Analysis: Wishful Thinking

Forthcoming USAF platforms such as the B-21 Raider strategic bomber maybe yet more resistant to radar detection than present day low-RCS platforms (USAF)

The People’s Republic of China has made grandiose claims for the performance of its JY-27A ground-based air surveillance radar. They should be treated with caution.

An article published in the Global Times, an offshoot of the People’s Daily, itself a mouthpiece for the People’s Republic of China’s ruling Communist Party, claimed on 28 May that the country’s new CETC JY-27A Very High Frequency (VHF: 30 megahertz/MHz to 300MHz) can detect aircraft with a low Radar Cross Section (RCS). The article said that, not only can the radar detect such aircraft, but can “guide missiles to destroy them.”

Low frequency radars detecting low RCS aircraft is not a new claim. This principle has been known for decades and has already been exploited in radars like Russia’s NNIIRT 1L119 Nebo-SVU VHF system. The long wavelength signals transmitted by VHF radars have meant that while low-RCS aircraft maybe detectable, they may not be detectable with the sharp precision required to guide an Air-to-Air Missile (AAM) or Surface-to-Air Missile (SAM) to its target. Put simply, this is why many fighter radars, ground- and ship-based fire control radars and missile radar seekers transmit in frequencies from X-band (8.5 gigahertz/GHz to 10.68GHz) and above. What these radars lose in detection range, compared to lower frequency radars, they make up for in precision. The Global Times article claimed that Chinese radar engineers have solved this precision deficit by networking together several radars positioned a known distance from one another, looking at the same patch of sky in different directions to determine an aircraft’s location. Once detected it could be possible to guide “long-range anti-aircraft missiles” to perform precision strikes on these targets.

Networked Radars

Distributed, networked radars to counter stealth is an established concept. The electronic warfare and radar expert Dr. Carlo Kopp discussed this approach in his seminal 2012 article in Defence Today entitled ‘Advancing Counter-Stealth Radar Technology’. He asserted that “Defeating stealth targets using networking and data fusion presupposes that some radars can see the target some of the time, also that the target’s stealth is considerably poorer in some directions compared to others, and finally that the target is visible to radars from varying aspects.” Basically, a low RCS aircraft may have a low radar signature when viewed from head on, of from a particular angle but not an equally low signature in all directions. By scattering and networking several antennas across a wide area, one of the antennas may get a lucky glimpse of part of the aircraft which is not so stealthy and thus detect it. Dr. Kopp adds that for this to be effective, the non-stealthy part of the aircraft needs to be visible to that particular radar for some time. An aircraft flying into hostile airspace is unlikely to hang around and may be travelling at very high speeds, thus only exposing itself to the radar for a very short time. To further complicate matters, aircraft such as the US Air Force’s Northrop Grumman B-2A Spirit strategic bomber and Lockheed Martin F/A-22A Raptor air superiority fighter use ‘all-aspect’ RCS reduction techniques. This means that they are stealthy regardless of the angle from which they are viewed by radar. Future US aircraft, such as the forthcoming Northrop Grumman B-21 Raider strategic bomber are likely to have even better RCS reduction design configurations.

Dr. Kopp concedes that “a networked data fusion system (fusing data from several distributed radars) is thus not a panacea, but is potentially quite effective against stealth designs that do not have genuine ‘all aspect’ stealth capability.” There is an additional problem. Airframe limitations mean that low-RCS aircraft cannot be designed to defeat all radar transmission wavelengths. Instead, airframes are optimised to defeat the radar systems most likely to be used for the precision detection of such a target and for fire control. This typically includes radars transmitting in S-band (2.3GHz to 2.5GHz/2.7GHz to 3.7GHz) and above. To summarise, a network of VHF radars maybe capable of detecting an aircraft with a low RCS but lacking all-aspect stealth, yet weapons still have to be guided with precision to the target. This is where a fighter aircraft’s X-band radar would come into play, or the guidance radars and radar seekers used by AAMs or SAMs transmitting in X-band and above. These are precisely the frequencies that low-RCS aircraft are designed to defeat. Networked VHF radars may give you a good fix on where the aircraft is in the sky, but the missile’s end game still depends on higher frequency radars which stealth aircraft are designed to outfox.

Arguably this could be overcome by a salvo launch of SAMs and AAMs into the area of sky where the aircraft is thought to be. This might not be done with too much precision, but a load of missiles could be launched ballistically with the hope of scoring a lucky hit. It could prove an expensive tactic as it would potentially waste missiles at an early stage of a conflict, the moment when low-RCS aircraft are most likely to be used.

