In order to combine Seiko’s solar technology with GPS, Seiko Epson spent several years conducting arduous and pioneering research and development and applied for more than 100 patents. A small GPS receiver that requires very little energy to receive GPS signals from four or more satellites was only possible thanks to Seiko's advanced energy-saving technology and Seiko's unique know-how in micro-engineering. This technology is applied to a watch with a diameter of 47mm and a weight of 135g (equipped with a high-strength titanium case and strap). Seiko Astron watches divide the world into countless "squares" and configure a time zone for each part, which is only possible with Seiko's advanced integrated circuit expertise.