A recent upgrade in two of ESA's 15 meter ground stations, lead to the possibility to perform bi-static radar measurements to track un-cooperative targets. This paper presents the results of such a measurement campaign, in which range-rate data was recorded using ERS-2 / Envisat satellites as radar targets. By post-processing this range-rate data an orbit can be determined. The accuracy of this orbit can be evaluated by comparing it to the operational orbit. As a reference also TLE (two-line elements) data are processed and compared to the operational orbit. This shows that the orbit based on our measurement gives an improvement to the TLE based orbit in along-track and radial accuracy, yet suffering from an out-of-plane degradation.