Posted by Chotu View Post
It's something that happens. People on here have experienced the same. .
I've read every post, and most of the people on here who've said that they've been there said they had NOT experienced any GPS loss.
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Old 24-01-2020, 15:38   #77
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Re: GPS jamming in Flordia

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Originally Posted by Checkswrecks View Post

Bottom line is that a loss of signal can happen and be both sudden and unexpected.
Of course that is true, but Chotu is insisting
Quote:
GPS is permanently jammed near the UN in the east River and has been for decades.
At least, that's what he said on the first page of this thread. A few posts above this, he seems to have hedged, saying
Quote:
when there is an event going on
and
Quote:
Definitely a GPS deadzone very often
both of which directly contradict the first claim.

The assertion that GPS could be jammed at water level but not at 100 feet above is pretty hard to swallow.
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Old 24-01-2020, 15:49   #78
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Re: GPS jamming in Flordia

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Originally Posted by Brewgyver View Post
Of course that is true, but Chotu is insisting


At least, that's what he said on the first page of this thread. A few posts above this, he seems to have hedged, saying

and

both of which directly contradict the first claim.

The assertion that GPS could be jammed at water level but not at 100 feet above is pretty hard to swallow.

Frankly with commercial aviation flying over each and every few minutes it would have to be low level area specific.
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Old 24-01-2020, 16:43   #79
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Re: GPS jamming in Flordia

One cheap and simple countermeasure used to reject surface-located jamming/spoofing and other interfering sources is to block the receiving antenna's ability to receive signals at the horizon. The antenna is mounted in what amounts to a tin can that obscures the horizon. This is becoming a common countermeasure to reduce the vulnerability of fixed-location installations used for timing (network time protocol, cell site TDMA timing sources, etc.).

For sailboats, there are two complications: sailboats heel and roll in the seastate, so (without a gimbaled platform) the obscuration has to block more of the horizon to accomdate anticipated maximum degrees of heel. And, since some of the sky is obscured, fewer satellites can be received, making the utilization of multiple constellations much more important. Systems using GNSS for timing only need to receive one satellite - you need a minimum of four for navigation use.

The countermeasure is ineffective against airborne/spaceborne jamming/spoofing/interfering sources. Anyone wanting to jam GNSS over a wide area like a continent would have to use a satellite-based jamming source (which for a nation state, is feasible). I think of that whenever North Korea launches another "research" satellite.

There have been a lot of jokes about the US Space Force, which went live a month ago. I'm not laughing. It's needed. There are now five battlefield "domains":

1. Ground
2. Sea
3. Air
4. Space
5. Cyber

I work in the "Fifth Domain."
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Old 24-01-2020, 18:14   #80
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Re: GPS jamming in Flordia

When the Airforce does Redflag up in Alaska, it sometimes jams GPS. Our (US) battlefield systems need to be tested is GPS compromised environments. When a nav system reads 100 nm off..or does not correlate it makes one appreciate just how reliable the system is the vast majority of the time. One also appreciates conventional, maintained, aids to navigation when GPS is getting whacked!
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Old 24-01-2020, 19:17   #81
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Re: GPS jamming in Flordia

Quote:
Originally Posted by Cpt Pat View Post
One cheap and simple countermeasure used to reject surface-located jamming/spoofing and other interfering sources is to block the receiving antenna's ability to receive signals at the horizon. The antenna is mounted in what amounts to a tin can that obscures the horizon. This is becoming a common countermeasure to reduce the vulnerability of fixed-location installations used for timing (network time protocol, cell site TDMA timing sources, etc.).

For sailboats, there are two complications: sailboats heel and roll in the seastate, so (without a gimbaled platform) the obscuration has to block more of the horizon to accomdate anticipated maximum degrees of heel. And, since some of the sky is obscured, fewer satellites can be received, making the utilization of multiple constellations much more important. Systems using GNSS for timing only need to receive one satellite - you need a minimum of four for navigation use.

The countermeasure is ineffective against airborne/spaceborne jamming/spoofing/interfering sources. Anyone wanting to jam GNSS over a wide area like a continent would have to use a satellite-based jamming source (which for a nation state, is feasible). I think of that whenever North Korea launches another "research" satellite.

There have been a lot of jokes about the US Space Force, which went live a month ago. I'm not laughing. It's needed. There are now five battlefield "domains":

1. Ground
2. Sea
3. Air
4. Space
5. Cyber

I work in the "Fifth Domain."
I suspect these guys have the capability to jam GPS
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Old 24-01-2020, 20:44   #82
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Re: GPS jamming in Flordia

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Originally Posted by Zanshin View Post
Most here probably don't remember the cold war days when GPS kinda-sorta-almost worked accurately most of the time. It was called "Selective Availability" and the GPS values would be distorted in a pseudo-random way and only devices with the special decoding hardware would remove the "randomness". The US Military can and does still turn on SA in special circumstances.
Haha...
I reckon most on CF can remember when GPS wasn't even a thing
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Old 25-01-2020, 05:15   #83
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Re: GPS jamming in Flordia

Quote:
Originally Posted by Cpt Pat View Post
...There are now five battlefield "domains"...
And yet it never gets any clearer who or what we're 'battling'.

High time to look in the mirror...
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Old 25-01-2020, 08:24   #84
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Re: GPS jamming in Flordia

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Originally Posted by jimbunyard View Post
And yet it never gets any clearer who or what we're 'battling'.

High time to look in the mirror...
Ain't that the truth!!!

After 9-11 I worked the Pentagon investigation on night shifts. Normally there is a regular sound of airliners from Reagan airport, but after 9-11 there was just the sound of a lone fighter or two circling high overhead. We discussed how bin Laden got us to damage ourself.

