GPS satellites

ngatimozart

Super Moderator
Staff member
Verified Defense Pro
Here’s an article describing the utilization of earth’s magnetic field as an alternative to GPS. Although accuracy is 10 meters versus GPS’s 3 meters, this alternative should be less vulnerable to jamming and no worries about kit being destroyed.

Hmmm, I am a bit unsure about it. In the polar regions compasses tend to go a bit haywire. There are many localised variations in the earth's magnetosphere and even a volcanic eruption may be enough to change a localised field. 3 m accuracy with GPS? That's somewhat of an understatement. In part your accuracy is determined by how many satellites your GPS receiver can see / receive at once. At a minimum it really needs 3 and the more the better, and from memory I think that the maximum that it is able to see at any one time is 5. The thing about GPS is time and it's the time data and ephemera data encoded in the signals that's being used to determine the receiver's spatial location in 3 dimensions. Today you can generally get that down to about 1m. For accurate sub metre measurements you need fancier gear and a fixed known location to work from. I worked with gear that was accurate to +/- <1 cm and was used for surveying.

Yes we do have a problem with the probable loss of GPS, GLONASS etc., during a conflict and an alternative accurate navigation method will have to be developed. I think that something based in the quantum computing / particle /mechanics fields maybe the answer because it has to be small enough to fit into a warhead.
 

kato

The Bunker Group
Verified Defense Pro
For accurate sub metre measurements you need fancier gear and a fixed known location to work from.I worked with gear that was accurate to +/- <1 cm and was used for surveying.
Or augment GPS data with further systems like Starfire or EGNOS, typically ground-based supplement networks to GPS. Starfire in particular claims accuracies below 4.5 cm in mobile applications.

In the polar regions compasses tend to go a bit haywire. There are many localised variations in the earth's magnetosphere and even a volcanic eruption may be enough to change a localised field.
It's also rather dynamic, with the pole shifting by up to 35 MoA (!) within a year, local anomalies popping up and disappearing and the global intensity varying by up to 1% in a year.
 

ngatimozart

Super Moderator
Staff member
Verified Defense Pro
Or augment GPS data with further systems like Starfire or EGNOS, typically ground-based supplement networks to GPS. Starfire in particular claims accuracies below 4.5 cm in mobile applications.


It's also rather dynamic, with the pole shifting by up to 35 MoA (!) within a year, local anomalies popping up and disappearing and the global intensity varying by up to 1% in a year.
And the poles have a habit of flipping. I read something a whiles back that suggested that the current rate of pole shifting could be explained as a possible precursor to a pole flip. Can't remember where I read it, but that'll play havoc with a lot of things when it happens and just not anthropogenic things but other fauna that use the magnetosphere for navigation.
 
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