how could aegis deal with targets which are under horizon?

big toothbrush said:

my question is how could aegis deal with targets which are under horizon. how could the AN/SPG-62 FCS illuminate the targets since they are in its dead angle. aegis could be supported by other sensor units such as AWACS through data links, but still, AN/SPG-62 must offer illuminating. unless AWACS can do this job for FCS, otherwise i'm confused.

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My goodness. You're asking for classified information. Nobody's going to tell you the answer to this question. It's one thing to give you a general idea of how the system works(And it does real well), but you're asking something that will not be answered.

Sczepan said:

The question is:
how could aegis (like the Type 052C Lanzhou Class DDG) deal with targets which are under horizon?

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the HQ-9 SAM carried by 052c has an active seeker, no need ship based illuminaters, it can guide itself in the end of trip. with targets' informations transfered from AWACS or other sensor units through datalinks, HQ-9 can deal with over-horizon targets for sure.

Sea Dog said:

My goodness. You're asking for classified information. Nobody's going to tell you the answer to this question. It's one thing to give you a general idea of how the system works(And it does real well), but you're asking something that will not be answered.

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classified information? are you kidding? this is just basic knowledge and every has right to know it.

big toothbrush said:

classified information? are you kidding? this is just basic knowledge and every has right to know it.

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No sir. You asked specific questions related to how the illuminator for the US Aegis battle management system identifies targets in certain regions. That is specific and classified info. And you have no business knowing it. And as such, you will not get your question answered.

i hope this helps you
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big toothbrush said:

the HQ-9 SAM carried by 052c has an active seeker, no need ship based illuminaters, it can guide itself in the end of trip. with targets' informations transfered from AWACS or other sensor units through datalinks, HQ-9 can deal with over-horizon targets for sure.


classified information? are you kidding? this is just basic knowledge and every has right to know it.

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HQ-9 will have serious trouble with under the horizon targets, because it's minimum operating altitude is like 500m.

I'd think most SAMs would be using active seekers.

swimmerXC said:

i hope this helps you
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thanks alot. i've gotten the answer from an expert already. "The block SM-2 IIIB is an inertial + update missile for most of its flight like earlier SM2 rounds. However, terminal guidance can be via an imaging infrared seeker, the semi-active RF seeker or preferably both. Using a combination of RF and IR homing, the SM-2MR IIIB is very accurate. In fact during a test shot, where the missile did not carry a warhead but a telemetry unit, the missile physically contacted the target. In certain scenarios when the RF track was lost or could not be acquired IR homing alone will be the back up homing mode. Hence, if the missile can be guided close enough to the target to put the target within its IR homing basket, it can hit hit even if the target is obscured from the line of sight of the ship's illuminators or if the RF feedback is effectively jammed. However, the IR seeker's homing basket is much smaller than the semi-active RF seeker's and is smaller than an active missiles, and guiding the missile through command updates close enough to the target will more difficult than with an active radar seeker."

just use imaging infrared to instead of semi-active radar in the end. but only can deal with one target at the same time because infrared guidings all are passive track mode.

tphuang said:

HQ-9 will have serious trouble with under the horizon targets, because it's minimum operating altitude is like 500m.

I'd think most SAMs would be using active seekers.

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this 500m is obviously nonsense though it mentiond everywhere. SAM's minimum operation height is only decided by its detonator trigger range. an average number is about 8~15m. missile just can't fly lower than this, otherwise its detonator whould recognize sea surface as target and trigger the warhead. as experts said instead of unnprofessional resources, HQ-9's minimum operation height is around 8~15m indeed.

most SAMs such as SM-2/3, PAC-2/3 and S-300's 48N6 missile use INs/orders update model plus semi-active seeker. there are advantages to a semi-active seeker. this is because a semi-active missile has a much larger homing basket than an active one and it is easier to deal with ECM when you have a powerful illuminator than when the missile has to rely on an active seeker 1/100th the power output. so HQ-9 still keep the ability to be guided under semi-active track model.

big toothbrush said:

this 500m is obviously nonsense though it mentiond everywhere. SAM's minimum operation height is only decided by its detonator trigger range. an average number is about 8~15m. missile just can't fly lower than this, otherwise its detonator whould recognize sea surface as target and trigger the warhead. as experts said instead of unnprofessional resources, HQ-9's minimum operation height is around 8~15m indeed.

most SAMs such as SM-2/3, PAC-2/3 and S-300's 48N6 missile use INs/orders update model plus semi-active seeker. there are advantages to a semi-active seeker. this is because a semi-active missile has a much larger homing basket than an active one and it is easier to deal with ECM when you have a powerful illuminator than when the missile has to rely on an active seeker 1/100th the power output. so HQ-9 still keep the ability to be guided under semi-active track model.

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right, you know it would be nice if you actually have some sources to back this up. Most sources state 500m for HQ-9. I don't know if it's true or not, but that's all that is available. Until further information is available, I'd have to use it.

tphuang it seems that you just pluck numbers out of open source and never ask the WHY and the HOW.

you don't have an engineering background, do you?

toothbrush or whatever his name is is perfectly correct when he said that the minimum altitude of a missile only depends on the effective radius of the fuse.

However, if you want to talk about systems, then you have to factor in radar horizon and ground clutter. Also, the capabilities of the seeker itself.

the biggest weakness in toothbrush's argument, and one which you did not exploit, is that since HQ-9 is active (assumed) in terminal stage, you have to take ambient interference into account.

Do you honestly think the air density at sea level and 500m above sea level or the relative humidity matters THAT much as to render a missile COMPLETELY USELESS? If you do, then give a reason.

vincelee said:

tphuang it seems that you just pluck numbers out of open source and never ask the WHY and the HOW.

you don't have an engineering background, do you?

toothbrush or whatever his name is is perfectly correct when he said that the minimum altitude of a missile only depends on the effective radius of the fuse.

However, if you want to talk about systems, then you have to factor in radar horizon and ground clutter. Also, the capabilities of the seeker itself.

the biggest weakness in toothbrush's argument, and one which you did not exploit, is that since HQ-9 is active (assumed) in terminal stage, you have to take ambient interference into account.

Do you honestly think the air density at sea level and 500m above sea level or the relative humidity matters THAT much as to render a missile COMPLETELY USELESS? If you do, then give a reason.

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actually, I'm studying engineering at a very strong engineering university. Lol, I personally don't think 500m is the minimum latitude for HQ-9's naval version. I think that number probably came from the land version of HQ-9. I personally think it is closer to Rif-M's minimum altitude. However, I do not have proof for that, that's why I asked toothbrush to provide some sources to englighten me on this.

the minimum altitude of the missile depends on several factors.
1. the detection range of the radar at low altitudes
2. the ability of the active seeker in look down mode
3. the guidance software


There are too many things, I'm still waiting for some answers.