Guided Surface to Air Missile (SAM) systems were developed during World War II but only really started to make their presence felt in the 1950s. In response, electronic counter measures (ECM)and flying tactics were developed to overcome them. This proved to be quite successful provided that reliable and timely treat warning is given to apply the counter measures and appropriate flying tactics effectively.
Analysis of aircraft losses due to enemy action since the 1960s shows that at least 70% of all losses were attributed to passive heat seekingi.e. Infra Red (IR)guided missiles. This might appear surprising considering that radar guided SAMsystems have longer engagement ranges, are faster, have higher manoeuvring potential, carries larger warheads and are equipped with proximity fuses.
The main reason why IRguided missiles were so effective was that it took much longer to develop effective warning systems against them. Most aircraft that were shot down never knew that the missile(s) were coming! Radar warning receiverson the other hand already proved their effectiveness by the early 1970s which improved the survival rate of aircraft against radar threats considerably.
The first air to air IR missiles appeared in the 1950s. The technology allowed more compact missile designs and made it possible to develop IR Man Portable Air Defence Systems (MANPADS)i.e. shoulder launched missiles, which became operational by the 1960s.
IR MANPADS are relatively cheap, quite robust, easy to operate and difficult to detect. They also do not require the infrastructure often associated with radar guided SAM deployments which is often a give away of their presence.
Vast quantities MANPADS have been manufactured (more than 700,000 produced since 1970 according to CSIS “Transnational Treats Update“ Volume 1. No 10. 2003). Large numbers proliferated during the Cold War and immediate post Cold War era. Substantial quantities are available and affordable on the black market and have found their way into the hands of “non state” organizations or the so called “asymmetric” threat. (An estimate by Jane’s Intelligence Review of Feb 2003puts this number as high as 150 000). According to an article “Proliferation of MANPADS and the Threat to Civil Aviation” of August 13, 2003 by Jane’s Terrorism and Insurgency Centre, estimates that the black market price of MANPADS could be as low as $150,000.
Intelligence regarding the whereabouts of MANPADS, especially in the hands of “non state” organizations, is usually vague and unreliable. This in turn makes it difficult to anticipate where and when to expect MANPADS attacks.
Advanced new seeker head technology, improved rocket motors and aerodynamic refinements have further increased the performance and effectiveness of MANPADS significantly as 2nd and 3rd generation MANPADS appeared by the 1980s. Their performance were improved in terms of lethal range, minimum launch angle, manoeuvring potential and all aspect engagement angles (1st generation MANPADS were restricted to only rear sector attacks). They also became more ECMresistant.
MANPADS therefore became even more lethal and specifically against more vulnerable platforms such as helicopters, light aircraft, as well as commercial and military type transport aircraft (during approaches and departures). The slower speed of these platforms forces them to spend more time within the kill zones of MANPADS compared to high performance fighter and strike aircraft.
At least 35 MANPADS attacks on civilian aircraft are on record. Twenty four were shot down killing about 500 people in the process.
Protecting aircraft against IR guided missiles depends firstly on reliable detection and warning of missiles and secondly on applying effective ECM. This discussion will mainly focus on the missile warning aspect.
Note: The above statement is not applicable to Omni Directional IR jammers which do not make use of missile warning at all as they simply radiate modulated IR energy for as long as they are switched on. Omni Directional IR jammers have been around since the 1970s and when the correct jamming modulation techniques were applied, were reasonably effective against 1st generation amplitude modulated MANPADS which operated in the near-IR band (1 to 2 micron).
The arrival of 2nd and 3rd generation MANPADS however changed all that. They operate in the mid-IR band (3 to 5 micron) and make use of more advanced modulation techniques (for example frequency modulation). Therefore instead of jamming these missiles, the Omni Directional IR jammer now actually became a source for the missiles to home in!
Providing timely warning against IR MANPADS is a big challenge. They give no warning of their presence prior to launch, they do not rely as radar and laser guided missiles do, on transmitted RF energy for guidance purposes and are also quite small in size. They are therefore not easy to detect.