Jamming

Moreover, these VHF radars, and fire control radars operating in higher wavebands would almost certainly be subjected to heavy electronic attack at the outset of a conflict. Aircraft such as the F/A-22A, B-2A, B-21 or Lockheed Martin’s F-35A/B/C Lightning-II fighters would be accompanied by jamming platforms like the US Navy’s E/A-18G Growler aircraft as they fly into contested airspace. The Block-2 Low Band Jammer (LBJ) segment of the latter aircraft’s Next Generation Jammer, which replaces its current Harris AN/ALQ-99 tactical jamming system, is thought to cover a waveband of 100 megahertz to two gigahertz. The US Navy is currently selecting a vendor for the Block-2 LBJ with a team comprising Northrop Grumman and Harris, and L3 vying for selection. While VHF radars like the JY-27A maybe trying to detect low RCS aircraft, they will be a prime target for both escort and stand-off jamming for aircraft like the E/A-18G. They will also be high priority targets for kinetic weapons. Given the frequencies they use, VHF radars tend to be big. In the case of the JY-27A PRC officials have hinted that several radars are required to detect low RCS aircraft. Such targets could show up well on aerial reconnaissance imagery. They also need to transmit, and once transmitting, will reveal their position to ELINT (Electronic Intelligence) gathering assets such as the US Air Force’s Boeing RC-135U Combat Sent aircraft. Once their position is betrayed, electronic and kinetic attack can be brought to bear.

Conclusions

The PRC maybe feeling emboldened by the development of the JY-27A and its touted capabilities. The death of low RCS airframe design has been predicted umpteen times since the B-2A and Lockheed Martin F-117A Nighthawk ground attack aircraft debuted in service in 1997 and 1983 respectively. The possible shortcomings of such radars are no excuse to be complacent, and such systems should be high priority electronic and kinetic targets at the start of any conflict. The JY-27A’s attributes may be accompanied with a healthy serving of hyperbole, but that is no excuse for complacency.

Lanza Extravaganza

The UK’s acquisition of a single Indra Lanza LTR-25 deployable radar strengthens the British armed force’s operational/theatre level ground-based air defence.

The RAF’S procurement of a new Lanza LTR-25 radar will strengthen deployed, operational/theatre level ground-based air defence. (Indra)

The UK’s acquisition of a single Indra Lanza LTR-25 deployable radar strengthens the British armed force’s operational/theatre level ground-based air defence.

The UK has again strengthened its fleet of deployable radars. On 13 May Indra announced that the UK Ministry of Defence had procured a single Lanza LTR-25 L-band (1.215 gigahertz/GHz to 1.4GHz) ground-based air surveillance radar.

An official announcement from the company stated that the radar will equip the Royal Air Force (RAF) and delivery is expected by the end of the year. The radar has an instrumented range of 239 nautical miles/nm (444 kilometres/km). Although not articulated in the company’s press release the acquisition could be worth up to $13.4 million to the firm based on the derived price for this radar.The UK joins Argentina, Ecuador, Guatemala, the North Atlantic Treaty Organisation, Oman, Portugal, Rwanda, Thailand and Uruguay all of which have acquired variants of the Lanza radar over the past two decades. In British service the Lanza LTR-25 will supplement several deployable ground-based air surveillance radars. These include ten Saab Giraffe-AMB C-band (5.25GHz to 5.925GHz) ground-based air surveillance radars purchased and delivered between 2008 and 2018 jointly operated by the British Army and RAF. The Giraffe-AMB has an instrumented range of up to 54nm (100km) and is arguably configured to support short-to-medium range air defence. It is expected that  the Lanza LTR-25 will be provide surveillance to support theatre-level air defence.


Exelis’ GCA/PAR-2020 Excels

United States-based radar supplier Exelis is looking forward to a busy year regarding the company’s GCA/PAR-2020 airport surveillance and precision approach radar family with deliveries underway, and future opportunities around the world.

GCA-2020 (Exelis)
GCA-2020 (Exelis)

The company’s GCA/PAR-2020 radar family includes an array of distinct products. The GCA-2020 series includes an Airport Surveillance Radar (ASR) that can cover ranges of 30 nautical miles (56 kilometres) and altitudes of greater than 8,000 feet (2,438 metres), an L-band (1.215-1.4 gigahertz) Secondary Surveillance Radar (SSR) to receive information from aircraft transponders, and the Precision Approach Radar (PAR) that can cover ranges of 20nm (37km) with eight degrees’ elevation and 30 degrees azimuth coverage. The PAR utilizes a fully Electronically Scanning Antenna (ESA) in both azimuth and elevation significantly improving system reliability, while decreasing maintenance cost and operator workload. Both radars operate in the X-band (8.5-10.68 gigahertz).

