This work studies the improvement in service coverage obtained by three different approaches to combiningtwo triangulation (terrestrial and satellite) location methods for cellular networks in an urban environment.The paper assumes that the terrestrial cellular network uses enhanced observed time difference (E-OTD) in2G or observed time difference of arrival (OTDOA) in 3G, while the satellite GNSS uses the assisted globalpositioning system (A-GPS), but the analysis can be easily generalised to other triangulation methods. Astraightforward analytical model is presented to evaluate the service coverage resulting from each of thethree approaches. The model is fed with actual coverage figures, gathered from test measurements carriedout in Paris (France) for several urban scenarios. Numerical results show that the three approaches lead toimprovements in all the tested scenarios, and that the improvement obtained by the increasing complexity ofthe fusion approach depends highly on the coverage of each individual method and on the joint probabilityfunction of individual performances