Radio interferometry is a powerful tool that can be used for a number of applications. A radio interferometer consists of a pair of directional antennas that are tuned to receive radio emissions from a source in a desired RF band. The signals from the two receivers are then cross-correlated (multiplied and accumulated) to produce a cross-correlation 'fringe pattern'. This fringe pattern can then be analyzed to produce a result ranging from an image of a distant astronomical object to the precise location of a nearby terrestrial or extra-terrestrial radio emitter.
We discuss below the images from a single dish radio telescope that has poor resolution and how the technique of radio interferometry can be used to get better resolution.