Radar, sonar and other modern military sensors

The Mk-99 illuminator can illuminate up to four targets at once if the targets are close enough together in azimuth and altitude, through a multiplexing technique. This has been the case since the first Ticonderoga went to sea. In a saturation attack it would be expected there to be sufficient targets inbound on the same azimuth at roughly the same altitude to make this technique workable. Target illumination is only for the final second of the engagement or less, not more. Mid course updates transmitted to each missile's inertial nav via the AN/SPY-1 antennas can bring the missile close enough to the target to make longer time illumination unnecessary.
Wolvie, the strap on IR sensor on SM-2 is not so effective, or necessary, for use against subsonic sea skimmers. It is there for tracking sea skimming supersonic missiles, who's heat signature will often give them away before they emerge over the horizon. Such missiles have extremely high airframe temperatures that make IR homing very accurate and reliable. We fly these successfully against Vandal and Coyote targets, both of which exceed Mach 2 at 15 foot altitudes in calm sea states. SM-2 and RAM are both very effective against such targets.
Btw, we fly stream raids of multiple targets against ships as part of their training.

Re: How Do You Sink A Carrier?

Ambivalent said:

The Mk-99 illuminator can illuminate up to four targets at once if the targets are close enough together in azimuth and altitude, through a multiplexing technique. This has been the case since the first Ticonderoga went to sea. In a saturation attack it would be expected there to be sufficient targets inbound on the same azimuth at roughly the same altitude to make this technique workable. Target illumination is only for the final second of the engagement or less, not more. Mid course updates transmitted to each missile's inertial nav via the AN/SPY-1 antennas can bring the missile close enough to the target to make longer time illumination unnecessary.

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Let's see a source. BTW, you are not a source. No offense, but I don't care what you claim that you've seen or done in the military. The Naval Institute Guide does not make ANY of the claims above, including how many targets the SPG-62 can illuminate or how long a target requires illumination. The only possibly relevant information it gives is for the SPG-62's predecessor, the SPG-51 (on pp. 320-322 of the 5th Edition), which has an illumination angle of "0.9 degrees" and a range of "200kyd", which I will assume is similar to the SPG-62. Any enemy missiles within that narrow arc and within range will be lit up, be it 1,2 or 100 quadrillion missiles. In real life 1 or perhaps a few missiles could be simultaneously lit up, but stating a specific number like "4" betrays an improper understanding of what an illuminator does. Especially a radar that is mechanically slewed both vertically and horizontally like the SPG-62, there is no way in hell you could possibly make 4 targets that cannot all fit inside that narrow illumination cone to be lit up even nearly simultaneously, like what a time-sharing PESA does. That illuminator will have to stay on target until interception occurs before it can slew over to cover any additional targets outside of its initial illumination cone. Perhaps you're confusing "illumination" with "tracking", which would also be wrong because the SPG-62 doesn't have the ability to track either.

Ambivalent said:

Wolvie, the strap on IR sensor on SM-2 is not so effective, or necessary, for use against subsonic sea skimmers. It is there for tracking sea skimming supersonic missiles, who's heat signature will often give them away before they emerge over the horizon. Such missiles have extremely high airframe temperatures that make IR homing very accurate and reliable. We fly these successfully against Vandal and Coyote targets, both of which exceed Mach 2 at 15 foot altitudes in calm sea states. SM-2 and RAM are both very effective against such targets.
Btw, we fly stream raids of multiple targets against ships as part of their training.

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Again, let's see a source.

Try attacking OTH targets without the IR sensor. For targets within radar coverage, the missile can choose between the IR sensor or the radar illumination and decide which to use, but for OTH targets, there is no radar illumination, leaving the IR sensor the only thing an SM-2 has to go by (and it would have to be updated and sent to its target basket by the SPY-1 based on information gathered from AWACS), and that's been the whole point of talking about the IR sensor in the current carrier debate.

Re: How Do You Sink A Carrier?

