The M51 uses an astro-inertial guidance system, like that of the Trident II. The M51 has a Circular Error Probe (CEP) of about 200 meters. This basically means that it will go a maximum of 200 meters away from its target. This accuracy is rather poor compared to some other equivalent Western missiles. However, the power of its warhead is sufficient that even when hitting a target 200 meters away, it will probably successfully neutralize the target
