With two working satellites in orbit and plans to launch 10 more satellites by the end of the year if all goes well, Swiss-based Astrocast is now focusing on lowering costs on its low-power silicon for Internet of Things (IoT) devices. One of the unique features of the Astrocast constellation will be the ability to geolocate things without having to incorporate the cost and complexity of a GPS chip and antenna.
“We’re working to low the cost of our chip to under 5 euros,” said Astrocast CEO Fabien Jordan. The chip design is taking place in France with production in quantity enabling device manufacturers to incorporate the Astrocast chip into their designs.
The Astrocast satellites incorporate two features to aid in geolocation. Each satellite incorporates a set of passive laser retroreflectors for determining the location of satellites in orbit from the ground. Information from the ground measurements can be combine with a custom-built global navigation satellite system (GNSS) payload onboard the satellites themselves. The GNSS system, designed by ETH Zurich, weighs in under 100 grams and includes four u-blox single-frequency multi-GNSS receivers with two antennas and two receivers assigned per antenna. It can compare the satellite’s orbit from different GNSS systems, including the U.S. GPS system, Russia’s GLONASS, EU’s Galileo, China’s Beidou, and Japan’s QZSS.
By using and comparing locational information from different GNSS systems and the passive laser retroreflectors on board the satellite, enough data should be available for to provide centimeter-level orbit determination with ground post-processing, according to an ETH Zurich presentation.
Being able to precisely locate satellites in orbit enables Astrocast to provide geo-location of a device on the Earth’s surface by measuring signal strength of the device’s broadband signal from one or more locations, with the location calculations performed on the ground. The advantage to Astrocast’s geo-location method is devices don’t need an onboard GPS chip and separate antenna, lowering the overall cost of device tracking and requiring less power. Depending on the application, Astrocast could provide a secondary/backup method for geo-location outside of a dedicated GNSS system that may be affected by damage, antenna loss, or spoofing/jamming.