Question regarding naval air defence (illumination, missile guidance)

H

harishkumar09

New Member
Totoro, could you tell me why we need illumination of the target during the final leg of an attack?

At least while engaging far-off targets, most targets (aircraft) would be within the cone of the tracking radar. If it is a stationary mechanical radar, it will continuously receive reflected energy from the attacking aircraft and using coordinates thus obtained can plot a trajectory using the computer. Once SAMs are launched the energy is going to be reflected from the SAMs as well so the tracking radar now has coordinates of both outbound missiles and inbound targets. It can now easily send guidance commands by radio to the missiles and put them on a collision course towards the target. Why do we need the illuminating radars to paint the target?

Why do we need the illuminating radars which place a limit on the number of targets engaged?

Can't the tracking radar guide all missiles in its cone, to all the targets within the cone till collision?

Thank You.
Harish.
 
T

Totoro

Major
VIP Professional
Some systems do just that. Various land SAM systems, like Patriot or S300 do it like that, with tracking radar being the only one emitter in the loop. Some ship based SAM systems also do it like that. Thales' APAR system on german and dutch frigates has a single array both for tracking and terminal illumination.

The reason why US ships have separate arrays is that a single array has limitations. To be able to precisely guide the missiles in the terminal stage, it needs precision. Which means X band (or perhaps high C band, but Patriot is only one that uses that). On the other thand, X bands have issues with power and range. Having a separate array for tracking means one can use a lower band array, like the S band SPY radars use. Such bands are a fine choice for many roles, including early warning volume search. Which is why US ships don't really use any other arrays for volume search. The aforementioned european frigates on the other hand need to use another array, not for terminal illumination, but for volume search, which is why they have an additional L band radar.
 
H

harishkumar09

New Member
Totoro said:
Some systems do just that. Various land SAM systems, like Patriot or S300 do it like that, with tracking radar being the only one emitter in the loop. Some ship based SAM systems also do it like that. Thales' APAR system on german and dutch frigates has a single array both for tracking and terminal illumination.

The reason why US ships have separate arrays is that a single array has limitations. To be able to precisely guide the missiles in the terminal stage, it needs precision. Which means X band (or perhaps high C band, but Patriot is only one that uses that). On the other thand, X bands have issues with power and range. Having a separate array for tracking means one can use a lower band array, like the S band SPY radars use. Such bands are a fine choice for many roles, including early warning volume search. Which is why US ships don't really use any other arrays for volume search. The aforementioned european frigates on the other hand need to use another array, not for terminal illumination, but for volume search, which is why they have an additional L band radar.
Click to expand...

My question is why do we even need an engagement radar/illumination radar? Isn't the tracking radar more than enough? If the Patriot can do with just a tracking radar, why not other systems?
 
shen

shen

Senior Member
harishkumar09 said:
Totoro, could you tell me why we need illumination of the target during the final leg of an attack?

At least while engaging far-off targets, most targets (aircraft) would be within the cone of the tracking radar. If it is a stationary mechanical radar, it will continuously receive reflected energy from the attacking aircraft and using coordinates thus obtained can plot a trajectory using the computer. Once SAMs are launched the energy is going to be reflected from the SAMs as well so the tracking radar now has coordinates of both outbound missiles and inbound targets. It can now easily send guidance commands by radio to the missiles and put them on a collision course towards the target. Why do we need the illuminating radars to paint the target?

Why do we need the illuminating radars which place a limit on the number of targets engaged?

Can't the tracking radar guide all missiles in its cone, to all the targets within the cone till collision?

Thank You.
Harish.
Click to expand...

The engagement profile you described is called command guidance. Many SAM systems do use that and it is probably the cheapest. Command guidance works best at short range. Short range SAM such as TOR, Crotale, etc are command guided. But as the range gets longer, the accuracy of the tracking radar becomes worse. Long range command guided missile usually need very large warhead to compensate for the loss in accuracy at range. With SARH on the other hand, as the range increases, the receiver on the missile is getting closer to the target, so the accuracy increases with range. That's also true for Track-via-Missile and ARH.
 
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