How do ants find the route to a food source? All each ant does is to follow the strongest pheromone (chemical) trail left by other ants. If this process is repeated frequently enough, they will find the best route through trial and error. If ants become isolated from their group, they end up running around in circles, following their own pheromone trail until they die of exhaustion. This behavior, called "swarm intelligence" describes how complex behavior can arise from a large number of individuals each following very simple rules. Bees use swarm intelligence to cluster and disperse about the hive.
Scientists have adapted this approach to develop software for robots that mimics the organized behavior of insects: using simple rules to coordinate complex behavior among many robots. The concept is that swarms of robots could work together to perform minesweeping and search and rescue missions, with very little need for human direction. For example, if one robot in a swarm makes a discovery, the rest of the swarm unites around the discovery and begins the task it was programmed to achieve. Robotic swarms might one day be used to explore the surface of Mars.
The robots in a swarm are usually outfitted with many sensors to enable them to navigate and communicate with each other. There is a leader, equipped with an antenna that emits an infrared light signal. The other robots have similar antennae and the signal spreads. This is how they "talk" to each other.
What is GPS?
The Global Positioning System (GPS) is a group of 27 satellites operating the Earth. A GPS receiver locates four or more such satellites, figures out the distance to each, and then combines this information to deduce its own location on Earth.