Exelis provides these radars in fixed, mobile and transportable configurations. The baseline models of the radar family are the GCA-2000, which includes an ASR, SSR and PAR. The stand-alone PAR-2000, which provides precision approach radar services, includes an optional radar-assisted ILS (Instrument Landing System – RAILS) capability. RAILS is a unique capability allowing ILS-equipped aircraft to make precision landings without the need for traditional ILS infrastructure. The GCA-2020 and PAR-2020 are updated versions of the baseline radar which add a Mode-5/Mode-S monopulse SSR to the architecture. Mode-5/Mode-S is the latest-generation military and civilian air traffic control transponder protocol which assigns a permanent International Civil Aviation Organisation 24-bit address to each aircraft and is being rolled out across the United States as part of the Automatic Dependent Surveillance Broadcast (ADS-B) civilian air traffic management initiative. Mode-S is also being rolled out across Europe as part of Eurocontrol’s CASCADE programme. Mode-5 is the cryptographically secure version of Mode-S which enables the aircraft to also transmit its location via use of the Global Positioning System satellite constellation.

The last twelve months have been very busy for Exelis regarding its GCA/PAR-2020 family. In October 2013, Sweden ordered its second GCA-2020 deployable radar to support out-of-area operations by the Swedish armed forces such as humanitarian relief where the deployment of airfield infrastructure, such as ASR and PAR equipment maybe necessary. The company delivered its first GCA-2020 to Sweden in the 2007/8 timeframe. The country has been an enthusiastic user of this radar family and already has PAR-2000 series radars, known locally as the PAR-08, at five sites around Sweden. There is the possibility of a third GCA-2020 unit being ordered by Sweden in the near future, according to Dennis Miller, director of air traffic management, at the company.

More recently, in January 2014, Poland announced that it has purchased nine GCA-2020 systems via a Foreign Military Sale with the United States for $76mn (€56mn). Likewise, Estonia revealed in November 2013 that it would purchase a single GCA-2020 for $8mn (€5.9mn). Looking towards the future, Mr. Miller expects to receive an order from Saudi Arabia in the second quarter of this year with plans for up to three additional systems, with a country in Southern Africa also mooted as a possible customer in the 2015 timeframe.

Closer to home, Mr. Miller adds that there is the possibility of a major acquisition from the United States Department of Defense (DoD) to procure AN/FPN-68 (PAR-2020) radars to equip airbases operated by the US Army, Air Force, Navy and Marine Corps, as a replacement for the existing AN/FPN-63 Precision Approach Radar in use at several of these facilities. Finances permitting, the company hopes for the DoD to release a Request for Proposals regarding the replacement of these radars at some point this year. Exelis has deployed and installed more than 70 GCA/PAR systems worldwide in countries such as Singapore, Spain, Brazil and the United Kingdom.

Spexer Specifics

Airbus Defence and Space (formerly Cassidian) has disclosed more details regarding its latest edition to its SPEXER ground surveillance radar product line, including the new SPEXER-500’s systems architecture.

The company launched its new SPEXER-500 radar in November 2013. It is designed to perform security tasks, notably perimeter and installation protection. This X-band (8.2-12.4 Gigahertz) radar has a light weight of 34 kilograms (75 lb) making it highly portable. In terms of detection ranges, the radar provides an instrumented range of nine kilometres (six miles) and can see a pedestrian at a distance of five kilometres (three miles), a small vehicle at seven kilometres (four miles) and a large truck at nine kilometres (six miles). The SPEXER-500 can also detect air targets at a range of over four nautical miles (eight kilometres) for a light aircraft, five nautical miles (nine kilometres) for a helicopter and over one nautical mile (three kilometres) for an Unmanned Aerial Vehicle (UAV). The radar updates its imagery every 1.5 seconds when scanning a sector 120° in azimuth, whereas its scans a 30° sector in less than 0.4 seconds. The SPEXER-500 can track over 50 targets simultaneously.

