## The First in a Series

This will be the first in a series of posts about strike systems. In modern warfare, with ubiquitous ISR—Intelligence Surveillance Reconnaissance—no assets can move freely on the surface. All manner of strike systems with sophisticated guidance can attack them with great precision. Examples include artillery (e.g., GPS-guided Excalibur shells), JDAMs and other glide bombs covered in earlier posts, cruise missiles, and ballistic missiles.

A great deal is made about the accuracy of these systems. Before launching into further posts, I thought it would be a good idea to celebrate our inner nerds and clarify objective metrics of accuracy. Why? There’s a lot of confusion out there.

Consider two simple but different statements about the Kalibr cruise missile:

1. “The Kalibr has an accuracy of 2 to 3 meters.”
2. “Baloney, the Kalibr has an accuracy of 50 meters.”

Which one is correct, and what exactly does this mean?

Both statements can be correct. Accuracy depends upon the metric and guidance system employed. The first statement is correct for the Russian military version of Kalibr, which employs GLONASS guidance. GLONASS is the Russian version of our GPS. The second statement is correct for export versions of Kalibr, which are not equipped with GLONASS guidance.

## Different Methods, Different Characteristics

There are different guidance methods, with different accuracy characteristics. Examples include GPS/GLONASS, inertial guidance, laser-guided, terrain-following, radar-guided, optically guided (remotely by a human controller), wire-guided, and on and on. The guidance technology that can be employed is bewildering, and sparks counter-technology developed to defeat it. Electronic Warfare Systems are defeating a high percentage of precision strike systems. We don’t hear about Excalibur rounds in Ukraine anymore because EWS has drastically reduced their effectiveness.

How is accuracy measured? It is a probabilistic concept. The simplest metric is the Circular Error Probable (CEP). How is this defined?

### Circular Error Probable:

“The radius of a circle, centered on the aiming point, within which 50% of strikes will occur.”