Tavakoli, Faghihinia, and Kalhor A PC computer runs the attitude determination and control algorithms through a graphical user interface (GUI) program. The GUI component is written in C++ language. The program provides a two-way data communication with the STK software. It receives orbital parameters and sun and magnetic reference vectors in the satellite orbital position from the STK. The estimated attitude parameters are returned to the STK for the graphical simulation of the satellite attitude. The attitude determination and control loop frequency is 3 Hz. TEST RESULTS Figure 3. Algorithms framework. In this section some experimental results of an attitude maneuver using ADCS test bed are presented. The figures show the AHRS data, which illustrates the real attitude of the simulator (satellite). The estimated value in the figures illustrates the attitude parameters that are estimated from sensor measurements applying the determination algorithm. Figures 4(a)-4(d) show estimated and the measured quaternion parameters. Also Figures 5(a)-5(c) show estimated and measured Figure 4. (a) Estimated and measured q_1 in attitude maneuver. (b) Estimated and measured q_2 in attitude maneuver. (c) Estimated and measured q_3 in attitude maneuver. (d) Estimated and measured q_4 in attitude maneuver. JUNE 2017 IEEE A&E SYSTEMS MAGAZINE 19