Weapons Locating & Counter Battery Radars

Weapons Locating and Counter-Battery Radars (WL/CBRs) are primarily used by land forces to detect incoming hostile fire and predict fall-of-shot. These radars typically detect incoming artillery and mortar fire. They may also detect incoming air-to-surface and surface-to-surface missiles and ordnance along with low-flying unmanned aerial vehicles, fixed-wing aircraft and helicopters.

Historic Development of WL/CBRs

WL/CBRs were initially adopted by artillery formations. Gunners needed to detect incoming fires and predict likely targets. This not only helped warn troops and units within the predicted zone of arrival, these radars could also predict the likely position of hostile artillery systems based upon the fall-of-shot and trajectory of fire. Such information allows counter-battery fire to be directed against these emplacements.

Counter-battery radars were an outgrowth of the ground-based air surveillance radars and combat aircraft fire control radars developed during the Second World War. Legend has it that radio operators deployed close to frontlines during that conflict could detect incoming mortar fire using their sets. This may have resulted from interference caused to radio transmissions by shells moving through the air. However, wartime radar technology lacked the accuracy to detect and track targets with radar signatures as small as artillery and mortar rounds. Artillery shells typically have radar cross sections in the order of 0.01 square meters.

Detecting Incoming Artillery Fire

By the 1970s, radar technology had sufficiently advanced to detect incoming artillery fire. The advent of solid-state electronics from the 1960s were instrumental in providing the requisite accuracy. This resulted in the development of the seminal AN/TPQ-36 Firefinder weapons locating radar entering US Army service in 1982. It has since been exported widely around the world, cycled through several upgrades and remains in service. Similar developments took place in Europe and WL/CBRs remain standard equipment in land forces around the world.

The design imperative for weapons locating radar is to have sufficient accuracy to predict not only the fall of shot, but also the point of origin. At the same time, radars need to be of a size and weight to make them easy to deploy. These radars typically transmit in C-band (5.25 gigahertz/GHz to 5.925GHz), S-band (2.3GHz to 2.5GHz/2.7GHz to 3.7GHz) and X-band (8.5GHz to 10.68GHz) frequencies. This means antennas and radar subsystems can be sized to this end.

Evolution of WL/CBR Technology

The Global War on Terror launched on the wake of the 11th September 2001, Al Qaeda insurgent attacks on the United States saw an evolution of weapons locating and counter-battery fire technology. These radars were increasingly deployed independent of artillery units. They provided incoming fire warning for fixed installations like airbases, headquarters and logistics depots in the Afghan and Iraqi theater of operations.

Over the long term, the accuracy and performance of WL/CBRs will improve. Transmission frequencies will migrate towards Ku-band (13.4GHz to 14GHz/15.7GHz to 17.7GHz) frequencies and above. This will require improvements in transmission power levels ensuring that counter battery radar using these frequencies achieve similar, or better, detection ranges to today’s systems.

Cognitive Radar

The increasing adoption of cognitive radar techniques will improve performance still further. Cognitive techniques employ Artificial Intelligence (AI) and Machine Learning (ML) software. AI and ML software will continually monitor the radar’s performance and learn from the missions and environments where it is deployed. A radar will continually improve its ability to accurately recognise the behavior of varying types of ordnance. As a result, fall-of-shot and point-of-origin will continually improve.