Microcalorimeters are arranged in a nm matrix, and plural element groups are composed of the microcalorimeters. A plurality of predetermined unique sequences of message types are formed and each formed sequence is allocated to one of a plurality of data sources that are used for generating user messages in the satellite-based augmentation system. The shield cover is made in one piece, making it possible to reduce the number of parts and also of the cost, and to achieve a generally compact configuration of the engine. In response to the request, the physical layer of the uplink connection is maintained while changing the downlink frequency from the first downlink frequency to the second downlink frequency. The set of rules determines autonomous generation and transmission of PSMMs by the mobile station upon detection of pilots.