Wolverine said:

Let's see a source. BTW, you are not a source. No offense, but I don't care what you claim that you've seen or done in the military. The Naval Institute Guide does not make ANY of the claims above, including how many targets the SPG-62 can illuminate or how long a target requires illumination. The only possibly relevant information it gives is for the SPG-62's predecessor, the SPG-51 (on pp. 320-322 of the 5th Edition), which has an illumination angle of "0.9 degrees" and a range of "200kyd", which I will assume is similar to the SPG-62. Any enemy missiles within that narrow arc and within range will be lit up, be it 1,2 or 100 quadrillion missiles. In real life 1 or perhaps a few missiles could be simultaneously lit up, but stating a specific number like "4" betrays an improper understanding of what an illuminator does. Especially a radar that is mechanically slewed both vertically and horizontally like the SPG-62, there is no way in hell you could possibly make 4 targets that cannot all fit inside that narrow illumination cone to be lit up even nearly simultaneously, like what a time-sharing PESA does. That illuminator will have to stay on target until interception occurs before it can slew over to cover any additional targets outside of its initial illumination cone. Perhaps you're confusing "illumination" with "tracking", which would also be wrong because the SPG-62 doesn't have the ability to track either.


Again, let's see a source.

Try attacking OTH targets without the IR sensor. For targets within radar coverage, the missile can choose between the IR sensor or the radar illumination and decide which to use, but for OTH targets, there is no radar illumination, leaving the IR sensor the only thing an SM-2 has to go by (and it would have to be updated and sent to its target basket by the SPY-1 based on information gathered from AWACS), and that's been the whole point of talking about the IR sensor in the current carrier debate.

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Wolvie, are you familiar with what is called Interrupted Continuous Wave Illumination? The AN/SPG-62 Illuminator is an ICWR illuminator. The principal with CW radars is they measure doppler shift in a moving target. They don't measure range. If frequency modulation is introduced, range can be measured.
With interrupted CW, the idea is that a missile doesn't need a continuous homing signal to generate an intercept course that will bring close enough to the target to put it within the blast radius of the missile's warhead. Remember, these missiles home using what is called proportional navigation. They are not line of sight homing, the guidance system calculates an intercept course to the target by trying to achieve a constant N value, the navigational constant in the proportional homing equation. Now, if this N value can be calculated from a less than continuous signal, say only 25% of the time, then the illuminator can provide a homing signal to other missiles. The number I quoted, four targets per illuminator, comes out of the 1981/82 edition of Combat Fleets of the World, in the US Navy section where the Aegis system is described. On the same pages the then proposed Burke Class DDG's are described.
Page 30 of this older document describes the principle of ICWI. This is how the AN/SPG-62 operates.



This file from Raytheon describing ESSM supports this:



Now lets look at the geometry of an anti-ship missile attack. If a single DD fires four to eight missiles at a target, say a Sovremenny firing a half or full salvo at the notional CVN, all the missiles would originate from a very small point in space defined by the movement of the ship during the time between the launch of the first and last missile. The defending ship will see a stream raid of incoming missiles all on roughly the same azimuth. Some might go high, and some might stay low, but until terminal maneuvers are attempted. there will almost always be more than one missile on a single azimuth. The beam of the AN/SPG-62 can illuminate more than one missile under these circumstances. The maximum number depends on the geometry of the engagement and is apparently limited to four.
If you want to read further, there are documents on line describing the development of ESSM that mention having to change the guidance algorithms to accommodate ICWI and mid course inertial guidance when used with Aegis.

Re: How Do You Sink A Carrier?

Oh, by the way Wolvie, Thales is advertising it's latest ICWI having the ability to illuminate 32 targets similtaneously.
All of this becomes moot in about two years when SM-6 enters service with active terminal homing ( basically an AMRAAM seeker modified for the control algorithms of a Standard missile ).

Re: How Do You Sink A Carrier?

Ambivalent said:

Wolvie, are you familiar with what is called Interrupted Continuous Wave Illumination? The AN/SPG-62 Illuminator is an ICWR illuminator. The principal with CW radars is they measure doppler shift in a moving target. They don't measure range. If frequency modulation is introduced, range can be measured.
With interrupted CW, the idea is that a missile doesn't need a continuous homing signal to generate an intercept course that will bring close enough to the target to put it within the blast radius of the missile's warhead. Remember, these missiles home using what is called proportional navigation. They are not line of sight homing, the guidance system calculates an intercept course to the target by trying to achieve a constant N value, the navigational constant in the proportional homing equation. Now, if this N value can be calculated from a less than continuous signal, say only 25% of the time, then the illuminator can provide a homing signal to other missiles. The number I quoted, four targets per illuminator, comes out of the 1981/82 edition of Combat Fleets of the World, in the US Navy section where the Aegis system is described. On the same pages the then proposed Burke Class DDG's are described.
Page 30 of this older document describes the principle of ICWI. This is how the AN/SPG-62 operates.

