Abstract <p>An object attitude control system suggests installing a four-input navigation receiver and a rigid frame with four antennas corresponding to each receiver input on an object. As navigation receiver measurements, high-precision, but ambiguous carrier-phase pseudoranges are used. A method is proposed for resolving integer ambiguities in the first and second carrier-phase pseudorange differences using rough a priori data on the roll, pitch, and heading (Euler angles) from inclinometers and a heading meter with a high confidence level. This method significantly reduces the initialization time, i.e., the time required to ensure the more efficient operation of the object control system as compared with the methods used previously. The simulation made has demonstrated the high efficiency of the proposed method for resolving phase ambiguities. The precision of the Euler angle estimation by the former using the second carrier-phase pseudorange differences for eight observed satellites is 0.003 rad, compared to 0.001 rad when using the first carrier-phase pseudorange differences. The proposed method ensures an attitude control system initialization time of one reading for the first carrier-phase pseudorange differences and of at least three readings for the second carrier-phase pseudorange differences. Minimization of the initialization time is crucial for dynamic objects, which indicates the priority use of the first carrier-phase pseudorange differences during the processing. Furthermore, the use of the second carrier-phase pseudorange differences leads to significant anomalous errors in the phase ambiguity resolution, which is not observed when working with the first carrier-phase pseudorange differences. However, using the first carrier-phase pseudorange differences requires careful calibration of the attitude control system’s antenna feeder path, which is quite challenging. The presented material can be used by specialists in satellite navigation, geodesy, and related disciplines.</p>