MANPADS are relative short range weapons, typically up to about five kilometers with the heart of the kill envelope one to three kilometers. They therefore allow very little margin for error to effectively counter them as the time to impact (TTI) on a target at one kilometer, is only about three seconds. The TTI for targets at three and five kilometers is also relatively short – only seven and a little over eleven seconds respectively.
The MAW must therefore provide reliable and timely warning to allow appropriate counter measure responses. Near 100% probability of warning (POW) and very fast reaction times to counter nearby missile launches (in the order of one second) are therefore essential.
Air crew will only rely on the system if they have high confidence in it. The MAW must therefore also have low false alarm rates (FAR), even when engaged by multiple threats from different directions.
Quick response times and low FAR are however inherently conflicting requirements. An acceptable solution therefore requires a balanced approach to provide the most successful end result without compromising the POW.
Accurate azimuth and elevation angle of arrival (AOA) information is another very important requirement. Directional IR Counter Measures (DIRCM) systems depend on MAW systems for accurate enough initial pointing (about two degrees) to ensure that the DIRCM acquires and engages incoming missiles timely and successfully.
Accurate AOA is also important in deciding the dispensing direction of the counter measure decoys (flares). It is vital to avoid the situation where the platform and the dispensed decoys both remain within the instantaneous field of view (IFoV) of incoming missiles. Missiles could very well in situations like that, once they pass the decoys, still hit the platform! This is of particular importance where separation between the decoys and the platform takes too long as is the case with slow flying aircraft.
Accurate AOA is further important where the platform should preferably maneuver when dispensing decoys to increase the miss distance. This is however more applicable to fast jets where their high speed tends to negate the separation caused by the decoy’s ejection velocity. A turn towards approaching missiles to establish/increase the angle between the decoy and the platform is especially important in cases where a missile approaches from the rear between the five or seven ‘o clock sectors. If the AOA is not accurate enough, the pilot could very well turn in the wrong direction and set himself up for the situation as described in the previous paragraph.
The system must also be fully automated as the human reaction time in critical cases (short range launches), is too long.
Light aircraft, helicopters and fighters usually have limited space for additional equipment and are often quite sensitive to mass increases. Unavoidable mass increases should therefore be limited to prevent reductions of the platform’s payload. The system should also not cause adverse aerodynamic drag which demands that the physical size and number of boxes must be minimized. The power consumption must further be kept within the capacity of the platform’s electrical system.
To reduce the installation and integration costs, provision should also be made for the necessary interfaces to ensure proper communication and co-existence with other onboard avionics.
Integrated display and control functions are highly desirable to avoid unnecessary duplication on instrument panels where space is often severely limited. If a platform is for example equipped with both radar and missile warning systems, the HMI should be integrated to display the respective threats clearly and unambiguously.
The integrated HMI must also indicate the system’s operating status, serviceability status, mode of operation, remaining decoy quantities etc. Separate control panels are only justified for safety of flight purposes such as ECM on/off and decoy jettison functions.
Procuring EW self protection systems has direct and indirect cost implications.
Direct costs involve the initial price of the system, spare parts as well as test equipment to ensure that the performance and availability of the systems is maintained throughout their entire life cycle.
Installing and integrating EW systems on aircraft is another direct cost
Indirect cost on the other hand involves degradation of the aircraft’s performance as a result of having the system onboard which in turn impacts negatively on the operating cost of the aircraft.
The lowest initial price of a system does therefore not necessary offer the best solution as all the factors needs to be considered. The overall cost effectiveness of systems i.e. price versus performance is more important in deciding which system to select.
Three different technologies have been used for MAW systems i.e.
based systems. Each technology has their advantages and shortcomings which can be summarized as follows:
Advantages
Disadvantages
Advantages
Disadvantages
Advantages
Disadvantages
Current available MAW systems as well as those under development, represent all three types of technologies. Each technology has strong and weak points and none provide a perfect solution.
