We investigate the maneuvering control of a UAVbased relay for efficient communication with mobile ground nodes. The objective of the maneuvering control is to maximize the minimum ergodic link capacity which is achieved by any ground node. We propose an efficient maneuvering control scheme of a UAV-based relay which does not require any location or direction information of ground nodes. The proposed control scheme exploits the received signal strengths (RSSs) from ground nodes but it dose not need a channel model to estimate the location of ground nodes. Therefore, the proposed control scheme significantly reduces the communication overhead and/or computational complexity while achieving similar performance, compared with that of an optimal scheme which requires the location information of ground nodes.