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This file from Raytheon describing ESSM supports this:

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Now lets look at the geometry of an anti-ship missile attack. If a single DD fires four to eight missiles at a target, say a Sovremenny firing a half or full salvo at the notional CVN, all the missiles would originate from a very small point in space defined by the movement of the ship during the time between the launch of the first and last missile. The defending ship will see a stream raid of incoming missiles all on roughly the same azimuth. Some might go high, and some might stay low, but until terminal maneuvers are attempted. there will almost always be more than one missile on a single azimuth. The beam of the AN/SPG-62 can illuminate more than one missile under these circumstances. The maximum number depends on the geometry of the engagement and is apparently limited to four.
If you want to read further, there are documents on line describing the development of ESSM that mention having to change the guidance algorithms to accommodate ICWI and mid course inertial guidance when used with Aegis.

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OMG this is funny. Please explain to me how you did not just completely shoot yourself in the foot by providing this reference. Metaphorically speaking, this is more like blowing off your own head. Did you even really understand what p. 30 is saying?

The fire control radars that are now used as illuminators, including Aegis, employ a large mechanical antenna to generate a simple "pencil beam" of electromagnetic energy that illuminates a single target. The large antenna that forms this narrow beam must be precisely stabilized to compensate for both the ship's and the target's motion. Because of its large inertia, the mechanical antenna cannot be used as an ICW multi-target illuminator.

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(my bold)

This is EXACTLY what I just said in a previous post, and it is clearly in reference to the mechanically skewed SPG-62 that is CURRENTLY present on all Aegis warships. You clearly understand neither ICWI, nor agile beam steering, nor even the general principles of target illumination. Read further along that first reference. The capabilities of ICWI and agile beam steering are capabilities to be achieved on the DDX ("DDGX" in that reference), and only possible with ESA type radars. The relatively slow mechanical steering of the SPG-62 in comparison to what SPY-1, SPY-3 and APAR can do electronically means, as I already said, that there is no way in hell it can slew between 2 targets in a near continuous manner to allow for sufficient target illumination to occur, to speak nothing of 4. OTOH if that narrow illumination cone, which at "200kyd" range is actually about 3.1km in diameter (based on a 0.9 degree spread), encompasses more than 1 incoming missile, then that pencil beam will be illuminating multiple targets simultaneously, but certainly not because it has any kind of ability to employ ICWI by means of agile beam steering.

The fact that ESSM is compatible with both CWI (SPG-62 type radars) and ICWI (APAR, SPY-3, and other ESA's) is another shot in your own foot, and certainly does not in any way imply that the SPG-62 itself uses ICWI. In fact The Naval Institute Guide EXPLICITLY states that both the SPG-51 (p. 320) and the SPG-62 (p. 322) use CWI. You can't get more wrong than that kind of direct and authoritative contradiction of your claims.

Ambivalent said:

Oh, by the way Wolvie, Thales is advertising it's latest ICWI having the ability to illuminate 32 targets similtaneously.
All of this becomes moot in about two years when SM-6 enters service with active terminal homing ( basically an AMRAAM seeker modified for the control algorithms of a Standard missile ).

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That's right, Ambie. That's because it's an ESA, and they can do things like that.

Jeff Head said:

Just the same, Ambivalent is giving a good education based on existing documentation from older systems that is available for those willing to look and research. For those who know, it is clear where the current systems are in advance, and in relation of those older ones.

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LOL

Re: How Do You Sink A Carrier?

That is correct. Pulse, CW, ICW, FMCW, forms are irrelevant to tracking ability.

A mechanical parabolic antenna, which only has a single point of focus, can only illuminate one single target at real time.

Re: How Do You Sink A Carrier?

Wolvie, the illuminator does not move physically between targets. The geometry of the targets has to be such that more than one falls inside the beam, which is a parabolic shape. Geometry is important, but in saturation attacks, or stream raids for a single azimuth, this is possible. The guidance signal is altered for each missile being directed. This was the first application of ICWI in operational use and was introduced with the Ticonderoga class.
ICWI capability was introduced to the Standard Missile family with RIM-66K-L, more often known as SM-2 Block IIIA. This is the Aegis variant that has been around for decades. Aegis uses ICWI for terminal guidance.

Re: How Do You Sink A Carrier?