France
Israel
Japan
Russia
UK
UK and Italy
USA
Israel
France
Germany
Germany and France
UK
USA
USA and Israel
Germany
Israel
Sweden/South Africa
USA
REFERENCES
Infrared Homing (Passive Missile Guidance System)
Directional Infrared Counter Measures
Guided Surface to Air Missile (SAM) systems were developed during World War II but only really started to make their presence felt in the 1950s. In response, electronic counter measures (ECM)and flying tactics were developed to overcome them. This proved to be quite successful provided that reliable and timely treat warning is given to apply the counter measures and appropriate flying tactics effectively.
Analysis of aircraft losses due to enemy action since the 1960s shows that at least 70% of all losses were attributed to passive heat seekingi.e. Infra Red (IR)guided missiles. This might appear surprising considering that radar guided SAMsystems have longer engagement ranges, are faster, have higher manoeuvring potential, carries larger warheads and are equipped with proximity fuses.
The main reason why IRguided missiles were so effective was that it took much longer to develop effective warning systems against them. Most aircraft that were shot down never knew that the missile(s) were coming! Radar warning receiverson the other hand already proved their effectiveness by the early 1970s which improved the survival rate of aircraft against radar threats considerably.
The first air to air IR missiles appeared in the 1950s. The technology allowed more compact missile designs and made it possible to develop IR Man Portable Air Defence Systems (MANPADS)i.e. shoulder launched missiles, which became operational by the 1960s.
IR MANPADS are relatively cheap, quite robust, easy to operate and difficult to detect. They also do not require the infrastructure often associated with radar guided SAM deployments which is often a give away of their presence.
Vast quantities MANPADS have been manufactured (more than 700,000 produced since 1970 according to CSIS “Transnational Treats Update“ Volume 1. No 10. 2003). Large numbers proliferated during the Cold War and immediate post Cold War era. Substantial quantities are available and affordable on the black market and have found their way into the hands of “non state” organizations or the so called “asymmetric” threat. (An estimate by Jane’s Intelligence Review of Feb 2003puts this number as high as 150 000). According to an article “Proliferation of MANPADS and the Threat to Civil Aviation” of August 13, 2003 by Jane’s Terrorism and Insurgency Centre, estimates that the black market price of MANPADS could be as low as $150,000.
Intelligence regarding the whereabouts of MANPADS, especially in the hands of “non state” organizations, is usually vague and unreliable. This in turn makes it difficult to anticipate where and when to expect MANPADS attacks.
Advanced new seeker head technology, improved rocket motors and aerodynamic refinements have further increased the performance and effectiveness of MANPADS significantly as 2nd and 3rd generation MANPADS appeared by the 1980s. Their performance were improved in terms of lethal range, minimum launch angle, manoeuvring potential and all aspect engagement angles (1st generation MANPADS were restricted to only rear sector attacks). They also became more ECMresistant.
MANPADS therefore became even more lethal and specifically against more vulnerable platforms such as helicopters, light aircraft, as well as commercial and military type transport aircraft (during approaches and departures). The slower speed of these platforms forces them to spend more time within the kill zones of MANPADS compared to high performance fighter and strike aircraft.
At least 35 MANPADS attacks on civilian aircraft are on record. Twenty four were shot down killing about 500 people in the process.
Protecting aircraft against IR guided missiles depends firstly on reliable detection and warning of missiles and secondly on applying effective ECM. This discussion will mainly focus on the missile warning aspect.
Note: The above statement is not applicable to Omni Directional IR jammers which do not make use of missile warning at all as they simply radiate modulated IR energy for as long as they are switched on. Omni Directional IR jammers have been around since the 1970s and when the correct jamming modulation techniques were applied, were reasonably effective against 1st generation amplitude modulated MANPADS which operated in the near-IR band (1 to 2 micron).
The arrival of 2nd and 3rd generation MANPADS however changed all that. They operate in the mid-IR band (3 to 5 micron) and make use of more advanced modulation techniques (for example frequency modulation). Therefore instead of jamming these missiles, the Omni Directional IR jammer now actually became a source for the missiles to home in!
Providing timely warning against IR MANPADS is a big challenge. They give no warning of their presence prior to launch, they do not rely as radar and laser guided missiles do, on transmitted RF energy for guidance purposes and are also quite small in size. They are therefore not easy to detect.
