different RF missiles vs IR missiles

Read the forum code of contact

Member for

10 years 5 months

Posts: 2,014

why all RF guider missiles even the very old one can be launched in LOAL ( lock on after launch mode ) while only very few , newest IIR guider missiles can be launched in LOAL mode ? , why most of them still have to use LOBL mode ? , i dont really get it , wasnt the much higher seeker resolution of IIR missiles allow them to choose target by them self much easier than Radar guider missiles?
http://combatace.com/uploads/monthly_10_2010/post-2042-019927100%201286389385.jpg
http://www.ausairpower.net/XIMG/AIM-9X-FPA-seeker-300.png
also wasn't the old IR missiles like aim-9B , K-13A are really easy to be fool by flares , which mean they are unable to distinguish between an aircraft and a flares and choose the wrong target , but to be able to choose wrong target , they must have to ability to choose target in the first place , if they can arquire target by them self why cant they be used in LOAL mode ?
because they are LOBL ( lock before launch ) if they can't lock target after launch then they will never be fool by flares as they will stick with the orign target any way ( sorry if this a bit hard to understand , my english is not very good )

Second question : what is the IIR air to air missiles with the best seeker at the moment ?
R-74 , A-darter , Aim-132 , AIM-9X , IRIS-T , Python-5 or Mica IR

Original post

Member for

10 years 6 months

Posts: 1,760

Mainly necessity in terms of range. Historically all missiles were frontal hemisphere only and more of less dead ahead at that. IR missiles were generally short range, so only needed LOBL, whereas RF missiles were long range so required LOAL.

An exception would be the R-40T/TD employed on MiG-25s. Could well be the missile that scored the only F-15 kill.

Seems the R-24T on MiG-23s was another early LOAL IR missile.

Member for

10 years 5 months

Posts: 2,014

Mainly necessity in terms of range. Historically all missiles were frontal hemisphere only and more of less dead ahead at that. IR missiles were generally short range, so only needed LOBL, whereas RF missiles were long range so required LOAL.

An exception would be the R-40T/TD employed on MiG-25s. Could well be the missile that scored the only F-15 kill.

Seems the R-24T on MiG-23s was another early LOAL IR missile.


but i mean early IR , IIR missiles cannot even be use as LOAL , target must be locked before launch , even then AIM-9X block 1 was unable to look target after launch without software update , my question is , if they can be fool by flare then it mean they can aquire target by their own , why cant they do LOAL

Member for

16 years 6 months

Posts: 1,348

You are incorrect in thinking that all RF-guided missiles had LOAL capability. If you think about this for a moment, if the seeker of a missile is going to operate in LOAL mode, what guides the missile in the earlier stages of flight? LOAL requires that the missile has two forms of guidance, one of which is used to steer the weapon to the point where the seeker can lock on. Early radar-guided weapons such as AIM-7 Sparrow did not have a second guidance system.

As Lukos has reminded us, the R-24T R-23 and R-24 (AA-7 'Apex') series of missiles used on MiG-23 versions equipped with the Safir radar did have LOAL capability. In the early stages of flight, they used command guidance. But most LOAL weapons rely on inertial navigation system rather than command guidance, so had to await the availability of lightweight inertial technology.

The purpose of flares is to deceive a missile that has already locked onto the aircraft. The newly ejected flare makes the apparent IR target seem stronger. As an angular separation develops between the flare and the target, the idea is that the missile seeker will be fooled into tracking the flare rather than the target. There are various tricks that a seeker can use to detect a flare, such as kinematic behaviour, and IR intensity at two different frequencies, but flare designers are trying to counter these.

Member for

10 years 5 months

Posts: 2,014

You are incorrect in thinking that all RF-guided missiles had LOAL capability. If you think about this for a moment, if the seeker of a missile is going to operate in LOAL mode, what guides the missile in the earlier stages of flight? LOAL requires that the missile has two forms of guidance, one of which is used to steer the weapon to the point where the seeker can lock on. Early radar-guided weapons such as AIM-7 Sparrow did not have a second guidance system.

