measurements of 3x gyroscopes, which determine the orientation of 3x accelerometers. In turn the accelerometers' measurements are used to estimate the missile's velocity and position.
Sorry, this is so technical - I am trying to keep it simple, but INS are a highly complex
3/n
Sorry, this is so technical - I am trying to keep it simple, but INS are a highly complex
3/n
system, which uses tons maths and physics.
GMLRS missiles use 3x Ring Laser Gyroscopes (RLG) (or Interferometric Fiber Optic Gyroscopes (IFOG) if the US Army's plan to replace RLGs with cheaper IFOGs has succeeded).
Anyway: you can't jam RLGs or IFOGs. Light would have to
4/n
GMLRS missiles use 3x Ring Laser Gyroscopes (RLG) (or Interferometric Fiber Optic Gyroscopes (IFOG) if the US Army's plan to replace RLGs with cheaper IFOGs has succeeded).
Anyway: you can't jam RLGs or IFOGs. Light would have to
4/n
The reason is that the US doesn't want China or Russia to reverse-engineer the US militaries' RLGs, IFOGs, MEMS accelerometers, navigation processors, etc, which are 20 years ahead of what China and Russia can build.
So, while we know how a GMLRS INS works, the specifics
6/n
So, while we know how a GMLRS INS works, the specifics
6/n
are unknown.
Back to the MEMS accelerometers, which measure a change in electrical capacitance in response to acceleration. To jam them gravity and electricity would have to stop working in the universe.
russia can only jam an INS by smashing it with a hammer in mid-flight.
7/n
Back to the MEMS accelerometers, which measure a change in electrical capacitance in response to acceleration. To jam them gravity and electricity would have to stop working in the universe.
russia can only jam an INS by smashing it with a hammer in mid-flight.
7/n
A GMLRS INS is accurate to a CEP of 7 m. Adding GPS measurements improves that to a CEP of 5 m.
But can the russia jam GPS? Depends on which GPS, because there are actually two: SPS and PPS.
SPS or Standard Positioning Service is what civilians get.
8/n
But can the russia jam GPS? Depends on which GPS, because there are actually two: SPS and PPS.
SPS or Standard Positioning Service is what civilians get.
8/n
SPS uses the single frequency C/A-Code and russia has succeeded in jamming and spoofing it.
PPS or Precise Positioning Service uses the encrypted dual frequency P/Y-Code. PPS is more accurate than SPS and has significant performance advantage due to the double frequency use.
9/n
PPS or Precise Positioning Service uses the encrypted dual frequency P/Y-Code. PPS is more accurate than SPS and has significant performance advantage due to the double frequency use.
9/n
And thanks to its encryption PPS can't be spoofed. russia has tried continuously to jam PPS, but it never succeeded.
In short: unlike what russian propaganda and fanboys say, GMLRS rockets can't be jammed and can't be shot down. Once fired they never miss.
10/end
In short: unlike what russian propaganda and fanboys say, GMLRS rockets can't be jammed and can't be shot down. Once fired they never miss.
10/end
PS: for those with a desire for all the physics, maths and details:
@JHUAPL article about: "Inertial Navigation for Guided Missile Systems":
jhuapl.edu
@NATO paper about: "Inertial Navigation Sensors"
sto.nato.int
@JHUAPL article about: "Inertial Navigation for Guided Missile Systems":
jhuapl.edu
@NATO paper about: "Inertial Navigation Sensors"
sto.nato.int
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