MANPADS are relative short range weapons, typically up to about five kilometers with the heart of the kill envelope one to three kilometers. They therefore allow very little margin for error to effectively counter them as the time to impact (TTI) on a target at one kilometer, is only about three seconds. The TTI for targets at three and five kilometers is also relatively short – only seven and a little over eleven seconds respectively.
The MAW must therefore provide reliable and timely warning to allow appropriate counter measure responses. Near 100% probability of warning (POW) and very fast reaction times to counter nearby missile launches (in the order of one second) are therefore essential.
Air crew will only rely on the system if they have high confidence in it. The MAW must therefore also have low false alarm rates (FAR), even when engaged by multiple threats from different directions.
Quick response times and low FAR are however inherently conflicting requirements. An acceptable solution therefore requires a balanced approach to provide the most successful end result without compromising the POW.
Accurate azimuth and elevation angle of arrival (AOA) information is another very important requirement. Directional IR Counter Measures (DIRCM) systems depend on MAW systems for accurate enough initial pointing (about two degrees) to ensure that the DIRCM acquires and engages incoming missiles timely and successfully.
Accurate AOA is also important in deciding the dispensing direction of the counter measure decoys (flares). It is vital to avoid the situation where the platform and the dispensed decoys both remain within the instantaneous field of view (IFoV) of incoming missiles. Missiles could very well in situations like that, once they pass the decoys, still hit the platform! This is of particular importance where separation between the decoys and the platform takes too long as is the case with slow flying aircraft.
Accurate AOA is further important where the platform should preferably maneuver when dispensing decoys to increase the miss distance. This is however more applicable to fast jets where their high speed tends to negate the separation caused by the decoy’s ejection velocity. A turn towards approaching missiles to establish/increase the angle between the decoy and the platform is especially important in cases where a missile approaches from the rear between the five or seven ‘o clock sectors. If the AOA is not accurate enough, the pilot could very well turn in the wrong direction and set himself up for the situation as described in the previous paragraph.
The system must also be fully automated as the human reaction time in critical cases (short range launches), is too long.
Light aircraft, helicopters and fighters usually have limited space for additional equipment and are often quite sensitive to mass increases. Unavoidable mass increases should therefore be limited to prevent reductions of the platform’s payload. The system should also not cause adverse aerodynamic drag which demands that the physical size and number of boxes must be minimized. The power consumption must further be kept within the capacity of the platform’s electrical system.
To reduce the installation and integration costs, provision should also be made for the necessary interfaces to ensure proper communication and co-existence with other onboard avionics.
Integrated display and control functions are highly desirable to avoid unnecessary duplication on instrument panels where space is often severely limited. If a platform is for example equipped with both radar and missile warning systems, the HMI should be integrated to display the respective threats clearly and unambiguously.
The integrated HMI must also indicate the system’s operating status, serviceability status, mode of operation, remaining decoy quantities etc. Separate control panels are only justified for safety of flight purposes such as ECM on/off and decoy jettison functions.
Procuring EW self protection systems has direct and indirect cost implications.
Direct costs involve the initial price of the system, spare parts as well as test equipment to ensure that the performance and availability of the systems is maintained throughout their entire life cycle.
Installing and integrating EW systems on aircraft is another direct cost
Indirect cost on the other hand involves degradation of the aircraft’s performance as a result of having the system onboard which in turn impacts negatively on the operating cost of the aircraft.
The lowest initial price of a system does therefore not necessary offer the best solution as all the factors needs to be considered. The overall cost effectiveness of systems i.e. price versus performance is more important in deciding which system to select.
Three different technologies have been used for MAW systems i.e.
based systems. Each technology has their advantages and shortcomings which can be summarized as follows:
Advantages
Disadvantages
Advantages
Disadvantages
Advantages
Disadvantages
Current available MAW systems as well as those under development, represent all three types of technologies. Each technology has strong and weak points and none provide a perfect solution.
France
Israel
Japan
Russia
UK
UK and Italy
USA
Israel
France
Germany
Germany and France
UK
USA
USA and Israel
Germany
Israel
Sweden/South Africa
USA
REFERENCES
Infrared Homing (Passive Missile Guidance System)
Directional Infrared Counter Measures