ELI5: Explain Like I'm 5

Particle filter

A particle filter is a computer algorithm that uses small pieces of information (called particles) to help track or estimate something about the world. It does this by using the particles to form an estimate of where something is (like a person or an object), what it is doing (like running or driving), or how something is changing (like the weather). The particles are like tiny pieces of information that help the computer 'picture' the world and make estimates of what it looks like. The more particles that are used, the better the estimation or tracking can be.