In terms of architecture, the radar uses Frequency Modulated Continuous Wave (FMCW) technology. According to an Airbus Defence and Space spokesperson, this design feature facilitates: “Digital Beam Forming” (DBF) – a form of electronic scanning – that enables the SPEXER-500 to have a high Doppler resolution ensuring the reliable detection of very small and slowly moving targets such as people and UAVs, even in the presence of strong clutter.” In terms of design, the spokesperson adds that: “The radars have a very high availability and are robust in operation, certified to several international military standards. In addition, the false alarm rates are very low, even in harsh environmental conditions and in the presence of clutter.”

The SPEXER-500 is the “small brother” of the SPEXER-1000 radar which provides detection ranges of up to 36km (22 miles) also using Digital Beam Forming based on FMCW technology. For the surveillance of larger distances and coastlines, Airbus Defence and Space provides pulse Doppler radars such as the SPEXER-1500, SPEXER-2000 Coastal and SPEXER-2000 all of which use Active Electronically Scanned Array (AESA) technology.

Depeche Modes

Germany is modernising several of its MSSR-2000-I secondary radars to ensure Mode-5 compatibility
Germany is modernising several of its MSSR-2000-I secondary radars to ensure Mode-5 compatibility (Copyright – ChainHomeHigh)

European defence electronics specialist Airbus Defence and Space (formally Cassidian) has provided ChainHomeHigh with details regarding its planned modernisation of MSSR-2000-I secondary radars for the German Armed Forces.

In November 2013 the company revealed that it will upgrade these radars to so-called ‘Mode-5’ status. This programme will cover the conversion of existing MSSR-2000-Is used by the Luftwaffe (German Air Force), Deutsche Marine (German Navy) and the Heer (German Army) to Mode-5 status. Mode-5, which is employed for Identification Friend or Foe (IFF) tasks is a secure version of the International Civil Aviation Organisation’s (ICAO) 24-bit Mode-S protocol which is used to provide civilian aircraft identification and flight data information for air traffic control. All Mode-5 transmissions are encrypted and provide additional location information using the Global Positioning System satellite constellation.

Airbus Defence and Space has revealed to ChainHomeHigh that the contract to modernise these secondary radar systems which was awarded by the German Federal Office of Bundeswehr Equipment, Information Technology (known by its German acronym BAAINBw) and In-Service Support will initially cover the modernisation of 14 MSSR-2000-I systems in use onboard several German Navy ships, and in service at several airbases around the country.

A spokesperson for the firm confirmed that all of the MSSR-2000-I radars in use with the German armed forces are already Mode-5 compatible, but that the contract awarded in November 2013 will ensure their compliance with the North Atlantic Treaty Organisation’s Standardisation Agreement (STANAG) 4193. STANAG 4193 Parts 5 and 6 cover performance aspects of Mode-5. In addition, the contract also ensures compatibility with the ICAO’s Annex-10 convention on International Civil Aviation which pertains to Aeronautical Telecommunications procedures and Eurocontrol (the European body tasked with developing seamless European Air Traffic Management), European Mode S Station Functional Specification requirements. The spokesperson adds that the contract will see the modernisation of the cryptographic computers equipping the MSSR-2000-I via a software upgrade to enable them to handle Mode-5 traffic to these standards, along with legacy Mode-4 transmissions which provide a three-pulse reply to an encrypted IFF interrogation.

Airbus Defence and Space declined to provide a value for the initial contract saying that it amounted to a “multi-million Euro sum,” although the spokesperson did say that initial platform integration and acceptance will commence in 2014 and conclude in 2015, with the final deliveries of the 14 upgraded MSSR-2000-I systems being completed by 2017. Additional work for the company could include the upgrade of an additional 35 MSSR-2000-I radars operated by the German armed forces in a separate contract, alongside the modification of up to 600 Airbus defence and Space transponders used by the German Airforce to ensure that they are Mode-5 compatible. This too could be awarded in a separate contract.

The MSSR-2000-I works in tandem with Luftwaffe long-range air surveillance radars principally the air force’s four Hughes Air Defence (now Raytheon) HR-3000 S-band (2.3-2.5/2.7-3.7Ghz), its eight Lockheed Martin AN/FPS-117 400km L-band and six Thales GM-406 400-km S-band radars. All these systems feed radar information into the German Air Force’s MiRADNET radar network which supplies similar information into Germany’s civilian RADNET air traffic management network.

One of the key attractions of the MSSR-2000-I family, according to the Airbus Defence and Space, is that the entire radar is housed in a single box. This box is able to plug into any eight-metre (26-feet) antenna, with the whole system connecting to any air traffic control or integrated air defence network, using the ASTERIX radar data protocol.

