The ability to relay tactical pictures to ground and air force commanders

The ability to detect, pick out and track enemy vehicular movements is a key element in achieving information superiority, especially when combined with the ability to relay tactical pictures to ground and air force commanders.

Airborne Ground Surveillance (AGS) radar has transformed the warfighting capability of the United States and the handful of other nations that have the same capability. Information superiority helps to clear what Clausewitz termed the ‘fog of war’ – and allows friendly forces to target enemy forces faster and more accurately. This can be of pivotal importance when facing massed armour in a conventional conflict with a peer or near-peer adversary. It is also a vital tool in asymmetric warfare, helping to monitor and deter enemy vehicle movements and to contribute to compiling a ‘pattern of life’ picture – a key element in combating insurgent or terrorist groups.

For full article and an AGS aircraft survey, please see MT #7/8-2018 available at FIA18, or order here.

US Navy AGS Capability

Though the US Navy has had an airborne ground surveillance capability for many years, this has always been highly classified, and relatively little is known about the programme. Some 16 P-3Cs were equipped to carry the Raytheon APS-149 Littoral Surveillance Radar System (LSRS), a wide-aperture AESA radar with GMTI capability, in a ventral canoe fairing. It is understood the system was developed in the ‘black world’ and was initially used by shadowy reconnaissance units including the Naval Air Systems Command-Flight Support Detachment at Dallas Love Field, and by VPU-1 at NAS Brunswick, for moving target detection and tracking and high resolution ground mapping at standoff ranges. The system seems to have been released to a number of P-3 ORION squadrons in late 2006, with VP-46 becoming the first such unit to begin using the LSRS pod system, operating it in the 5th and 7th Fleet theatres of operation.

It was always planned that a similar capability would be integrated on the P-8A POSEIDON – and indeed it has been said that the P-8A was based on the stretched airframe of the 737-800ER rather than the 737-700 precisely so that it could accommodate a similar canoe fairing. On the P-8A this contains the Raytheon AN/APS-154 Advanced Airborne Sensor (AAS), an evolution of the LSRS, which has been claimed to be superior to the AN/APY-7 used on J STARS, with the capability of detecting low-flying low RCS targets and of performing communications relay and EW duties. Testing of AAS on the P-8 began in 2014.

The UK and NATO

The same spectre of a massed Warsaw Pact tank assault that drove the US PAVE MOVER, SOTAS and later JSTARS programmes also prompted similar efforts in the UK. In 1980, the British Army issued its Corps Airborne Stand Off Radar (CASTOR) requirement, which called for an airborne radar with GMTI to monitor enemy movements beyond the frontline, and, in peacetime, beyond the inner-German border. This was to be carried by up to 15 TURBINE ISLANDER aircraft.

Meanwhile, the RAF evolved a requirement for a higher-flying ground surveillance SAR, intended to look at fixed targets (including bridges and airfields) at longer stand-off ranges. Nine CANBERRA PR.Mk 9s were planned to be converted to carry the new radar system.

An ISLANDER was purchased and modified as a demonstrator for the CASTOR programme, with a Ferranti MTI radar and a disc-like nose radome, while a Royal Signals and Radar Establishment (RSRE) CANBERRA was used as an ASTOR demonstrator, with a radar derived from Thorn EMI’s SEARCHWATER.

The two UK programmes were merged in 1986, with an ANDOVER testbed and a new ISLANDER (fitted with SKYMASTER radar in a bulbous spherical nose radome) joining the test programme, though the RSRE CANBERRA remained the workhorse of the Technology Demonstration Programme.

By 1991, the five year, £10.2 million TDP had proved the feasibility of using a dual mode radar that could simultaneously deliver high resolution ‘spotlights’ in SAR mode while providing wide area MTI sweeps.

Eventually, however, the UK realised that turning the TDP into a service-ready production system, with datalinks, would take years more, and opted for a more ‘off the shelf’ solution.

Though the US pushed hard for a UK purchase of JSTARS, the RAF did not need the E-8’s airborne command post capabilities and was reluctant to purchase a platform based on ageing and increasingly unsupportable Boeing 707 airframes.

Instead, the UK launched a competition for an airborne surveillance aircraft based on a bizjet platform, using an off-the-shelf, non-developmental radar.

Lockheed Martin offered a GULFSTREAM V with a Racal radar, a Texas Instruments AESA antenna and Goodyear SAR processing algorithms, to be modified by Marshall Aerospace.

Northrop Grumman made a late bid of its WIZARD system, marrying a GULFSTREAM V with JSTARS-based systems.

But it was Raytheon that was selected as the preferred bidder. Raytheon had opted for the Bombardier GLOBAL EXPRESS platform, marrying this to a derivative of the U-2R’s ASARS-2 radar, with some contribution by GEC Marconi. An initial aircraft would be converted by E-Systems at Greenville, with four more following from BAE Systems’ Broughton plant.

The USAF’s  decided to retire its primary aerial ground surveillance platform in the mid-2020s and replace it with a network of existing and new sensors linked to a ground-based command and control system. The decision announced in the Trump Administration’s budget request for Fiscal 2019 would terminate the Northrop Grumman E-8C JSTARS and cancel a three-way competition to replace the platform with a large business jet or a Boeing 737. The funding for the JSTARS recapitalisation programme will be diverted to pay for development of an advanced battle management system, but details remain scant.

For full article and an AGS aircraft survey, please see MT #7/8-2018 available at FIA18, or order here.

The line between airborne early warning and control (AEW&C) and AGS aircraft is becoming increasingly blurred, as the latest generation of advanced surveillance aircraft can genuinely offer a robust capability against both airborne and ground targets. Saab’s GlobalEye, for example, has better airborne early warning and control capabilities than previous ERIEYE aircraft, but blends this with a robust surface search and surveillance capability, including GMTI.

Some, however, believe the time for dedicated platforms may be over, with aircraft like JSTARS probably being unable to survive in a peer-level war. Large and relatively ungainly, modern airborne ground surveillance aircraft carry a high-powered, energy-emitting radar that can be detected by a hostile integrated air defence system and perhaps engaged by long range missiles.

This has led some to embrace a ‘systems-of-systems’ approach for the ground surveillance mission, under which a host of platforms (including surveillance assets like the U-2S and GLOBAL HAWK, and the sensor-rich F-35), would be linked together to perform the same basic mission as JSTARS.

Such platforms could primarily use passive sensors, but might launch small, unmanned systems carrying emitting sensors, thereby increasing the survivability of manned platforms by using deployable systems that radiate, all communicating via laser or using other low probability of intercept/low probability of detection (LPI/LPD) data links.

This would require a major shift in thinking for military authorities, who often seem to retain a rather platform-centric approach to procurement.

For full article and an AGS aircraft survey, please see MT #7/8-2018 available at FIA18, or order here.

Jon Lake is a senior aerospace expert and a regular contributor to MT.