Looking at the expected battlespace of the near future, naval forces can expect to be forced to operate in a heavily saturated electronic warfare (EW) environment severely impacting the effectiveness of C2 systems as well as specific weapon capabilities and sensor functions in all phases of an engagement.
Disruptive EW capabilities can impact in multiple aspects of a missile engagement ranging from weapon data links, degrading the ability to provide real time target update data and control information to missile systems in flight, to weapon sensors critical to target acquisition and prosecution in the terminal phase of flight. Further, the ability to spoof or negate GPS functionality is also a significant factor affecting threat engagement and weapon accuracy at longer ranges. Therefore, against a sophisticated adversary, weapons will need to be able to operate autonomously to a large extent and be resistive to powerful EW that disables or disrupts not only target sensors but GPS and other communication channels as well.
These factors and more have influenced the development path and design choices of Saab’s RBS15 missile system in every aspect from basic hardware configuration and sensor choice to complex mission planning, targeting and engagement software architecture.
According to Miguel Svensson, Director of Business Management for the anti-ship missile system RBS15, one main reason to use an active radar target seeker is the superior ability to acquire and differentiate targets in such an environment. The active radar target seeker used in the RBS15 has a unique target discrimination capability thanks to the high resolution in both bearing and range which also contributes to discrimination and suppression of false signals from chaff, decoys and jammers. The target seeker’s functionality is software defined which allows the missile to easily adapt to new threats as they emerge and for new features to be added through software updates.
Another important aspect is the size of the target seeker area. “Since signal attenuation due to absorption by the atmosphere is much lower for radar than other wavelengths, its range is much greater than for example, an IR sensor. Thus an active radar sensor also avoids the inherent range and acquisition degradation that IR sensors face in inclement weather – something often seen in naval environments. “This allows for detection and acquisition of targets moving at high speed at long ranges, without requiring target position updates via a data link or relying on GPS positioning”, says Miguel.
The design of the RBS15 also benefits from Saab’s great experience as a world leader in radar and EW system design and production. The company’s unique knowledge of radar design provides significant insight on how to more effectively counter such technologies. Therefore, the active radar target seeker used by the RBS15 missile is powerful in order to overwhelm potential jammers. Its transmissions are also frequency agile, making it difficult for the adversary to effectively focus the jamming capability. It also incorporates other functionalities.
“RBS15 also features a special Home-On-Jam attack mode. This means that under specific circumstances and for several types of jamming, the missile can home in on the source of the interference, effectively turning it into an anti-radiation missile. This places the adversary in a difficult position; forced to either stop jamming and allow the missile to engage its preferred target, or to continue jamming and allow itself to become the target”, says Miguel Svensson.
These and several other features allow the RBS15 to counter most existing forms of active and passive electronic countermeasures and ensure that the weapon system is a powerful force multiplier to any operator.