Relevance. Known models, algorithms and technical solutions for determining the coordinates of aircraft are partially suitable for determining the location of small spacecraft, since the latter do not have their own means of determining and transmitting coordinates. This limitation does not allow continuous control of a small spacecraft and reduces its functionality. It is proposed to use the actively developing system of automatic dependent surveillance-broadcasting, installed on aircraft and allowing transmission of their coordinates, including to small spacecraft. Such aircraft are considered to be a kind of mobile reference objects in the airspace of the Earth. The study poses and solves a modified triangulation problem – determining the coordinates of a small spacecraft by the coordinates of reference moving objects (aircraft). Purpose. Development of a block diagram of a module that calculates the coordinates of a mobile spacecraft using a mathematical model for processing signals received from reference aircraft transmitting their own coordinates. Methods. Within the framework of the article, the main physical (Doppler effect) and geometric relationships of message transmission between receivers and transmitters and hardware and software solutions are considered, designed to obtain the processing of coordinates of message transmitters on board a small spacecraft. The results obtained make it possible to determine the location of the small spacecraft. The general block diagram of the coordinate determination module has a parallel organization and can be used in high-performance computing systems. On the basis of a mathematical model, an algorithm for determining the area of finding the apparatus and a block diagram of the coordinate processing module are obtained, characterized by the presence of a specialized parallel search unit. Modeling the algorithm on the reference data has shown the required accuracy in determining the area of the vehicle as a result of solving the modified problem. The obtained values of the variance of the computational domain indicate the efficiency of this approach and justify the hardware solution of the problem of determining the coordinates of a small spacecraft. Conclusion. The block diagram of the module for determining the position of the small spacecraft based on the ADS-B signals is the most compact and energetically less expensive solution than the GPS, which allows calculating the coordinates of the small spacecraft using a receiver, the consumption of the battery is only for receiving and processing data. In contrast to the presented scheme for receiving-processing and calculating the coordinates of the small spacecraft, existing similar solutions in a number of nanosatellites of the CubeSat standard are used, in addition to the processing algorithm and the receiving path, also transmitting equipment, which is many times more energy-intensive than the equipment presented in the form of a structural diagram of the position determination module ICA, in this article.