A model of how internal and external sensory information contribute to the firing of place cells in the rat hippocampus, and of how these cells contribute to the rat's spatial behavior, is tested on a miniature mobile robot. The experiments show that crude visual, odometric and short-range proximity information provided by sensors on the robot is sufficient to enable the formation of a robust spatial code within rectangular environments. They further show that the model of navigation can accurately return the robot to an unmarked goal location. Since the rat's perceptual systems are probably similarly crude, these results support our intuition that the model of hippocampal function is reasonable in not demanding too much of its inputs. The combined robotic and neuronal simulation can be used to make predictions regarding both electrophysiological and behavioral experiments. Finally, the model is applied to the neural basis of navigation in humans.