Sorry - End of thread derailment
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Old 25-01-2020, 08:58   #85
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Re: GPS jamming in Flordia

After reading this thread yesterday, I realized that I was going to be driving my car by the UN shortly, so out of curiosity I activated the SailFreeGPS app on my cell phone and observed the readings as I approached and passed the UN on the FDR drive (for non NYers, this is a highway that passed the UN along the East River, and in fact passed just below the plaza). I was in the lane that was no more than 2 meters from the river, and noticed no change whatsoever in the ability of the app to give me new position fixes every half second or so.

I have no idea whether there was any event occurring at the UN (and when there is, security in the neighborhood can indeed get somewhat intense), but there certainly was no "jamming" taking place as of yesterday. Whether it takes place during times of high security I cannot say.


Brings to mind, however, an adventure I had a couple of decades ago, when my "yacht" at the time was a 13.5 foot (4 meter) Sunfish, and a friend convinced me that we should attempt to circumnavigate Manhattan Island by sail in a day (he did all the planning to account for the sometimes intense tidal currents). While the cruise was long and ultimately successful, as we passed by the UN we did get stopped (albeit not "boarded", given there was no room!) by a police boat, and the officers inquired as to our motives. After we assured them we had no SCUD missiles aboard, they allowed us to proceed (while shaking their heads as to how daft we were to attempt to navigate NY Harbor on such a craft.
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Old 25-01-2020, 09:09   #86
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Re: GPS jamming in Flordia

Quote:
Originally Posted by Poche View Post
I have heard that Loran might make a come back as GPS is vulnerable. Any news of that? Maybe another thread would be better for this but if anybody knows a quick link to an article.
In the US eLORAN (enhanced LORAN) was brought back as a concept in the Timing Resiliency Act of 2018:

Quote:
. National Timing Resilience and Security Act of 2018

On December 4, 2018, President Trump signed the Frank LoBiondo Coast Guard Authorization Act of 2018 (P.L. 115-282), which includes as Section 514 the National Timing Resilience and Security Act of 2018.

The act amends Title 49 of the U.S. Code to include the following language:

§ 312. Alternative timing system
(a) In General.—Subject to the availability of appropriations, the Secretary of Transportation shall provide for the establishment, sustainment, and operation of a land-based, resilient, and reliable alternative timing system—
(1) to reduce critical dependencies and provide a complement to and backup for the timing component of the Global Positioning System (referred to in this section as ‘GPS’); and
(2) to ensure the availability of uncorrupted and non-degraded timing signals for military and civilian users in the event that GPS timing signals are corrupted, degraded, unreliable, or otherwise unavailable.

The act goes on to provide specific direction regarding: establishment of requirements; implementation plan; LORAN facilities; and agreement authority
Whether or not it happens will depend on appropriations.

On a second subject, this paper on GPS spoofing around Putin (amongst other places) shows that the jammed signal itself can be used to detect the location of the thing/person/structure being protected by the spoofing/jamming.
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Old 25-01-2020, 13:55   #87
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Re: GPS jamming in Flordia

Quote:
Originally Posted by Chotu View Post
Until you transit the area several times when there is an event going on, I'm not going to entertain your nonsense.

You speak from the armchair, having never once been through the area by boat.

Don't get your panties in such a bunch over things you are guessing about from afar.

It's been going on for decades in which time I've had 3 boats in that area. "My installation". Lol. Ok.


It's something that happens. People on here have experienced the same. All the babbling in the world isn't going to change that. You aren't from the area. You don't know what you're talking about flying above. It's local and in the East River. Definitely a GPS deadzone very often in the security area near the UN.

Just because you don't like it and want to go on an internet war about doesn't make it stop happening.

And you're telling me to furnish proof? You need to get a job. Or maybe I need your job and to not build my new boat because I'm not sure where you're finding the time for all of this nonsense.

Chotu, out.
It is always startling when one encounters this kind of post - CF is overwhelmingly populated with people that are generous with their time, kind, and will do a "hey I didn't know that" when someone corrects something or will really dig in and provide details and supplemental info to flesh out a claim or question.
Then there are the few who make outlandish statements with sufficiently little specificity that it is hard for any of us to know what to make of it and when questioned, dodge the substantive question and berate and belittle those who dare to question.
Thanks to redneckrob for your thoughtful and useful note.
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Old 25-01-2020, 17:45   #88
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Re: GPS jamming in Flordia

Quote:
Originally Posted by lestersails View Post
It is always startling when one encounters this kind of post - CF is overwhelmingly populated with people that are generous with their time, kind, and will do a "hey I didn't know that" when someone corrects something or will really dig in and provide details and supplemental info to flesh out a claim or question.
Then there are the few who make outlandish statements with sufficiently little specificity that it is hard for any of us to know what to make of it and when questioned, dodge the substantive question and berate and belittle those who dare to question.
Thanks to redneckrob for your thoughtful and useful note.
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Old 26-01-2020, 02:54   #89
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Re: GPS jamming in Flordia

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Originally Posted by jimbunyard View Post
And yet it never gets any clearer who or what we're 'battling'.

High time to look in the mirror...
We've become too dependent on fragile technologies that are setting us up for a fall.

Fortunately, as long as there's wind, sailboats still function.
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Old 26-01-2020, 03:30   #90
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Re: GPS jamming in Flordia

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Originally Posted by Cpt Pat View Post
We've become too dependent on fragile technologies that are setting us up for a fall.

Fortunately, as long as there's wind, sailboats still function.
Kind of like when they added computers and fuel injection to cars and everyone bemoaned that they would never last.

This was when getting 100k miles out of a car was doing good...and that required regular tune ups and usually at least a couple significant engine repairs.

Now it's common to get 200-250k miles out of a car with no major work beyond filter and fluid changes (yeah, they list a few more things out in the manual but most people never bother)
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