If the Philippine Army (PA) does push thru with its plan to acquire shore-based Anti-Ship Missiles (AShM),1 and if these missiles will have ranges of 150-200 km as per the RAND Corporation’s recommendation,2 then it will ALSO will needing AIRBORNE ASSETS to enable them to make use of the maximum ranges of those missiles due to the issue of RADAR HORIZON.
‘Radar Horizon Issue’
I wrote a blog about the issue of the “Radar Horizon” a couple of years ago titled, “Radar Detection and The Horizon Distance“. In summary, it basically means that since the Earth is round, it limits our ability to see objects over distance even when using radar because that object will eventually be hidden by the curved surface of the Earth. The Radar Horizon is affected by two things:
– The height of the object being observed;
– And the height of the equipment being used to observe the object.
There are actually calculators online that will help calculate this, like this page: Horizon calculator – Radar / Visual
So for example, if a radar antenna is placed at a height of 30 meters, it would be able to detect a ship whose height of most of its structure is 10 meters above the waterline at around 35 km away. In order for the antenna to “see” such a ship from further away, it will have to be put at a HIGHER elevation. This can be done by using a number of platforms, such as:
– Fixed wing aircraft
– Rotary wing aircraft (Helicopters)
– Unmanned Aerial Vehicles (UAV)
Static platforms like taller antennas or balloon-tethered platforms are not really ideal since their fixed location makes them vulnerable to enemy attack, and even if they can be mounted on mobile land platforms, the height they can be extended to is still limited, definitely lower than the altitude or height a Helicopter or aircraft can reach.
The Department of National Defense (DND) has expressed plans to acquire Maritime Patrol Aircraft (MPA) that could provide Over the Horizon targetting information for these Shore-based AShMs,3 but these will be assigned to the Philippine Air Force (PAF). I think it would be even better if the PhA itself could acquire separate assets of its own to COMPLEMENT these MPAs for the PhAF.
This will leave the long-range MPAs to patrol other areas within our territory and for use with other AShM platforms based on ships and other aircraft by the Philippine Navy and the Air Force while using shorter-ranged MPAs for use with the Shore-based AShMs. Also, more MPAs means better REDUNDANCY, if the other MPAs become unavailable due to maintenance or scheduling issues, or due to combat attrition, then the Army will still have Over-The-Horizon (OTH) targeting capability for its long-range AShMs.
Airborne assets for the Army’s Shore-based AShMs will be required to cover only areas up to 200-300 km from the shore, so a SMALLER, LIGHTER PLATFORM can be used, bringing down the cost of these aircraft as compared to the long-range requirement of the Air Force’s MPAs. And a smaller and lighter aircraft with smaller engines will also mean cheaper operating cost.
One example of a LIGHT MARITIME PATROL AIRCRAFT is the P2006T MRI which, with an empty weight of only 760 kg4 is only a tenth the weight of MPAs like the C-235 but still with a range of over a thousand kilometers. Fitted with a light but powerful radar like the Selex 5000E Surface Search Radar5 with a surface search range of around 370 km,6 it will provide pretty good support for the Army’s Shore-based AShMs.
Another option would be thru a rotary-winged platform like the AB212 Twin Huey Helicopter. This is a license-built version by Agusta Westland, and is stretched, twin-engined version of the UH-1H Helicopter7 which our Army is very familiar with. An Anti-Submarine Warfare (ASW) version is being used by the Italian Armed Forces, but fitted with a medium range Surface Search Radar like the Selex 5000E it will provide the Army a more flexible platform that could land and operate on more options than a fixed wing aircraft. The only issue then would be endurance, which will likely be shorter than that of a fixed-wing Light Patrol Aircraft like the P2006T MRI.
A third, more intriguing and exotic option would be the use of a UAV. UAVs have the advantage of being small and thus having smaller Radar Cross Sections (RCS), making them difficult to detect and shoot down from long range. Their relatively short range (limited by the range of their remote control systems) but long endurance times makes them tailor-made for operating around the shore area as a targeting system for shore-based missiles. Being even smaller than light aircraft, they provide even lower operating cost. Their disadvantage would be their higher initial cost due to the higher technological requirements. UAVs like the Heron8 and Seeker 4009 are already in use for maritime surveillance by other countries.
Aside from having a Surface Search Radar, other equipment that would be ideal to have for these aircraft are the TACTICAL DATA LINK and FORWARD LOOKING INFRA RED (FLIR). The Data Link will enable the aircraft to relay targeting information to different launchers quickly, while a FLIR sensor can act as a backup in case the radar is compromised, or if targets need to be better identified, although their shorter range will require the aircraft to move in closer to the target.
Very few details about these Shore-based AShMs have been given out to the public, no timetable as to when these will be acquired, or what their specifications will be, and one wonders if more details will be given out soon as the Armed Forces of the Philippines (AFP) have been more stingy about releasing more details of their acquisitions lately.
Long-range AShM batteries supported by airborne assets for long-range OTH detection and targeting information would be the “ideal” system right now, hopefully whatever we will be getting will be something close to these systems in order for us to be able to effectively defend our territory.
PA to get more bigger, powerful guns –DND,
Employing Land-Based Anti-Ship Missiles in the Western Pacific,
Philippines eyes Indonesian patrol aircraft,
A Light Patrol Plane for Search and Rescue And Maritime Reconnaissance,
Selex 5000E Sea Spray Multi-Mode Surveillance Radar,
Bell UH-1N Twin Huey,
IAI’s Heron UAV to make maritime patrol debut,
Seeker 400 Unmanned Aerial Vehicle Surveillance System, South Africa,