oh i see , but wasnt all the active radar guider missiles can do LOAL even the one without INS , while very few IR missiles can be used in LOAL mode , what the exact reason ?
EX : AGM-65 can only be used in LOBL mode while AGM-114 can be used both in LOAL and LOBL , both kind of missile dont have data link or anything other than their main seeker
AGM-122 can be used in LOAL while AIM-9 can only be used in LOBL

there are some reason ( i dont know what it is ) make it much harder for IR missile to do LOAL , this very very obvious especially with the air to ground missiles one
for example when you compared the AGM-84A/B/C/D vs AGM-84E
form same family of missile , both have INS , both are fire and forget, both can be used in LOAL mode , however :
the AGM-84 A/B/C/D can be guider to target location by INS and then it's radar will lock on target automatically which mean aircraft can launch the missiles and then flee right away , while for the AGM-84E , after it have been guided to the target location by INS , it must be locked on to target manually by pilot through data link , which mean pilot must stay in danger zone much longer
radar guider Agm-84

The missile flies at a low cruise altitude, and at a predetermined distance from the expected target position, its AN/DSQ-28 J-band active radar seeker in the nose is activated to acquire and lock on the targe

vs
AGM-84E
the AGM-84E flies a complex path to its target using its inertial system, and during the final 60 seconds of the flight it is controlled through the data link (using an AN/AWW-13 pod on the launching aircraft) using imagery from the IIR seeker.

http://www.designation-systems.net/dusrm/m-84.html
.

The purpose of flares is to deceive a missile that has already locked onto the aircraft. The newly ejected flare makes the apparent IR target seem stronger. As an angular separation develops between the flare and the target, the idea is that the missile seeker will be fooled into tracking the flare rather than the target.


so basically the missile thought that the flares is the part of the aircraft it locked on to right ? ( i thought that the seeker see 2 target and choose the hotter one )

Member for

9 years 10 months

Posts: 612

As Lukos has reminded us, the R-24T R-23 and R-24 (AA-7 'Apex') series of missiles used on MiG-23 versions equipped with the Safir radar did have LOAL capability. In the early stages of flight, they used command guidance. But most LOAL weapons rely on inertial navigation system rather than command guidance, so had to await the availability of lightweight inertial technology.

IIRC, the IR variants are LOBL, while the radar variants do not use command guidance (no air to air missiles use this but the earliest ones, unless you're referring to the mid-course updates, but these missiles have no datalink), but the lock-on is delayed till after launch to avoid interference caused by the main radar's sidelobes to the missile's seeker.

Member for

10 years 5 months

Posts: 2,014

BTW wasnt mid course update , command guider and data links are basically the same thing ? what the different between them ?

Member for

17 years 7 months

Posts: 4,951

The difference is how much one emits to steer the missile. Mid course update is meant to be stealthy. Command guidance is typically meant one way communication. Data links implies two way communications, but not always using RF energy.

IIRC, the IR variants are LOBL, while the radar variants do not use command guidance (no air to air missiles use this but the earliest ones, unless you're referring to the mid-course updates, but these missiles have no datalink), but the lock-on is delayed till after launch to avoid interference caused by the main radar's sidelobes to the missile's seeker.

Ljozic, not sure what you are trying to say. IR missiles can be launched blind, with the seeker slaved to where the radar expects the target to be. The problem is the seeker may not track the intended target. And you realize semi active and active radar homing seekers operate completely different. The missile seeker on SARH has to be locked on before launch to be effective. The seeker on ARH requires mid course updates near its apex or it will have a tiny chance of interception.

Member for

11 years 6 months

Posts: 932

I think there is a misunderstanding regarding LOAL; From what I understand, LOAL indicates some ability of missile to head towards target without acquiring lock; It maybe for HOBS firing to align target into seeker cone, or fly for some time (via datalink or lofting or just flying straight) to get target into seeker's range.

IDK about R-24T; but R-27T/TE versions are technically not LOAL; they can be fired without lock command but the aircraft itself must maneuver to align missile's seeker to the target. I am reasonably sure relatively obsolete R-40T and R-24T missiles operate in same fasion. Such implementation would be much simpler, and for BVR shots, it would be pretty effective still.

As for the original question; as flare launched, missile will see two IR dots seperating from a single source. Missile does not chose to lock onto flare or aircraft. Flare is a just as large source of IR returns, and what missile sees is its original IR source seperates into two. Missile then must use complex algorithms which compares original IR source trajectory to both IR sources to decide which is the target and which is not. IIR helps as seeker has means of identifying its target, but its not foolproof either; IR seekers have no means of reducing gain, half dozen flares launched in succession will still flood any seeker.

