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[Paphitis]

Yes it can navigate over the sea, with Inertial Navigation.

TERCOM is only for Vertical Navigation but it can also navigate horizontally through 3D countour modeling of the terrain providing that the modelling is entered into its data base which it should be. It then plots itself on the map and cross checks with INS and GPS or INS alone.

TERCOM, INS and GPS are completely independent but TERCOM is mainly used as a terrain radar so that the Missile, or Tornado or F-111 can adjust its altitude. It doen't follow contours just works out how high it should be and it can plot itself on a 3D model or contour map. It's a terrain following map.

Over the ocean, it simply would detect the terrain as Sea Level and adjust its altitude accordingly. If the Missile flies over the Troodhos, then the TERCOM will increase its altitude and follow the contours of the terrain so that it doesn't hit the ground until it gets over the peak and then it will follow the contours back down as it passes over the other side by decreasing its altitude.

INS is completely self contained. Inertial Nav is accurate to within a few metres, on its own.

GPS relies on a constellation of satellites for its accuracy. The US military will have pretty much dead on accuracy. Civilian use of GPS has triangulation errors which means its not as accurate and the Americans dfo that so n one can use their satellite Constellation against them (such as terrorists). But its still pretty accurate.

Cruise Missiles are not reliant on GPS alone. Even though the chances of GPS getting hacked by anyone or jammed has never happened before. If it does happen, it would cause mayhem because aircraft on RNAV Approaches would start to fly into mountains and buildings. Civil Aviation would be bought to its knees.

[Pyrpolizer]

Yes it can navigate over the sea, with Inertial Navigation.

TERCOM is only for Vertical Navigation but it can also navigate horizontally through 3D countour modeling of the terrain providing that the modelling is entered into its data base which it should be. It then plots itself on the map and cross checks with INS and GPS or INS alone.

TERCOM, INS and GPS are completely independent but TERCOM is mainly used as a terrain radar so that the Missile, or Tornado or F-111 can adjust its altitude. It doen't follow contours just works out how high it should be and it can plot itself on a 3D model or contour map. It's a terrain following map.

Over the ocean, it simply would detect the terrain as Sea Level and adjust its altitude accordingly. If the Missile flies over the Troodhos, then the TERCOM will increase its altitude and follow the contours of the terrain so that it doesn't hit the ground until it gets over the peak and then it will follow the contours back down as it passes over the other side by decreasing its altitude.

INS is completely self contained. Inertial Nav is accurate to within a few metres, on its own.

GPS relies on a constellation of satellites for its accuracy. The US military will have pretty much dead on accuracy. Civilian use of GPS has triangulation errors which means its not as accurate and the Americans dfo that so n one can use their satellite Constellation against them (such as terrorists). But its still pretty accurate.

Cruise Missiles are not reliant on GPS alone. Even though the chances of GPS getting hacked by anyone or jammed has never happened before. If it does happen, it would cause mayhem because aircraft on RNAV Approaches would start to fly into mountains and buildings. Civil Aviation would be bought to its knees.

No, it's not!
I know you frequent the aviationist forum where 99.999% of the members are apologists of the Tomahawks but even there you can hear people saying it's not accurate.
With GPS aid, yes the rocket can hit with a + or -1 m accuracy, however with INS alone there's no way to hit that accurately.

It looks you made up your mind based on INS used in commercial airlines that mostly travel in straight lines.
The Tomahawk however doesn't travel in straight line.
Still you will find that a plane traveling from Cyprus to London may end up to + or - many km from the airport assuming it depended on INS alone. Gyroscopes, are just a mechanical devices (albeit linked to electronic) and as such produce an error in every measurement. These errors add up to the next and next and the next. Depending on the number of changes in direction and the distance from the target they may end up to hundreds of meters away from target.

Now if you read the history of these missiles on Wikipedia
https://en.wikipedia.org/wiki/Tomahawk_(missile)
You will notice that they were always vulnerable to GPS-jam.

