Russia will jamm GPS 24/7 in any conflict anyway. Why would they use it then ?
Even if they don't, if the US even suspects Russian military personel might be using civilian Navstar receivers they will turn it off in that area for the duration of the conflict.
Right now I would think part of Ratnik one will be GLONASS receivers for navigation so every Russian soldier already has access to location data from GLONASS satellites at the very least. It probably uses signals from Navstar and the other two networks but wont be dependent on them because they could be turned off without warning anyway.
AFAIK Navstar doesn't work above certain speeds and altitudes and probably would not work anywhere near an Israeli nuclear reactor or US military base in the US for instance...
I've read before that civilian GPS could be used effectively if it could be used along with a good INS for mid-course and additional guidance kits for last stage.
Inertial navigation systems use precise timers and accelerometers to measure speed and angle and drift... over time they lose accuracy but you can compensate for that. A terrain comparison guidance system looks at the target area for features like hill tops or identifyable bends in rivers or where roads fork into two or more rivers or roads. When programming a cruise missile attack you look at where the enemies known air defence systems are and so if there is a row of low hills nearby you would plan to fly on the other side of those out of view of the air defence systems. Say along the line of hills there is a river valley your missile can turn down to get to its target... the river valley is a fixed point so no matter how far the missile has flown to get there once it gets there it can now accurately pinpoint its position. If on the other side of those hills having come through the river valley there is a hard left turn and your target is right there it is an ideal way to send the missile because as the missile heads down the river valley when it gets to the end it can see its position in the air in relation to that point and calculate its exact position in 3D space... a hard left turn and the target should be right there... no need for satellite signals.
Flying down a road or river was how pilots used to navigate across country... with a map on their knee and a stopwatch they could fly on a heading for x number of seconds at y speed and work out where they should end up on the map and then look around on the map to see what should be visible from there... and so then you fly there and look to see if you can see what you should be able to see.... for instance are you between two tall peaks, or flying over a 5 road intersection... or is there a large area of planted fields to your left or whatever.
For a missile... check the air pressure and then send a super weak radio signal to the ground to determine your height above ground and with the air pressure determine your height above sea level... does that match the land height where you are currently flying.... look around you.... do the highest points of ground match the terrain around you on your digital map.... if you have a GLONASS signal check that too.
You can save the coordinates of the highly important bases or fixed target of your enemy like big early warning radars and use them at war time by uploading them at bombs computers and with the help from INS it will find their way to the targets even if the GPS was interrupted or jammed ,with additional final stage kits ,you will score a good CEP .
These days with cheap storage you can upload a complete 3D map of the terrain heights in the region and based on the location at launch from the aircraft carrying you you could work out where the target is and a useful flight path to get there... a jet powered cruise missile is just an unmanned plane really and the targeting system its autopilot.
Also using diffrential GPS would make it better .
If it is on... yes.
Most modern civilian GPS devices use both Navstar and GLONASS... because both receivers are cheap and it makes it more accurate to use both.
That's what i thought too , improving the INS and adding other guidance kits to correct the coordinates that was uploaded during launch time even if it was completely wrong .
Modern ring laser gyros are so accurate if you put it on a table it could detect the rotation of the earth. They use fibre optic cables and are very accurate...
Having points on your flight path where precision can reset the error clock to zero of course makes it even better.
Isos ,do you have any informations about the GPS guidance kit on SCALP if it use automatically the GPS military signal or it needs some kind of decryption or authentication which US only provide ? I mean if Egypt launched the SCALP now ,will it use the P code or it's not allowed by ITAR or other US shit censored and only it will use C/A code ?
I don't know, but would suspect the whole purpose of Gallieo is that either the europeans can get guaranteed access to the military Navstar codes, or they don't fully trust the US. Either way I would suspect a European missile would use both european and US GPS for better accuracy and redundancy.