The paper presents the results of a GSTP project led by GMV for ESA/ESOC to define and experimentally analyse orbit determination techniques for the cataloguing of objects in Highly Eccentric Orbits (HEO), such as the Geostationary Transfer Orbits (GTO) and Molniya-type orbits, using a combination, or fusion, of observations acquired by ground-based radars and optical telescopes. An experimental tracking campaign was scheduled and performed to test the evaluated concepts. Additionally, the needs of a future tracking network in terms of topology and sensors characteristics for the coverage of the population of HEO object were assessed and formulated. It is shown that acceptable orbit determination results for objects on eccentric orbits can only be expected when a longer arc of the orbit is covered with observations. As a result, the orbit determination of such objects would highly benefit from the combination of observations from optical telescopes and radars.