Embodiments of this application provide a communication method, apparatus, and system. The method includes: determining, based on area configuration information of a first cell of a network device and location information of a terminal device, a first sub-area corresponding to the terminal device, where the area configuration information indicates information about a plurality of sub-areas corresponding to the first cell, and the plurality of sub-areas include the first sub-area; and obtaining satellite ephemeris information corresponding to the first sub-area. In the foregoing solution, the sub-area is introduced, and the terminal device only needs to obtain the satellite ephemeris information corresponding to the sub-area in which the terminal device is located. This reduces an amount of satellite ephemeris information obtained by the terminal device, and therefore can reduce overheads of the terminal device.