Ambivalent said:

Wolvie, the illuminator does not move physically between targets. The geometry of the targets has to be such that more than one falls inside the beam, which is a parabolic shape. Geometry is important, but in saturation attacks, or stream raids for a single azimuth, this is possible. The guidance signal is altered for each missile being directed. This was the first application of ICWI in operational use and was introduced with the Ticonderoga class.
ICWI capability was introduced to the Standard Missile family with RIM-66K-L, more often known as SM-2 Block IIIA. This is the Aegis variant that has been around for decades. Aegis uses ICWI for terminal guidance.

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OMG I can't believe you are still arguing about this. You are so blatantly wrong it's getting more embarassing for you with every post and has all but completely shattered any credibility you may have had as some kind of military 'insider'. NOWHERE in that link does it state that Aegis uses ICWI for terminal guidance. It states that SM-2 Block III is capable of ICWI (just as the ESSM is), and it should be, because many countries which use the SM-2 have been moving toward ESA's, the only types of radars with this capability. The US itself will have this capability with the Dual Band Radar, specifically the X-band one. Your ridiculous refusal to accept the plain statement of your OWN source as well as the plain statement of the Naval Institute Guide now has you flying in the face of reality. Incidentally Googlebooks has the 5th edition online, so you can actually physically read the print yourself if you still want to front like you know what you're talking about. Here, let me help you:



One more time, since it seems to be a slow process for you: only CWI illumination is possible for mechanically steered radars like the SPG-62 because it is physically incapable of the agile beam steering that is required to time-share 2 different targets and provide targeting information via ICWI. The SPY-1 actually tracks its targets via this method, but since it is S-band it is not capable of the resolution required to directly provide illumination for the SM-2, which is why it has to hand off target information over to the slaved X-band SPG-62 for terminal illumination. Other ESA's like the Dutch APAR, an X-band AESA radar, can provide both tracking and illumination for their SM-2's, and do not require any dedicated FCR's to do this. Consequently..... they don't have any on their ships.

Incidentally AESA's DON'T actually HAVE to use ICWI, but do so probably for reasons of efficiency. The reason is because AESA's can form multiple simultaneous independent beams assigned to different missions (volume search, surface search, low-speed tracking, high-speed tracking, low RCS tracking, illumination, etc.), whereas a PESA like the SPY-1 can only form one single beam (per panel) which is used to track hundreds of targets nearly simultaneously via a time-sharing manner. If the SPY-1 were X-band and intended to be used in both tracking and illumination, time-sharing (ICWI) is how it would illuminate its targets. Unfortunately for you, the SPY-1 hands off targeting data to the SPG-62, which is a mechanically skewed, CWI radar.

Re: How Do You Sink A Carrier?

Wolverine, ICWI capability in SM-2 pre-dates any shipboard AESA. It dates to the 1980's when SPY-1 was state of the art and no other navy had even a passive electronically scanned radar, much less an AESA.
Again, you do not need agile beam steering or an AESA to achieve the early form of ICWI used by AN/SPG-62. Yes, the geometry is very narrow, you have to have the incoming targets in the same fairly narrow beam, but the USN knew that in a saturation missile attack by the Soviets there was a very high probability this geometry would be realized. ICWI is achieved by using different freqs for each SM-2, and dividing the time assigned to each missile. The resulting information each SM-2 receives is adequate to get the missile close enough to the target ( sufficiently accurate N calculation ) that the target will be inside the blast radius of the SM-2's warhead.

Re: How Do You Sink A Carrier?

There is no reason why you need ICW on the missile guidance itself. It is the main radar unit itself that needs it, and ICW is plainly redundant because you already have a pulse radar (SPY-1). Missile guidance doesn't rely on range information, it relies on unambiguous speed information which is provided already by CW.

The reason why APAR needs ICW---and it is the APAR that needs it, not the missile---is because APAR is not a pulse radar and therefore needs a system to obtain range. ICWI is intended to kill two birds with one stone---provide speed information for the missile guidance, while providing range information for the home radar set.

Having ICW on SPG-62 is possible but it is redundant and useless because SPY-1 is already a pulse radar and gets range info from the pulses. Putting ICW compatibility with SM-2 was intended for use from the beginning with non pulse search & tracking radars. AESA is not needed for ICW creation, but it still requires a specialized radar set with separate transmitters and receivers. If you put ICW on SPG-62, who is going to receive and process the range information? Not the missile itself, which only needs to recognize the signal, but not process the range information.

Again I repeat, ICWI is a shortcut between Pulse + CW. You don't need ICWI when you have already have pre-existing Pulse + CW sets. You want ICWI only when you consolidate two radar set functions into a single set, mainly tracking and illumination.