# Maritime Over the Horizon Sensor Integration:
)1 Vlatacom Institute; Belgrade 59714, Serbia; [EMAIL_ADDRESS] (Z.P. );[EMAIL_ADDRESS] (N.L. )1 Vlatacom Institute; Belgrade 59714, Serbia; [EMAIL_ADDRESS] (Z.P. );[PERSON]SS] (N.L. )1 Vlatacom Institute; Belgrade 59714, Serbia; [EMAIL_ADDRESS] (Z.P. );[EMAIL_ADDRESS] (N.L. )1 Vlatacom Institute; Belgrade 59714, Serbia; [EMAIL_ADDRESS] (Z.P. );[EMAIL_ADDRESS] (N.L. )1 Vlatacom Institute; Belgrade 59714, Serbia; [EMAIL_ADDRESS] (Z.P. );[EMAIL_ADDRESS] (N.L. )1 Vlatacom Institute; Belgrade 59714, Serbia; [EMAIL_ADDRESS] (Z.P. );[EMAIL_ADDRESS] (N.L. )1 Vlatacom Institute; Belgrade 59714, Serbia; [EMAIL_ADDRESS] (Z.P. );[PERSON]SS] (N.L. )1 Vlatacom Institute; Belgrade 59714, Serbia; [EMAIL_ADDRESS] (Z.P. );[EMAIL_ADDRESS] (N.L. )1 Vlatacom Institute; Belgrade 59714, Serbia; [EMAIL_ADDRESS] (Z.P. );[PERSON]SS] (N.L. )1 Vlatacom Institute; Belgrade 59714, Serbia; [EMAIL_ADDRESS] (Z.P. );[EMAIL_ADDRESS] (N.L. )1 Vlatacom Institute; Belgrade 59714, Serbia; [EMAIL_ADDRESS] (N.L. )1 Vlatacom Institute; Belgrade 59714, Serbia; [EMAIL_ADDRESS] (Z.P. );[EMAIL_ADDRESS] (N.L. )1 Vlatacom Institute; Belgrade 59714, Serbia; [EMAIL_ADDRESS] (N.L. )1 Vlatacom Institute; Belgrade 59714, Serbia; [EMAIL_ADDRESS] (Z.P. );[EMAIL_ADDRESS] (N.L. )1 Vlatacom Institute; Belgrade 59714, Serbia; [EMAIL_ADDRESS] (Z.P. );[EMAIL_ADDRESS] (N.L. )1 Vlatacom Institute; Belgrade 59714, Serbia; zdravko. limiting factor is the interrupted data availability, since no airplane is able to stay in the air constantly during the whole year and during all weather conditions. Meanwhile, satellites, which are orbiting around the earth, will be over the zone of interest for a limited time only. The other approach uses a network of HFSWRs [4; 5] to ensure the constant surveillance well beyond the horizon. Since the price of the HFSWR radar network is significantly lower than the combined cost of the aforementioned sensors, and because of the fact that those sensors provide limited data availability throughout the whole year, it is clear why HFSWR networks are slowly becoming the sensors of choice for maritime surveillance at OTH distances. The data obtained from the HFSWRs must be processed before they can be combined. The tracking algorithms at the single radar level are used for that purpose. There are several types of tracking algorithms, which are approved for radars [6; 7; 8]. Moreover, a radar network for over-the-horizon sea surveillance utilizes HF radars and introduces additional challenges to the tracker design [4; 5; 9; 10; 11; 12; 13]. A single radar tracking algorithm used to pre-process data for the algorithm presented in this paper is described in [13]. When individual radar targets are ready for multi radar data fusion there are several algorithms which can be used for multi-radar multi-target data fusion [14; 15; 16; 17; 18]. The algorithm described in this paper is based on an algorithm presented in [18] and represents its successor. Based on a priori tactical knowledge (the maneuverability of the vessels of interest), a simple yet effective way for the data fusion process is chosen. This data fusion process relies on the weighted minimum mean square error (MMSE) for vessel position calculations and the Thiel-San estimator for the tracking process. While the correctness of the algorithm described in [18] is demonstrated on simulated data, the correctness of the algorithm described here is demonstrated with the data obtained from the sensors working in a real operational environment, precisely the Gulf of Guinea. The used data set is collected from all the available sensors in the operational region during a one-year period. Moreover, in order to show the validity of the vessels' positions calculated by the algorithm, AIS [19; 20] data is used. AIS reliability and accuracy is not questioned in developed countries, since in those waters the behavior of the participants in marine traffic is well regulated and controlled by governmental bodies. In the Gulf of Guinea this is not the case.