Epson Combines Functionality and Design in Seiko Astron, the World's First GPS Solar Watch

Seiko Astron

In September 2012, Seiko Watch Corporation made a huge impact with its launch of the newly-developed Seiko Astron, a GPS solar watch. The new product is the first GPS solar watch in the world with the ability to determine the wearer's position and automatically adjust to the correct time.

Sold by Seiko under the Seiko brand, Epson was the company responsible for designing and developing the product. Epson set about its task by seeking to create an original product that combined both superior functionality and design.


A new product concept

Watches are precision instruments worn for lengthy periods, and manufacturers focus on functionality, convenience, comfort and design when creating new products. The new GPS solar watch, however, must also receive positioning signals from a GPS satellite orbiting 20,000 km above the Earth's surface, but for design reasons cannot include a high-capacity solar battery. Epson's design team therefore set about trying to find the correct balance between functionality and design.

Developing a new low-power GPS module and battery control IC

Epson succeeded in finding this balance by leveraging the compact, energy-saving and high-precision technologies that it has accumulated over many years. One of the issues faced by the designers is that the GPS devices commonly used in smartphones and other such products consume a considerable amount of electricity. To meet the challenge, the team created an original GPS module that consumes only 20% of the energy of regular GPS modules, and which uses the same technology as the Epson GPS running monitor currently on the market. Epson has a long history of designing semiconductors and other components that do not exist elsewhere, and took on the difficult task of developing a new reliable power source that could provide a stable and continuous supply of solar power to the GPS device and other components. For the Seiko Astron, Epson designed a lithium ion battery that would act as an internal secondary circuit capable of ensuring a constant supply of electricity at peak usage times. Another development was a new battery protection IC that controls the recharging and supply of electricity from the lithium ion battery, and another new IC that reduces energy consumption by 90%.The latter was necessary because no such IC existed that was suitable for watches.

Antenna shape the key to data reception and design

The hardest part of developing the Quartz Astron was balancing the need for a highly sensitive data reception function with the need for a classy exterior design required for such a product. Epson achieved this balance by completely redesigning the antenna that receives data from the GPS satellite.

The antenna is a difficult component because it needs to be mounted in a way to ensure it doesn't communicate with other components, and also because metal casing causes its sensitivity to decline considerably. Epson solved this by designing an original ring antenna (fig.1). The figure below shows how the Seiko Astron achieves both classy design and sensitivity to GPS signals, with a ceramic bezel used as the casing for the ring-shaped antenna. Epson's decision to incorporate the antenna into the design process from the outset resulted in a final product of superior quality.

Ring antenna structurefig.1 Ring antenna structure


The Seiko Astron is a magnificent watch that boasts a beautiful shape. Based on Epson's rich experience of designing watches, the product achieves levels of design excellence and reliability fitting of a truly groundbreaking product.