Ground Observation

Groundwatch -
Istar in Flux

Situational awareness is widely seen as a crucial factor in enabling the 21st Century warfighter to survive and win against less well informed conventional and asymmetric threats through prior knowledge of enemy attacks and the optimum use of available pre-emptive and retaliatory strike assets. To excel in this context requires advanced technology sensors, carried on high performance platforms.
Nato’s A321-AGS ground surveillance aircraft is to employ the Transatlantic Cooperative Airborne Radar
Roy Braybrook

The Pentagon’s recently published Quadrennial Defense Review contained important decisions for America’s future Istar (Intelligence, Surveillance, Targeting And Reconnaissance) capabilities (while this article is focussed on ground observation, there are inevitable references to items also mentioned in the article on comint and elint aircraft in this issue).


U-2 vs. RQ-4

The Lockheed Martin U-2 first flew in 1955, and on current plans will be withdrawn completely from US Air Force service by FY2011, because its endurance is “only” twelve hours, and its dual-role pilot/systems operator fatigues well before that. In contrast, its replacement, the Northrop Grumman RQ-4B Global Hawk drone, can remain airborne for 30 hours, every hour as vigilant as the last.

The U-2 is also allegedly heavy on manpower, the US Air Force 9th Reconnaissance Wing of 36 aircraft requiring around 3300 personnel. Most are at the home base at Beale AFB, California, but others support three-aircraft flights at three overseas bases. Deployed operations at Osan AB in South Korea, RAF Akrotiri on Cyprus and Al Udeid AB in Qatar are now to be terminated in that sequence.

However, now powered by a 75.6-kN General Electric F118-GE-101 engine, the 18,000 kg U-2S is more survivable than the RQ-4 drone, since it flies higher and is equipped with the new BAE Systems ALQ-221 defensive electronic warfare system. The U-2 is carrier operable and its effectiveness benefits from an ability to cruise above 70 000 ft, and to carry a payload of 2500 kg. In comparison, the current 12,110-kg RQ-4A has a payload of only 900 kg, increased to 1350 kg in the case of the production 14,630 kg RQ-4B.

The principal sensors of the U-2S are a Raytheon ASARS-2A (Advanced Synthetic Aperture Radar System–2A) and a Goodrich Senior Year Electro-optical Reconnaissance System–2 (Syers-2) long-range oblique photography (lorop) camera, both housed in the nose. The U-2S has a Raytheon RAS-1R sigint system, covering both high- and low-band operations, in large underwing slipper pods. It also has a Senior Spur satellite datalink pod and the L-3 Airborne Information Transmission System, linking it to the Distributed Common Ground System (DCGS). All imagery and information generated, except for the ‘wet film’ of the Syers-2, is available on the ground in near-real time.

The Lockheed Martin U-2 has been a world leader in ground surveillance, but it is unable to compete with the latest drones in terms of endurance. It is also criticised as labour-intensive. (Lockheed Martin)

The Lockheed Martin U-2 has been a world leader in ground surveillance, but it is unable to compete with the latest drones in terms of endurance. It is also criticised as labour-intensive. (Lockheed Martin)

The current standard equipment for the Global Hawk is the Raytheon Integrated Sensor Suite, consisting of a Sar/MTI radar similar to the U-2’s Asars-2, a Kodak digital CCD camera and a third-generation thermal imager. The RQ-4 Spiral Four of 2010 will have the new Northrop Grumman/Raytheon MP-Rtip (Multi-Platform Radar Technology Insertion Program) radar with a 1.5-metre active electronically scanned array (Aesa) radar.

In 2005 the RQ-4A Global Hawk AV3 was fitted with a rudimentary sigint package to monitor Iraqi insurgent wireless communications and bomb detonation signals. The RQ-4B will have the more sophisticated Airborne Signals Intelligence Payload, including the Northrop Grumman High-Band System Production Configuration Unit.


Aerial Common Sensor

The US Army-led, supposedly ‘joint’ (Army/Navy) Aerial Common Sensor (ACS) programme had its origins in a US Army need for a low-cost ‘battlefield support’ airborne system that would supersede the US Army’s 21-tonne Bombardier RC-7B (Dash 7) Airborne Reconnaissance – Low (ARL) and the six-tonne Raytheon RC-12 Guardrail Common Sensor (King Air B200). The RC-7B has a Raytheon Hisar radar and is used to patrol the demilitarised zone between North and South Korea. The RC-12 is used for sigint duties, flights of three triangulating emitter position.

