FEINDEF 2025 – Saab present information about the Arthur (Artillery Hunting Radar) Model D development roadmap

With artillery once again at the forefront of military operations, counter-fire automatically becomes a major issue, weapon locating systems, among which radars, being key sensors to allow hitting back enemy indirect fire effectors. The shift between Saab’s Arthur C and D models is reality, the 5th Regiment Royal Artillery of the British Army being the first user of the fully digitised Arthur. But as with many other software designed systems, the development roadmap is already quite clear at the company R&D department. 

Taking the Russia-Ukraine war as the most recent example, it is clear how artillery has become once again one of the dominating arms on the battlefield. In Ukraine up to 80% of casualties is caused by indirect fire, which means artillery, mortars, and rocket systems, which can exploit drones for acquiring targets and correcting their fires. Some more numbers: Russia has been firing statistically since the war started in 2022, between 30,000 and 50,000 rounds each day, which makes approximately 10 million rounds per year. In the first two days of the war Russia fired the complete stock of artillery ammunition of the British Army, and in the two following day it would have emptied the stocks of the German Army.

Locating the source of the incoming fire is a prerequisite to be able to respond in what is known as counterbattery fire; this was true in the 1980-90 time, during the Cold War, and it has become again a key necessity in modern times. In the 1980s Saab developed a lightweight, highly mobile weapon locating system (WLS), the Arthur, which was delivered in the early 1990s, when the tension between Eastern and Western Europe had declined. That said, Saab continued to evolve its radar leveraging the advent of new technologies, the current Arthur Mod D being a far relative to the first radar delivered over 25 years ago.

Saab experts underline how much the value of a WLS is not only its sheer technical capacity, seeing the highest possible number of incoming projectiles establishing with utmost accuracy where they come from, but also its capacity to redeploy quickly, to resist to interferences from enemy electronic warfare which can also locate them as a radar is an active system, in other words a WLS needs to survive to “fight” the next battle. And surviving for such key assets, a valuable target for the enemy, is not easy task, the fact that Ukraine has lost over 100 WLS since the beginning of the war showing it very well.

To fully exploit its capabilities an agile manoeuvre concept was developed. Cuing can be done by situational need as well as by sound ranging, the latter being totally passive, while active WLS should transmit for a short period of time, then move to another location to avoid being targeted. EDR On-Line understood this requires a sort of “radar manoeuvre” involving more than one radar, ideally three of them, to maintain continuous coverage, in the same way infantry alternates fire and movement. As soon as the radar takes position, it must be adequately camouflaged, possibly with multispectral camouflage nets, as an increasing number of drones is equipped with thermal cameras. And as usual not be detected is one of the first steps in the layered protection concept. As the Arthur has a static antenna, this helps in increasing stealthness, as moving objects are much easier to see. Of course, the leapfrogging manoeuvre cannot be ongoing for days, but when things start going hot it can well be sustained for a few hours, providing critical data on enemy positions to friendly fires, allowing them to retaliate.

With mobility becoming a key feature, the radar system mass has gained importance, to allow it to be integrated on lighter vehicles.

Stepping from the Arthur Mod C, which was based on a travelling wave tube (TWT) to Mod D, which switches to active phased array technology, the antenna being made of several Gallium Nitride transmitting/receiving modules, brings the Arthur in the digital era, the system becoming in fact a software defined radar. The new Arthur benefits of digital technology also in terms of dimensions and mass, as one option a 10-foot container can host all the electronics, less constraints on power supply and cooling being a fringe benefit of the digital revolution. Some 19-inch racks are needed for the radar electronics, one more hosting customer’s communication radios. Of course, no operator is hosted in the shelter, while radar modules are accessible from outside for easy maintenance. The radar can be controlled from a laptop-based remote unit, which maintains the same human-machine interface of the system consoles.

The configuration provided to the British Army is a 12-foot container which includes operator work stations. The Arthur Mod D radars to British Army wer delivered during the first half of 2024.The British Army call them Taipan. These radars replace in Royal Artillery service the older Arthur mod B, called Mamba, delivered by Saab in 2005.

With a mass of less than 1,400 kg, without power supply and communication systems, the Arthur Mod D is vehicle agnostic and could definitely be integrated in a Boxer module or similar vehicles in the future.

Detection range of incoming projectiles differs between types. Considering Russian calibres, 300 mm rockets, such as those of the BM-30 Smerch, can be seen more than 60 km distance; 122 mm rockets and 120 mm mortar ammunition can be picked up at more than 50 km range, while 152 mm rounds can be detected at more than 30 km, all those figures referring to a detection probability of 90%, longer ranges being possible but with reduced location probability. As for accuracy a mortar tube can be located within a CEP lower than 0.15% of the distance between radar and effector, this figure increasing to 0.20% for howitzers and rocket launchers.

Saab has defined a roadmap indicating an increase in range of more than 50% mainly through software development. The roadmap also adds other capabilities, such as a power save mode, power consumption being optimised to the specific situation allowing to reduce acoustic and thermal signature and save fuel. “We know what we have to do,” a Saab expert told EDR On-Line, “we are very keen on understanding more about the requirements on the field from our customers and will adapt.”

The main challenges that Saab and other manufacturers of counter battery sensor are meeting is to take lessons learned from the war in Ukraine and implement them in the sensor fast enough.  

The former versions of the Arthur are in service with many countries. In addition to some non-disclosed customers, NATO countries such as the Czech Republic, Denmark, Greece, Italy, Sweden, Spain and the United Kingdom all have been using Arthur for many years. In Asia for example South Korea operates Arthur.

Photos Cpl R. Brown © Crown copyright 2024