In this paper, a sensor spacing estimation model and a new deployment geometry are proposed to evaluate the performance of an ultrasonic sensor array according to the deployment geometry. The proposed spacing estimation model is based on the probability of false detection alarms, aperture angle and sensor range. We have proposed a design technique for the elliptical deployment geometry by giving expressions for its parameters. A practical method of calibrating the ultrasonic sensors was designed to reduce the measurement errors. An experiment was carried out, and the data collected was then analyzed statistically. An evaluation of the performance of an ultrasonic sensor array with linear and circular deployment geometry with and without our method was done and then compared to our proposed deployment geometry which was combined with the proposed method. The results show that the proposed geometry combined with the proposed method performs better than the circular and linear geometry with a correlation of 0.9997, RMSE of 2.8056, MAPE of 1.3966 and standard deviation of 0.2891. These results show the importance of the choice of deployment geometries for an application.