The Lockheed Martin proposal for the US Army’s Aerial Common Sensor was based on the Embraer ERJ-145, but as the requirement developed this proved too small a platform. (Lockheed Martin)

The Lockheed Martin proposal for the US Army’s Aerial Common Sensor was based on the Embraer ERJ-145, but as the requirement developed this proved too small a platform. (Lockheed Martin)

The ACS concept was broadened to also replace the US Navy’s 61-tonne Lockheed Martin EP-3E Aries II in the sigint and jamming roles. The US Army planned to acquire 38 ACS aircraft for service from 2009/2010, and the US Navy was to buy up to 19 for service from 2012.

The ACS was required to carry a Sar/MTI radar with the ability to track targets at 300 km. It was also to be equipped with an EO/IR turret and Sigint equipment. The aircraft was to have a ceiling of at least 37,000 ft. Payload was specified as six tonnes, endurance as ten hours and speed as 650 km/hr.

In August 2004 a Lockheed Martin Integrated Systems and Solutions proposal using an Embraer ERJ-145 platform – designated RC-20 – was selected by the US Army for ACS. It was chosen over a Northrop Grumman solution based on the Gulfstream 450. An $ 879 million, 66-month SDD (System Development and Demonstration) contract was awarded, with five systems to be delivered for testing from 2006. This was to lead to an Lrip (low-rate initial production) contract award for seven aircraft in FY2007, and full-rate production in FY2009.

The US Navy version of the RC-20 was to differ in having six workstations instead of four, although this was far less than the 20 to 24 workstations of the EP-3E. The Navy also wanted a flight-refuelling probe, jamming equipment and two underwing pods.

The current Northrop Grumman RQ-4A Global Hawk (right) is being replaced in production by the stretched RQ-4B (left), which will provide a 50% increase in sensor payload. (Northrop Grumman)

The current Northrop Grumman RQ-4A Global Hawk (right) is being replaced in production by the stretched RQ-4B (left), which will provide a 50% increase in sensor payload. (Northrop Grumman)

However, by June 2005 it had become clear, as the weight and electrical power requirements of the complete ACS systems emerged, that the ERJ-145 was basically too small a platform. Reports suggest that the original US Army specification had not required that all the equipment options were to be installed simultaneously.

Lockheed Martin then proposed a switch to a larger platform, which would incur additional development expenses of around $ 500 million and a two-year programme delay. In mid-September 2005 the Army instructed the company to stop work on the project.

There appear to be two possible solutions for ACS: to continue with an RC-20 based on the 22-tonne ERJ-145, used in combination with a drone mounting some of the required sensors, or to switch the complete sensor package to a much larger manned platform.

On the latter theme it is being suggested that the 33.5-tonne Gulfstream 450 (as proposed initially by Northrop Grumman) would now be too light, and that an even heavier aircraft such as the 36-tonne Embraer ERJ-170 or -190, the 41.3 tonne Gulfstream 550, the 43-tonne Bombardier Global Express or the 50-tonne Embraer 190 would be required to take the full sensor load.

Several air forces are already operating Sigint versions of the Gulfstream IV, and the Israeli Air Force is in the process of acquiring four G 550s (named Nachshon) with an IAI/Elta EL/I-3001 Sigint suite and twelve workstations.

The Israel Defence Force is acquiring four modified Gulfstream Vs (technically G550s) for Sigint duties. The first is seen arriving at Lod air base on 26 June 2005. (IAI)

The Israel Defence Force is acquiring four modified Gulfstream Vs (technically G550s) for Sigint duties. The first is seen arriving at Lod air base on 26 June 2005. (IAI)

Nato’s A321-AGS ground surveillance aircraft is to employ the Transatlantic Cooperative Airborne Radar

 

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Encouraged by the ACS hiatus, Boeing is promoting a Sigint variant of the 82.5-tonne P-8A (a modified B737-800) as a replacement for the Navy’s twelve EP-3Es. Some 14 workstations are proposed but the P-8 could accommodate up to 25 if required. This new variant would differ externally in having a ventral ‘canoe’ radome, covering a series of rotating Sigint antennas.

Employing a B737-size airframe for ACS would be in stark contrast to the original US Army idea of a low-cost ‘battlefield support’ aircraft, but it might provide the basis for a joint development with the US Air Force. The latter is planning a long-term replacement for B707-based sensor platforms: the Northrop Grumman E-8C Joint Stars (discussed later) and the Boeing RC-135 Rivet Joint intelligence-gathering aircraft.

The US Air Force has 16 RC-135s and an equal number of unidentified Sigint aircraft known as “the Air Force special platform”. The latter is presumably the outcome of tests between 1982 and 1985 with the Northrop Grumman Tacit Blue or Battle Surveillance Aircraft Experimental, a stealth aircraft with a side-looking Hughes radar.

It currently seems unlikely, with the US Army talking of recompeting the ACS programme no earlier than FY2009, that it (or its replacement) will eventuate much before 2016. The delay will probably require service life extension programmes for both the RC-12 and EP-3.


