US Rapid Capabilities Office demonstrates new radar for active protection systems

The US Rapid Capabilities and Critical Technologies Office has demonstrated a new radar called the Wideband Selective Propagation radar (WiSPR), which has been designed to minimise the electronic signal of armoured vehicles using active protection systems, according to a 21st October article posted by the US Army. 

The radar was developed over five years in partnership with the MIT Lincoln Laboratory and demonstrated with the Army Test and Evaluation Command at the Aberdeen Proving Ground. The radar uses “novel frequencies and modulations” to detect incoming anti-armour rounds with a low probability to detect/low probability to intercept radar. 

The WiSPR is shown here, it has likely been developed to support future APS efforts with a lower signals emission profile. Credit: US Army.

According to US budget documentation, the radar was also required to provide communications between vehicles. It is designed to be undetectable based upon principles of physics rather than assessments of adversary signals intelligence capabilities, the budget documentation states. 

The WiSPR itself is an Active Electronically Scanned Array (AESA) radar with over 1,000 transmitting elements. It includes a specialised cooling system that directs heat away from the system. It is expected to enter a production cycle in the coming months. The programme received approximately $25 million in funding between 2022 and 2024. 

Active protection systems are fitted to armoured fighting vehicles to intercept incoming projectiles – typically they are designed to destroy anti-tank guided missiles and rocket propelled grenades before they hit the vehicle. To do this, they use a radar to detect the missile and fire an interceptor into the missile’s path. One example of this type of system is Trophy, which was developed by the Israeli company Rafael, and is used by Israel on the Merkava Mk III and IV main battle tanks, as well as Germany on the Leopard 2A7A1, the US Army on its M1A2 SEP v2 Abrams. The UK has also selected Trophy for its Challenger 3 upgrade, and Norway for its Leopard 2A8s. 

This makes Trophy the most successful active protection system on the market, however, its Elta radars may represent a risk to the platform. They constantly emit energy to detect incoming threats, and a presentation from Rheinmetall in 2020 indicated that a typical APS like Trophy could be detected from up to 400 km away by an electronic intelligence aircraft. It is worth noting that a distributed APS like the Rheinmetall StrikeShield or the Sentinel system from Artis emit at a lower power and so are likely harder to detect from a long range. It is likely that this is the challenge that the WiSPR development is designed to address.