GPS oddity

[SteveW]

It sounds like he might have been confusing GPS satellites and spy satellites.

[SteveW]

Maybe some sort of jammer to prevent GPS guided drone attack?

[Paul]

No, this guy. It's a popular meme.

This is some kind of interview with the bad hair day guy.

Paul

[Paul]

This is the basic plan. More than one GPS system exists of course. There might be a few receivers, that can receive from more than one system (can be switched between systems).

"The satellites in the GPS constellation are arranged into six equally-spaced orbital planes surrounding the Earth. Each plane contains four "slots" occupied by baseline satellites. This 24-slot arrangement ensures users can view at least four satellites from virtually any point on the planet. "

Satellites have a "dither" setting, which affects consumer receivers. The military receivers are supposed to work around that feature. This affects pointing accuracy for precision munitions. You would not want a consumer grade device to give military accuracy.

"As of July 3, 2023, there were a total of 31 operational satellites in the GPS constellation, not including the decommissioned, on-orbit spares."

I think from inside the house, and pointing the GPS antenna upwards on the window sill, I can receive "green" signal levels on two of seven birds. The fact that seven birds can be detected by the receiver (a 66 channel device), does not mean those would be useful if I moved the antenna outdoors. It just means there is enough signal for an ident.

*******

The Glonass system has some similarities.

As of 24 December 2023, the GLONASS constellation status is: 26 SC

*******

The Chinese have one.

There is still a need, as of this date, for a backup system. This is not good enough for war usage. Various things could happen to all the constellations.

Paul

[Colin Bignell]

As GPS is a military system, developed in the 1960s to help fight the expected nuclear war, I wouldn't rule out some design overlap.

[The Natural Philosopher]

It's amazing how much sheer ignorance there is out there...

[John Rumm]

Unlikely to be the cause of the OPs problem, however the Russians have apparently stuck GPS "interfering" kit in Kaliningrad recently that is supposed to be reducing GPS accuracy in adjacent bits of eastern Europe

- thought to be part of their hybrid warfare program. Piss of enough Latvian and polish Amazon delivery drivers to cause upset and unrest as well as financial hard in "unfriendly"[1] countries.

[1] i.e. most countries a this point!

[Paul]

"The MIRVs arrive in space attached to a “bus”, a very smart robot rocket.

The bus has an Inertial Measurement Unit and a Stellar Navigation Platform. These allow the bus to find its position, attitude and velocity with extreme accuracy. It can then fire bursts of rocket thrust to refine its position to a precise reentry path, a path that will hit a target within 50 yards without any further steering.

The bus was originally intended to refine the reentry trajectory of one big warhead, but then folks realized the bus had time (and rocket power) enough to adjust itself to over a dozen precise reentry paths, one after another. "

If it's not a MIRV, it's a cruise missile with terrain matching and video camera. You can fly a cruise missile along a series of valleys and it will steer using the terrain (a programmed path picked in advance).

Perhaps someone has the intention of affecting smart weapons dropped from jets at the moment. The word GPS occurs quite a few times in this article (without reading the article).

What would be the most effective way to jam GPS ? Jamming from space ?

Paul

[Paul]

I don't think they're really equipped for mobility.

Jetting around a lot wastes fuel.

Since you're on Linux, you can connect a serial or USB GPS to your Linux machine, and it will actually draw a picture of the current constellation in space. It will also print the signal level next to each one. Green dots are useful, yellow and red are less useful. Red means the ident is there, but it is unlikely to be used as part of the constellation of reception.

GPS signal level also varies with time of year. (I've had the GPS, without moving the antenna, drop out on all birds and indicate loss of sync.)

The satellite has a mass of 1,630 kg (3,590 lb) and a design life of 12 years.

"The GPS 3 SV01 spacecraft is set to reach a circular orbit at the GPS fleet’s altitude around 10 days after launch, Whitney said. Seven firings by the satellite’s liquid-fueled main engine are planned to circularize the craft’s orbit at an altitude of 12,550 miles, followed by deployments of the satellite’s solar arrays and antennas."