Joint Stars

The U-2 pioneered the operational use of a Sar/MTI radar, but the combination of such a radar and a multi-station airborne command and control centre came only with the US Air Force’s Northrop Grumman E-8 Joint Stars (Surveillance Target Attack Radar System). The ‘Joint’ in this case indicates that this was originally a US Army/Air Force programme, although it soon became US Air Force-only in funding terms.

This Northrop Grumman E-8C (serial 96-0042) was the ninth production aircraft; a converted Canadian Forces C-135. It bears the ‘GA’ tail code of the 116th ACW, Georgia Air National Guard. (Northrop Grumman)

This Northrop Grumman E-8C (serial 96-0042) was the ninth production aircraft; a converted Canadian Forces C-135. It bears the ‘GA’ tail code of the 116th ACW, Georgia Air National Guard. (Northrop Grumman)

The E-8 sprang to fame in the 1991 Gulf War, when two E-8A development aircraft were deployed to monitor Iraqi Army movements and search for mobile Scud launchers. It has subsequently been successfully employed over Bosnia, Kosovo, Afghanistan and Iraq.

Joint Stars is based on a pre-used Boeing 707 airframe equipped with a Northrop Grumman APY-3 radar and a cabin with 18 operator stations. The beam of the phased-array antenna, located in a ‘canoe’ under the front fuselage, is scanned mechanically in elevation and electronically in azimuth, looking to one side of the aircraft at a time.

Beginning in 1999 the Tactical Digital Information Link – J (Tadil-J, Nato designation Link 16) was added, allowing ground tracks to be passed to similarly equipped aircraft. Other upgrades have included the Improved Data Modem and Single Channel Ground and Airborne Radio System (Sincgars), making it possible for the E-8 to communicate directly with the US Army’s Sikorsky UH-60C and Boeing AH-64D. The designation E-8D was allocated to a future Joint Stars with the improved Northrop Grumman/Raytheon MP-Rtip radar (mentioned earlier in the Global Hawk context), but it currently appears that this equipment may be reserved for a newer airframe.

The E-8C has a maximum take-off weight of 152.4 tonnes and is powered by four 80-kN Pratt & Whitney JT3D-3B turbofans. In view of its shortcomings regarding cruise altitude and take-off performance, the US Air Force has accepted in principle a ‘Seven Q Seven’ team proposal to lease 93.4 kN P&W JT8D-219s. It appears that this programme will be launched with the FY2007 budget, to be finalised later this year.

The first production-standard E-8C was delivered in 1996 and the 17th and final aircraft followed in March 2005. In October 2002 responsibility for all E-8Cs was transferred from the 93rd Air Control Wing (ACW) of Air Combat Command to the 116th ACW of the Georgia Air National Guard, their base remaining at Robins AFB, Georgia. Tail codes changed accordingly from ‘WR’ to ‘GA’. The 116th is a ‘blended’ wing of ANG and active duty personnel. It is anticipated that the E-8 will remain in US Air Force service until at least 2025.


E-10

Concern over the age and performance limitations of the E-8 Joint Stars encouraged US Air Force studies of an aircraft that would initially supplement and later replace it. The resulting Multi-sensor Command and Control Aircraft (MC2A) project or E-10A has recently been driven by growing concern over cruise missile defence, and the idea that avionics advances might enable it to also replace the service’s Boeing E-3 Awacs and RC-135.

The E-10A or Multi-sensor Command and Control Aircraft (MC2A), projected as a replacement for the E-8C Joint Stars, is based on a Boeing 767-400ER airframe. (Northrop Grumman)

The E-10A or Multi-sensor Command and Control Aircraft (MC2A), projected as a replacement for the E-8C Joint Stars, is based on a Boeing 767-400ER airframe. (Northrop Grumman)

The E-10A concept was based on the Boeing 767, because it was then anticipated that the US Air Force would buy at least 100 B767-derived tankers. The B767 airframe also had the attraction of increased ground clearance, allowing the vertical dimension of the MP-Rtip antenna to be doubled to 1.2 metres.

However, a proposal for the US Air Force to field four E-10As by 2013 was estimated at over $ four billion. There has also been a swing in favour of the use of balloon-mounted radars with even larger antennas, providing significantly greater effectiveness in cruise missile defence. Leaks from the Pentagon suggest that a single MC2A demonstrator based on a B767-400ER will nonetheless be funded, with Northrop Grumman as prime contractor, but that this is unlikely to lead to full-scale development of a B767-based E-1.


