Dual Microwave Radar Vehicle Detection System at Four-Quadrant-Gate Railroad Grade Crossing

This paper presents the results of a study of the detection performance of a dual microwave radar vehicle detection system installed at a railroad grade crossing with four-quadrant gates. The system included two identical microwave radar units located at opposing quadrants of the crossing. Each unit covered approximately the same detection area. The objective of the dual radar installation was to increase system reliability by providing redundancy in detection. The performance of each radar unit alone and of the two units combined was assessed in terms of false calls, missed calls, stuck-on calls, and dropped calls. The system was first evaluated on the basis of the initial setup recommended by the distributor as the best. Those results were used to modify the system, which was evaluated again in its new configuration. Twelve days of data on more than 40,000 vehicles and more than 1,300 trains were analyzed. The most frequent type of error in the initial setup was false calls (0.54%), which were generated mostly by bicycles and pedestrians in the crossing. False calls increased to 0.96% in the modified setup, mostly as a result of activations generated when the gates were moving. Individual radar outputs showed a total of 27 missed calls in the initial setup (0.07%) and 34 missed calls in the modified setup (0.09%). However, the number of missed calls dropped to zero when the outputs from the two radar units were combined, a result that illustrated the benefits of using dual units.