It would be less desirable to be doing a lot of accelerating, if the arrays happen to unfold and stick out quite a bit.

The fine control would be done with thrusters, although nothing in the pictures I can find, looks like thrusters.

The main engine might also be tasked with the de-orbit or parking burn, 12 years from now.

Since one of the GPS birds well-outlived its projected life, my guess is they're frugal with the resources.

A KH-11 might well jet around.

"The KH-11 SSB mass application is about 3,289 lbs dry while its fueled mass is about 10,568 lbs"

"The whole spacecraft dry mass is about 13,289 kilograms and the fueled mass is estimated between 24,500-25,800-27,500 lbs at orbital insertion"

Paul

[Smolley]

Sounds like that was borrowed from the TSR2 all terrain radar and moving map display.

[The Natural Philosopher]

Nope. Jamming devices are cheap and can be got on Ebay. Just broadcast noise on GPS frequencies.

Spoofing, to tell you you are somewhere else, is harder

[charles]

It affects the local earth plane

[Pancho]

My GPS comes with Beidou and Glosnass in addition to GPS. Supposed to improve reliability, dunno if it does.

Trees can cause a problem, which might be better or worse due to the current sattelite position. But 40 miles should be enough time for the positons to change as they orbit once ever 12 hours.

So use Google Maps on you phone, if you do that already buy a new phone.

[Rod Speed]

charles [e-mail]> wrote

That isnt relevant with TV signals.

[Jeff Gaines]

GPS are satellite signals aren't they?

[Andy Burns]

The receiver in my pocket doesn't have to switch between systems, it makes concurrent use of American, Russian, Chinese and European satellites.

[mm0fmf]

Most 2018 vintage phone chipsets have GPS and Glonass receive capability. More modern ones will add Baidu especially chipsets targeting Chinese market phones.

My 2023 vintage phone does GPS, Glonass, Baidu and Gallileo. I'm in a downstairs room about 1m from a window looking West. Time to first fix was 16secs, 42 sats (GPS, Glonass, Baidu, Gallileo) are visible and 7 are in use. It's telling me that I have a 17m accuracy in the fix. Not bad for indoors.

[Theo]

I'd guess this is a difference between a phone and a satnav, either a dedicated Tomtom or an in-car satnav. They might be old enough to only use GPS, and a satnav in a 10-20 year old car maybe even slower to lock (old GPS receivers could take 1 minute+).

The phone will also have A-GPS where it uses the cell towers for coarse positioning data so it doesn't need to do a full lock from scratch.

Theo Theo

[mm0fmf]

Narrow area GPS disruption is not too difficult to do as Joe Bloggs with a backpack full of techno stuff. Wide area disruption requires significant amounts of radio signal to mask the satellite signals. Wide area disruption tends to suggest state actor involvement. (High altitude aircraft/satellite based transmitters).

Three scenarios spring to mind. Like many electronic systems, your GPS could have had a brain fart and didn't correctly start up. Secondly, the sun is rather active and there is raised geomagnetic activity at present. Could have been enough activity to bugger the ionosphere causing your system to receive insufficient signals for accurate navigation. Thirdly, ISTR you live down East Anglia way where there are more than a few RAF and USAF bases. As those boys are off using up all the weapons in Yemen etc. (missiles have best before dates, so shoot 'em at someone whilst they still work!) there could well be local area disruptions to GPS near the bases.

There aren't hundreds of reports of GPS not working yesterday and papers like The Daily Hate would be blaming asylum seekers and immigrants and lefties for this outrage.

Most likely your GPS, then local disruption in the near of some military bases then solar geomagnetic disturbance.

[Andy Burns]

Any car under 6 y/o will have inbuilt 4G and GPS, so presumably will use A-GPS? (though it may not actually have satnav).