Astor

Britain declined the offer of Joint Stars, basically because it did not need the large number of workstations associated with first-day-of-war airborne battle management in long-range ‘fire brigade’ deployments. Nor did Britain need the 7.3-metre antenna of the E-8, since it was more interested in Sar functions than MTI.

Airborne tests with the Raytheon dual-mode (synthetic aperture radar and ground moving target indication) sensor in the Sentinel R1 have provided outstanding imagery. (Raytheon)

Airborne tests with the Raytheon dual-mode (synthetic aperture radar and ground moving target indication) sensor in the Sentinel R1 have provided outstanding imagery. (Raytheon)

Instead the RAF developed its own Astor (Airborne Stand-Off Radar) requirement, which led to Raytheon Systems being selected in June 1999 to provide the Sentinel R1 aircraft, based on the Bombardier Global Express. The radar is a derivative of the Asars-2 employed in the U-2, and uses a 4.3-metre antenna mounted in a ventral ‘canoe’ radome. The Sentinel also has Link 16 and an L-3 Communications intelligence fusion system.

The present £ 800 million Astor contract covers development, delivery and ten years of logistic support. The programme is for five aircraft and a total of eight GCS: six tactical ground stations consisting of four 6 x 6 Steyr vehicles, plus two operational-level ground stations housed in standard 6.1-metre containers.

The intention is that the Astor will be fully interoperable with Joint Stars, Nato’s AGS (Alliance Ground Surveillance) system and Britain’s own Watchkeeper drone system. This includes the use of their GCS, should Astor’s own be temporarily unavailable.

Powered by two 65-kN Rolls-Royce BR710 turbofans, the Sentinel can operate from runways of less than 2000 metres, deploy for over 9000 km and cruise at over 45,000 ft. It has an endurance of ten hours. The cabin is configured for three workstations, although a fourth could be added.

The first ground surveillance aircraft based on a business jet is the Raytheon Sentinel R1, of which Britain’s Royal Air Force is purchasing five examples with eight ground stations. (Raytheon)

The first ground surveillance aircraft based on a business jet is the Raytheon Sentinel R1, of which Britain’s Royal Air Force is purchasing five examples with eight ground stations. (Raytheon)

The first Sentinel had its maiden flight on 26 May 2004. In the fourth quarter of 2006 the first two Sentinels will be delivered to No 5 Army Cooperation Squadron at RAF Waddington in Lincolnshire, where they will join the Royal Air Force’s E-3 Awacs aircraft and BAE Systems Sigint Nimrod R1s. The final Sentinel is due for delivery before the end of 2007. Initial operational capability with the RAF is scheduled for February 2008.


AGS

In 1998 Nato finalised its own requirement under the designation AGS – Alliance (earlier Airborne) Ground Surveillance. An AGS Project Definition Office was opened in Brussels in February 1999. In April 2004 Nato selected a proposal by the Tips (Transatlantic Industrial Partnership for Surveillance) team, which received a Euro 22 million study contract in April 2005 and is expected to sign a Euro 350 million, 30-month design and development contract by the time these words are published. The full-scale development contract is scheduled for early 2009, and the acquisition contract by mid-2010.

The Tips team includes Northrop Grumman, Eads, Thales, Galileo Avionica, General Dynamics Canada and Indra. The proposal is based on the Transatlantic Cooperative Airborne Radar (Tcar), which combines technology from the MP-Rtip and Sostar-X radars.

The Sostar-X Aesa radar, funded by France, Germany, Italy, Spain and the Netherlands, is to be tested in this modified Fokker 100, which first flew in December 2005. (Eads)

The Sostar-X Aesa radar, funded by France, Germany, Italy, Spain and the Netherlands, is to be tested in this modified Fokker 100, which first flew in December 2005. (Eads)

The Sostar-X is a European Aesa radar, which is to be flight tested in a modified Fokker 100. The antenna is three metres long, but is scaleable to suit the platform. The test aircraft first flew on 22 December 2005. Sostar is a joint venture by Dutch Space, Eads, Galileo Avionica, Indra and Thales. The programme is being funded by France, Germany, Italy, Spain and the Netherlands.

It is anticipated that for Nato service the Tcar will be carried on the EuroHawk drone and a modified Airbus A321, with 2.75- and 5.5-metre antennas respectively. The A321 will have 14 workstations and a lengthened antenna in a cylindrical fairing over the rear fuselage. Reports refer to a projected Nato fleet of three EuroHawks and two A321s.

The Tips system includes another A321 variant, designated Airborne AGS Communications Information System (A2CIS), and providing line-of-sight communications between the Tcar platforms and the ground.

The future for AGS is impossible to predict, as Nato has no money, and dependence on multi-national funding inevitably means uncertainty and programme delays. Financial support from America appears to be crucial, but may well be withheld until America has its own system to market.

  
 

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