Continuous wave (CW) millimeter-wave radars have gained the interest from industry for accurate subwavelength distance measurements. In particular, the six-port radar architecture presents advantages such as high resolution combined with low-power consumption and low-cost implementation in the millimeter-wave regime. In this effort, a new test platform based on fully automated piezo-electric nanopositioning stages that simulates moving targets in XYZ directions with centimeter range combined with nanometer resolution is described. The test platform is crucial to yield performance metrics in terms of repeatability, sensitivity and accuracy. Preliminary experimental results considering a WR15 six-port CW radar designed and realized for harsh environment operation are presented to validate the approach proposed.