Member for

10 years 5 months

Posts: 2,014

The difference is how much one emits to steer the missile. Mid course update is meant to be stealthy. Command guidance is typically meant one way communication. Data links implies two way communications, but not always using RF energy.

.


wait wasn't there are 2 kind of data link 1 way and 2 way data link, also there sth called track via missile as well is it same as data link

Member for

10 years 5 months

Posts: 2,014

BTW does anyone know why all active radar guide missile can be LOAL but not the same for Ir guide missiles

Member for

10 years 6 months

Posts: 1,760

BTW does anyone know why all active radar guide missile can be LOAL but not the same for Ir guide missiles

Mainly a datalink issue. It's difficult to develop LOAL-capable technology without a datalink but the ASRAAM is an exception in that respect.

Member for

10 years 6 months

Posts: 1,760


IDK about R-24T; but R-27T/TE versions are technically not LOAL; they can be fired without lock command but the aircraft itself must maneuver to align missile's seeker to the target. I am reasonably sure relatively obsolete R-40T and R-24T missiles operate in same fasion. Such implementation would be much simpler, and for BVR shots, it would be pretty effective still.

You are correct about the R-40T/TD and it was one of the missiles that made the MiG-25 relatively successful in combat, despite facing some tough opposition. I think officially it's record stands at 8:8 KDR in air-combat but unofficially it could >30:8.

Member for

10 years 5 months

Posts: 2,014

Mainly a datalink issue. It's difficult to develop LOAL-capable technology without a datalink but the ASRAAM is an exception in that respect.

but how about this ?
AGM-65 can only be used in LOBL mode while AGM-114 can be used both in LOAL and LOBL , both kind of missile dont have data link or anything other than their main seeker

also what about agm-84 radar version vs AGM-84E ? why the agm-84E cannot lock on target by itself but required pilot control in terminal phase of flight

Member for

10 years 6 months

Posts: 1,760

but how about this ?
AGM-65 can only be used in LOBL mode while AGM-114 can be used both in LOAL and LOBL , both kind of missile dont have data link or anything other than their main seeker

I think the issue there is that most laser guided weapons will always be able to LOAL to a laser spot and MWR seekers (AGM-114L and Brimstone) also have a LOAL capability. Ground targets are also relatively slow compared to aircraft, so if you fire a missile at fairly short ranges to a GPS co-ordinate the MWR will be able to LOAL. Longer range equivalent A2G missiles like SPEAR have a datalink, because the range is such that the target vehicle may have moved considerably between launch and impact.


also what about agm-84 radar version vs AGM-84E ? why the agm-84E cannot lock on target by itself but required pilot control in terminal phase of flight

E, H and K I believe are IIR seeker variants with a datalink. I believe the ARH seeker variants lacked a data link.

Interestingly AGM-62 did have a datalink, which later ended up on the AGM-84E along with the IIR seeker of the AGM-65D.

Member for

9 years 10 months

Posts: 612

Ljozic, not sure what you are trying to say. IR missiles can be launched blind, with the seeker slaved to where the radar expects the target to be. The problem is the seeker may not track the intended target. And you realize semi active and active radar homing seekers operate completely different. The missile seeker on SARH has to be locked on before launch to be effective. The seeker on ARH requires mid course updates near its apex or it will have a tiny chance of interception.

The quoted part is the hint that the context is clearly limited to the R-23/24 family of missiles. I did in fact misuse the quoted LOAL term in my post, but from what I've read on some forums, the R-23R SARH seeker RGS-23 (maybe R-24R, too) seems to be technically locked on to the target three seconds after launch to avoid interference from the radar, albeit the seeker is turned to the direction of the target before the launch.

Regarding the IR variants, the seeker can be slaved to the radar so that the proper target is locked on, but still needs to be locked on before the launch.

Member for

9 years 10 months

Posts: 612

IDK about R-24T; but R-27T/TE versions are technically not LOAL; they can be fired without lock command but the aircraft itself must maneuver to align missile's seeker to the target. I am reasonably sure relatively obsolete R-40T and R-24T missiles operate in same fasion. Such implementation would be much simpler, and for BVR shots, it would be pretty effective still.

You're totally right about the LOAL term, but I would still like to see some proof that the mentioned IR variants were actually intended to be launched that way (i.e. without a proper lock) operationally. Yes, there is an override so that they could be launched without a proper lock, but AFAIK, it was intended for jettison purposes since these missiles are carried on rail pylons, not ejector ones, so they cannot be simply jettisoned. The sources I've seen indicate that the seeker must be locked on before launch (e.g. to be able to lock the target, it also needs to be cooled down first using the cooling liquid from the tank located in the pylon).