So how could this GPS-jam force the missile to possibly end up in the desert?
One very simple way is knowing the maximum deviation from position the INS computer would accept the GPS signal as been real instead of fake. In this case the jam would provide the rocket a GPS signal that is off by the maximum error accepted by the INS system. Notice the INS system always calculates the position based on the PREVIOUS position. It doesn't really know it's exact location, it's just a series of calculations each one based on the previous one. And from one position to another it accepts some error compared to the GPS signal.
Give it that error constantly and the rocket will never realize it was guided by a false GPS signal.

In any case you can look at the damage caused by those missiles. The Tomahawks alone should produce 1/330th of the damage of Hiroshima bomb 103X450/ 15 Ktons of the Hirishima bomb https://en.wikipedia.org/wiki/Little_Boy

Does the damage on just one building plus 2 abandoned airways equal to that???
Hell no!

[Get Real!]

Trump claims all hit their target so I guess 103 landed on the only building that sustained damage!

That’s 100% accuracy from 1980s junk...

[Robin Hood]

Paphitis:

INS is completely self- contained. Inertial Nav is accurate to within a few metres, on its own.

You are correct in that it is an independent stand alone system, but it is affected by outside influences. Therefore it will be for ever drifting away from the target point the moment something outside changes. With the V1, the first cruise missile, it could be bought down by clipping the wing and tipping it as this disturbed the gyro and it could not correct quick enough to recover. I agree things have moved on since then. But the principal has not changed.

INS is based on the principal of the GYRO, it changes with the attitude of the airframe three axis' and will compensate for that. To be accurate it needs information from outside. How else would you compensate for wind speed and direction, down draughts, terrain, true air speed, air pressure and ground track and even to a degree, temperature? All these can affect the airframe without disturbing the gyro and thus it affects the actual ground track, but not the gyro.

Therefore any of the missiles used would need some communication with the outside world.

Cruise Missiles are not reliant on GPS alone. Even though the chances of GPS getting hacked by anyone or jammed has never happened before. If it does happen, it would cause mayhem because aircraft on RNAV Approaches would start to fly into mountains and buildings. Civil Aviation would be bought to its knees.

They greatly rely on GPS for their accuracy. It HAS happened before in Moscow...... but you at the time thought the idea preposterous ....... but the effect it appears is local. Read what I said was reported ...... the taxis GPS was given coordinates which, had it been an aircraft/missile, would have sent it to a point many miles away from the intended target. The effect is local ......... so, jam the system at 10-15 miles to target and it could be fooled into going to the new coordinates .... which could be 30-40 miles into the desert or the sea and it is used only in a combat situation, so would not affect civil aviation.

TERCOM would stop it hitting mountains etc because that is live information.

You are far too quick to assume YOUR systems are virtually infallible and then switch to denial when strange things happen ..... like an SU-24 performing 'wings-clean' aerobatics over the USS Donald Cook in the Black Sea off Sebastopol, in 2014(?) when for some unknown reason all its systems suddenly shut down!

[Robin Hood]

Trump claims all hit their target so I guess 103 landed on the only building that sustained damage!

That’s 100% accuracy from 1980s junk...

It certainly seems that many were bought down by missiles such as Pantzir-1C and I suspect the Russian GPS jamming systems. Maybe there is a bit of exaggeration on both sides but it is obvious to anyone that the damage does not reflect Trumps rather silly claims.

[Pyrpolizer]

so, jam the system at 10-15 miles to target and it could be fooled into going to the new coordinates .... which could be 30-40 miles into the desert or the sea and it is used only in a combat situation, so would not affect civil aviation.

I think you cannot fool it like that. By the minute it's launched both GPS and INS start working separately however both systems' positioning data get compared by a computer.
if their positioning data coincides then navigation continues with GPS otherwise the INS takes over.
There's a certain (unknown) allowance of difference between the GPS data and the INS data, before the GPS data is rejected.
So if the Russians applied some kind of jamming method to misguide those missiles that should be totally different than what they did on taxis.
Assuming the Russians did such a thing I'd rather think it was a carefully controlled fake signal.

for Paphitis' info: The Tomahawks were flying for about 15 minutes

[Get Real!]

