The article presents the first implementation of the Signal Doppler Frequency (SDF) location method on an Unmanned Aerial Vehicle (UAV) named Autonomous System of Location radio EmmiteRs (ASLER), employing a DJI Matrice UAV as its mobile platform for the radio sensor. The system is used for position estimation, i.e., determining the location coordinates of localized radio emitters. Such functionality is the basis of radio reconnaissance, electronic warfare, or combat systems, and many radio navigation systems. The ASLER localization procedure is based on the Doppler localization method, also known as the SDF. Its distinctive feature is the use of a single moving platform for localization. In addition, the SDF allows simultaneous localization of multiple emission sources, which is an innovative distinction compared to other solutions of this class. ASLER is the first autonomous implementation of the SDF method on a flying platform. This paper illustrates the hardware and software implementation of location sensor, and results of the first empirical studies.