Both the range resolution and the range ambiguity interval of a sensor system can be maintained using a very much reduced number of data carriers across the bandwidth. This is demonstrated using real data from internal sea waves collected with a multifrequency radar system. The described signal processing methods favor the use of small numbers of sensors, which, through synthesis of additional data channels, give rise to a very high signal processing gain. Large synthetic sensor arrays can be constructed using very few real sensors for applications such as phased antenna array systems, microphone arrays for seismic prospecting, or imaging multi-frequency radar systems. ¿ 1998 American Geophysical Union