Military FAQ thread
- Thread starter rommel
- Start date
Mean what kind of ship is the Sergei Gorshkov? Its A Soviet Aircraft carrier, sort of hybrid VSTOL carrier with heavy SSM/ASW/SAM fit. Its now being converted to full breadht carrier with STOBAr arragment. As the ship is officcally decommisioned form the Russian navy, the name is to be given to the new pr. 22235 class frigates under development.
If you were wondering the name, it comes from Admiral Sergei Gorshkov, the longest running head of the Soviet Navy. He followed the legendary Admiral Kuznetsov who was discharged due political reasons in 1956. Gorshkov was in charge of the fleet untill late 80's.
Question about SD-10 Missile
Hi all,
haven't posted here for a LONG time, don't have too much time to browse the forums, but there is interresting thread regarding the Chinese Fighters.
So The question about the SD-10 concern the guidance, does it will be able to use a similar mode as the HOJ (Home On Jam, the missile follows a radar jamming source) which is available on AIM-120, AIM-7P and last R-27 ?
Hi all,
haven't posted here for a LONG time, don't have too much time to browse the forums, but there is interresting thread regarding the Chinese Fighters.
So The question about the SD-10 concern the guidance, does it will be able to use a similar mode as the HOJ (Home On Jam, the missile follows a radar jamming source) which is available on AIM-120, AIM-7P and last R-27 ?
Yes it can.
The radiated noise can be picked up by sonar and then be classed by the sonar-operators, lately to some extent by modern computers. The operators rely on a huge database of vessels to make a decision. They can count number of screws, number of blades on each screw and how many turns it makes (geussing on the targets speed). The frequence of the power system and so on. Depending on how clear the signal is.
Then they can determine the targets tracjorety. This is called target motion analysis, ot TMA. You constantly meassure the bearing to your target. And you also know your own speed and direction. Here it is importand to follow a zig-zag course to change the aspect to the target.
I think it it's considered that the target has a constant speed and heading.
Now, through the different target bearings over time, you have a relative movement of the target against your own. Now it's possible to approximately meassure the targets speed and heading using mathematical algorythms in a cartesian coordinate system (or more accurate two overlapping each other, I think).
Now that you have a rough first tracjorety, you can do this all over again getting more and more accurate.
If you can track that target long enough, I think it should be accurate enough to get a valid firing solution for a torpedo.
The radiated noise can be picked up by sonar and then be classed by the sonar-operators, lately to some extent by modern computers. The operators rely on a huge database of vessels to make a decision. They can count number of screws, number of blades on each screw and how many turns it makes (geussing on the targets speed). The frequence of the power system and so on. Depending on how clear the signal is.
Then they can determine the targets tracjorety. This is called target motion analysis, ot TMA. You constantly meassure the bearing to your target. And you also know your own speed and direction. Here it is importand to follow a zig-zag course to change the aspect to the target.
I think it it's considered that the target has a constant speed and heading.
Now, through the different target bearings over time, you have a relative movement of the target against your own. Now it's possible to approximately meassure the targets speed and heading using mathematical algorythms in a cartesian coordinate system (or more accurate two overlapping each other, I think).
Now that you have a rough first tracjorety, you can do this all over again getting more and more accurate.
If you can track that target long enough, I think it should be accurate enough to get a valid firing solution for a torpedo.
szbd
Junior Member
I see, thanks. So it seems impossible for a helicopter with dipping sonar to locate a sub under water by passive means, if the helicopter doesn't move? Then how about active sonar?
Correct. However, I think it's a standart method anyway that a helo gets to a certain point, dips it's sonar in the water, meassures a signal, retracts the sonar, moves several hundred or thousand feets, stops again and does it again.
And this several times in a row. Lets you fix the sub approximately.
Besides, a helo can drop several sonoboys -active and passive- wich "dive" to a pre-programed depth, meassure sound-signals and transmit those back to the helo (or the mother ship), where the operator again computes a (rough) fix.
Tracking subs is a patience-game (?) It can last hours I think to get a hard fix.
Active sonar is different. When you don't have the time for a hard fix (or don't get it for any other reason) or when you have to take a snapshot, you go active. Of course that will give away your presence and a accurate bearing, since the enemy sub can hear your ping.
You listen for the return of those sonic waves. The bearing gives you the direction to the target and the time it takes the waves to travel the distance gives you the range.
Therefore it is important to know the water conditions precisely at all times. Because these (mostly temperature) determine how fast a sonic wave travels (behaves) in water.
On a side note, the thermocline layer is an important thing here. At a certain depth (depending on the coditions) you come to a point where the water temperature makes a signifcant dorp when you go just a little deeper. This is the thermocline. It causes sonic anomalies, a bit like a mirror perhaps. Subs can "hide" under (or above) it.
The probably most remarkable "counter-meassures" are active defense systems (ADS) like Trophy(Rafael and GM) and Iron Fist(IMI), perhaps there are more.
Both are designed to protect vehicles or sites from missile threats.
They have in common small radar suites that cover the close surroundings of the object. Once they tracked and identified a threat, they activate the response.
Trophy fires a small projectile on a ballistic tracjority against the incoming missile, wich I think will go off by a time trigger and throw a bunch of sub-projectiles on the incoming missile.
Iron Fist fires a projectile looking like a small smart-bomb. It will go off in close proximity to the missile. The pure blast will destabilize the thread in it's path, sharply decreasing it's danger.
Iron Fist can be mounte on even smaller vehicles (HMMWVs) than Trophy.
Israel is already mounting them on Merkava 4s I think, and the US might introduce them with FCS and refitt them to M1A2s, Stryker etc. in about two years, AFAIK.
The intercept will occur 10-30m out from the platform.
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well i did heard about the trophy. Does China have anything like this kind of active defence??
on another question, i was wondering about the external fuel tanks on jet fighters. Does it consume all of the external tank first first and drop it one by one or wait all of them to be empty and drop it