The use of wireless network signal strength proposed to estimate the relative position between vehicles in a robot formation set. We propose a relative leader-follower model which allows us to use the reception signal strength as control variable for robot stabilization in the formation. Vehicle sensors consist of wheel speed and steering angle, the WiFi data consist of reception signal strength (RSS) and the angle of the maximal RSS with respect to the robot orientation. A nonholonomic nonlinear model vehicle is considered, due to this nonlinearities an extended Kalman filter EKF is used. Simulation and experimental results of the proposed estimation strategy are presented.