SEIKO ASTRON is the first GPS solar watch in the world that can quickly indicate the local time of the place where one stays anywhere in the world by getting information from GPS satellites. We have developed the second generation of ASTRON which is smaller and thinner than the first generation, while maintaining low power consumption and reception performance. Furthermore, in the second generation, we have achieved a better usability of watch operation for the regular use as well as the reasonable design and size of watch.