In terms of performance the MSSR-2000-I family has an instrumented range of up to 613km (331nm), and can detect up to 1,500 targets across a 360º radius, 400 targets across a 45º segment of the sky and 110 targets in a 3.5º segment. Six radars comprise the MSSR-2000-I family including the MSSR-2000-I Mode 5/S 500 Watt and MSSR-2000-I Mode 5/S 1500 Watt single chain systems, the MSSR-2000-I Mode 5/S 2000 Watt variant and the MSSR-2000-I Mode 5/S 500 Watt Dual Redundant radar. This latter product includes two of the single chain 500 Watt interrogators, as does the MSSR-2000-I Mode 5/S 1500 Watt Dual Redundant radar along with the MSSR-2000-I Mode 5/S 2000 Watt Dual Redundant system which has two 2000 Watt single chain interrogators.

South Korea – New Radars On Horizon

LIG Nex-1's Long Range Air Defence Surveillance Radar (ChainHomeHigh)
LIG Nex-1’s Long Range Air Defence Surveillance Radar (ChainHomeHigh)

South Korea will commence the induction of its new LIG Nex-1 Long Range Air Defence Surveillance Radar (LRADSR) into air force service from 2015, according to company sources speaking to ChainHomeHigh at the Seoul Aerospace and Defence Exhibition held in the South Korean capital between 29th October and 3rd November.

The LRADSR is an L-band (1.215-1.4 gigahertz) system which has a range of circa 200 nautical miles (370 kilometres) and a ceiling of 100,000 feet (30,480 metres). This three-dimensional radar uses an Active Electronically Scanned Array antenna. The LRADSR is being procured to eventually replace the Lockheed Martin AN/FPS-117 L-band air surveillance radars which the Republic of Korea Air Force (ROKAF) currently uses. In terms of performance, the LRADSR has similar capabilities to the AN/FPS-117.

LIG Nex-1's Medium Range Air Defence Surveillance Radar (ChainHomeHigh)
LIG Nex-1’s Medium Range Air Defence Surveillance Radar (ChainHomeHigh)

Over the longer term, the ROKAF plans to induct LIGNex-1’s Medium Range Air Defence Surveillance Radar (MRADSR) into service which will have a shorter range of around 76nm (140km), and a 40,000ft (12,192m) ceiling. The MRADSR is an S-band (2.3-2.5/2.7-3.7ghz) radar. There is no word on when this radar may enter service nor on how many of the MRADSR and LRADSR the ROKAF may procure. As well as manufacturing the radar, LIG Nex-1 built the Identification Friend or Foe (IFF) interrogators for both systems.

These radars will join the Israel Aerospace Industries Elta Systems two EL/M-2080 Green Pine ballistic missile defence radars which have been undergoing testing in South Korea. The EL/M-2080 has a range of circa 270nm (500km), according to open source reports.

Philippines – New Radar Plans

The Philippines is continuing its upgrade and enhancement of radar air surveillance coverage across the archipelago.

On 20th September it was reported that the radar capabilities in the north of Luzon, the largest island in the Philippines would be increased. The investment into radar is intended to enhance the coverage of the West Philippine Sea, along with the wider Pacific area.

There is no word yet on what the radar acquisition will consist of in terms of radar type, number to be acquired, budget and programme timelines. However, as reported in the January 2013 edition of ChainHomeHigh, the Philippines Air Force (PAF) has announced plans to acquire three ground-based air surveillance radars.

This news follows an announcement in March 2012 that the PAF would perform a wide-ranging modernisation to include the acquisition of six combat aircraft, twelve trainers, long-range maritime patrol aircraft and a single air defence radar.

The announcement regarding the new radar (made in December 2012) now seems to indicate that the quantity of air defence radars to be purchased has been increased to three.

Little is known regarding the ground surveillance radars which the PAF currently operate, although it is thought that the force has at its disposal possibly around 20 ITT Gilfillan (now ITT Exelis) AN/TPS-32 long-range surveillance systems. Only a single system based at Wallace Air Station, a former United States Air Force facility located on Luzon Island in the northern Philippines is thought to be continually at work. This radar is believed to provide surveillance of the northern approaches to the archipelago. The AN/TPS-32 has a range of 556km (300 nautical miles) and a 100,000 feet (30,500 metre) ceiling.

Based on the performance of the AN/TPS-32 it is possible that the PAF is seeking a long-range, high-altitude radar which can be integrated into the overall Philippine Air Defence Identification Zone which is commanded by the PAF Air Defence Alert Centre, controlled by the Air Defence Wing based in PampangaProvince in the south of Luzon island.

%d bloggers like this: