We extend the conventional FMCW radar concept for primary radar systems to secondary radar systems. In the first setup we show how two radar devices are synchronized to each other in order to measure their 1D-distance to each other. We then present two methods to extend the system to multiple units thereby enabling the estimation of a 2D-position. Finally, we present a novel system configuration incorporating multiple receiving antennas to measure both the 1D-distance between the radar units and the angle of arrival of the radar signals. By measuring the distance and the angle of arrival the number of radar units required for 2D-positioning can be reduced significantly, thus enabling new applications.