Member for

10 years 5 months

Posts: 2,014

I think the issue there is that most laser guided weapons will always be able to LOAL to a laser spot and MWR seekers (AGM-114L and Brimstone) also have a LOAL capability. Ground targets are also relatively slow compared to aircraft, so if you fire a missile at fairly short ranges to a GPS co-ordinate the MWR will be able to LOAL. Longer range equivalent A2G missiles like SPEAR have a datalink, because the range is such that the target vehicle may have moved considerably between launch and impact.

so why can't AGM-65 do that ? , both agm-114 and AGM-65 are air to ground , both have short range , both dont have data link why , agm-114 can do LOAL but AGM-65 must be lock on target before launch ?

E, H and K I believe are IIR seeker variants with a datalink. I believe the ARH seeker variants lacked a data link.

Interestingly AGM-62 did have a datalink, which later ended up on the AGM-84E along with the IIR seeker of the AGM-65D.


AGM-84H and AGM-84K both have Automatic Target Acquisition (ATA) so they can do LOAL and can actually lock target by them self , however iam talking about the E version
AGM-84E must be manually locked on to target by pilot , it cannot do that by it self . the question is why ?
all AGM-84 version have INS so they can all go to target area without main seeker , but while the radar version can do LOAL and can lock target by them self automatically , but for the AGM-84E IIR version , pilot must do that manually in final phase of flight .r GBU-15 have exact the same problem

Member for

17 years 7 months

Posts: 4,951

The hurdle of LOAL is being able to place a missile in an optical approach for the conical limited seeker. Missiles have oscillations, gyrations, and directional aspects to wield. Simply launching a missile on a ballistic trajectory has always been possible for US aircrews, but perhaps the Soviets used idiot proof safeguards. LOAL really involves traveling to a point in 3-dimensional space in such a way the seeker has a valid opportunity to track the target.

Member for

10 years 6 months

Posts: 1,760

so why can't AGM-65 do that ? , both agm-114 and AGM-65 are air to ground , both have short range , both dont have data link why , agm-114 can do LOAL but AGM-65 must be lock on target before launch ?

Most AGM-65s have either EO or IIR seekers. Only the C and E variants were laser guided. A laser guided weapon knows the laser code it's looking for whereas a missile with an IIR seeker doesn't know what it's looking for unless told before launch, or unless it has an extensive database of targets and target recognition software.

I'm not sure if the AGM-65s had INS, so even the C and E laser variants wouldn't know where to fly to if fired before lock. Some reading around the Maverick design suggests that they needed to maintain lock from launch to strike.

Interestingly the proposed AGM-65L "Longhorn" was intended to have a datalink and LOAL.


AGM-84H and AGM-84K both have Automatic Target Acquisition (ATA) so they can do LOAL and can actually lock target by them self , however iam talking about the E version
AGM-84E must be manually locked on to target by pilot , it cannot do that by it self . the question is why ?
all AGM-84 version have INS so they can all go to target area without main seeker , but while the radar version can do LOAL and can lock target by them self automatically , but for the AGM-84E IIR version , pilot must do that manually in final phase of flight .r GBU-15 have exact the same problem

To your first question, the answer is likely software related (see above talk about target database and target recognition). If the E version didn't have the ATA you mentioned, you've answered your own question.;) Visual IIR recognition is more complicated to program than radar signature recognition.

Member for

10 years 6 months

Posts: 1,760

The hurdle of LOAL is being able to place a missile in an optical approach for the conical limited seeker. Missiles have oscillations, gyrations, and directional aspects to wield. Simply launching a missile on a ballistic trajectory has always been possible for US aircrews, but perhaps the Soviets used idiot proof safeguards. LOAL really involves traveling to a point in 3-dimensional space in such a way the seeker has a valid opportunity to track the target.

I think the Soviet intention in stuff like Vikhr M was actually jam resistance. By placing the dependence on the missile-aircraft relationship (laser receiver faces carrier) jamming opportunities are almost completely eliminated. The downside is perhaps a small reduction in accuracy because the missile is looking behind itself, rather than at the target, and a flight profile that makes low altitude launches and firing down hills slightly more likely to result in the missile grounding out pre-target. The launch envelope is also more restrictive and it isn't FaF.