Let’s Bomb Syria to Hell Before The Truth “Blows Up” In Our Faces
https://journal-neo.org/2018/04/16/let- ... our-faces/

“New Think” and America’s Fake Gas War
https://journal-neo.org/2018/04/15/new- ... e-gas-war/

US Attacks Syria: Disregards Evidence and International Law
https://journal-neo.org/2018/04/14/us-a ... ional-law/

[Robin Hood]

so, jam the system at 10-15 miles to target and it could be fooled into going to the new coordinates .... which could be 30-40 miles into the desert or the sea and it is used only in a combat situation, so would not affect civil aviation.

I think you cannot fool it like that. By the minute it's launched both GPS and INS start working separately however both systems' positioning data get compared by a computer.
if their positioning data coincides then navigation continues with GPS otherwise the INS takes over.
There's a certain (unknown) allowance of difference between the GPS data and the INS data, before the GPS data is rejected.
So if the Russians applied some kind of jamming method to misguide those missiles that should be totally different than what they did on taxis.
Assuming the Russians did such a thing I'd rather think it was a carefully controlled fake signal.

for Paphitis' info: The Tomahawks were flying for about 15 minutes

I am not a weapons expert but surely any guidance system needs two fixed parameters? Where it is starting from and where it is going to, what is in between is a series of course corrections as GPS coordinates. Compare the desired location at any time with the actual GPS location and the computer changes the control surface parameters to remain on track.

Unless the destination is set and fixed say a 'memory stick' that cannot be accessed remotely, then it could be accessed and thus changed by an external signal? Every missile I would think would have the ability to change the target location as they can hit both stationary and moving targets? This could of course be done by the RADAR system .... if there is such a thing, but would only work in the final few seconds of the flight.

Obviously it was a fake signal, it lied to the GPS and changed the destination and that actually happened. It was well covered at the time. When they drove away from the immediate area of the Kremlin the display went back to normal. We are not talking about deviation from track but changing the final target location.

[Pyrpolizer]

I am not a weapons expert but surely any guidance system needs two fixed parameters? Where it is starting from and where it is going to, what is in between is a series of course corrections as GPS coordinates. Compare the desired location at any time with the actual GPS location and the computer changes the control surface parameters to remain on track.

Yes but at the same time it has to check whether the GPS signal is fake by comparing it with the calculated coordinates of the INS.
The INS steps in in that case. It also steps in when the GPS signal is lost-this often happens when the rocket travels between steep mountains having no direct contact with most satellites. The weakness of the INS is that it constantly does calculations to find out whether it's on route/ or on target. It has no idea if the target is there or not. It just relies on calculations and each calculation assumes the previous one was correct... Hence it may accumulate huge error especially if the GPS signal is fake but WITHIN tolerances

Unless the destination is set and fixed say a 'memory stick' that cannot be accessed remotely, then it could be accessed and thus changed by an external signal? Every missile I would think would have the ability to change the target location as they can hit both stationary and moving targets? This could of course be done by the RADAR system .... if there is such a thing, but would only work in the final few seconds of the flight.

It's not fixed but I doubt anyone other than the launcher would ever manage to communicate with it and change the target without knowing the secret codes that initiate such "conversation"

Obviously it was a fake signal, it lied to the GPS and changed the destination and that actually happened. It was well covered at the time. When they drove away from the immediate area of the Kremlin the display went back to normal. We are not talking about deviation from track but changing the final target location.

Yes I agree that's the most probable scenario, assuming of course the Russians did such a thing.
What the Americans say doesn't look reliable, but the Russians have not provided any evidence for their claims either.
For the moment I think they both lie. The question is who is the bigger liar

[repulsewarrior]

dp.