The purpose of this document is to describe the design and simulation of an attitude determination system (ADS) for the CubeSat Colombia I picosatellite, based on an extended Kalman filter EKF [1,2]. In this development the propagation of the State of the system has been implemented through a Runge-Kutta procedure instead of traditional State Transition matrix method, improving predictions from the EKF filter without making direct measurements of angular velocity, it was obtained a reduced prediction time by incorporating a deterministic algorithm (the TRIAD algorithm) within the EKF. The results validated through simulation are those shown in this article.