This paper examines various alternatives for the design of radio frequency-based positioning systems. In addition to the potential signals used, such settings differ in the methods employed to derive the characteristic parameter like distance or incident angle. Multiple such measurements are combined into a raw position by means of a selected positioning algorithm. Due to measurement errors, these position estimates are subject to deviations which are eliminated via a chosen tracking filter. Finally, the results of several of these systems can be merged at different levels. In addition to highlighting all these options, the paper also analyses the advantages and disadvantages of the individual alternatives and aims to provide designers of future systems with assistance in specification and implementation.