Hey Guys, we just issued this press release today...enjoy
Desert Star Systems of California is manufacturing a small archival fish tag. It uses Earth's magnetic field to determine latitude and its solar cell is used to determine longitude. Also, the solar cell is used at the charging unit for the aerogel capacitor, No Batteries. Software is open sourced and available to customers for review and implementing their own software... A revolutionary tag.
Desert Star Systems is located in California and specializes in underwater instrumentation. They are currently developing an archival tag under a NOAA funded project, SBIR. An archival tag is an electronic device that goes on a fish. A scientist, biologist, or student attaches the archival tag to a fish and releases it into the water. The fish then swims to an unknown destination; someone catches it, finds the tag, and sends it in for a reward. Once the researcher gets the tag back, they download the daily logs of where the fish has swum. With this information they can then reconstruct the species’ migratory pattern.
Determining the latitude and longitude at any given point is typically a finicky thing. Tag manufacturers’ rely on a light sensor built into the tag to process when sunrise and sunset is. Longitude is determined by calculating noon time, which is easily done and quite reliable. The algorithm on the tag looks at the mean of the sunrise and sunset and predicts noon time. Determining latitude can be much harder because it uses the length of the day. This can become quite unreliable as you travel north. In certain situations the length of the day remains almost exactly the same, such as during Equinoxes. In addition, sometimes the length of the day is only a few hours short in the North and South poles. So, to combat these obstacles some manufacturers rely on using sea surface temperature and depth sensors on the tags. Then combining this information with light sensing into another piece of software, provides a more reliable position trace by comparing the tags’ data to actual known sea surface temperature of certain areas.
In 2007 the National Oceanic and Atmospheric Administration issued a solicitation for companies to demonstrate the feasibility of manufacturing a small, consistently reliable archival tag with innovative geolocation mechanism and variety of ocean sensors in an inert casing. In the solicitation, 8.1.3 F-E, NOAA specifically mentioned that current tags “are expensive and rather large, limited in the parameter they can collect, have restricted data storage, and pop-off attachment/release mechanisms currently limit time at liberty to less then one year.” They also stated, “Current geolocation mechanisms in subsurface ecosystems using light provide wide estimates of latitude and longitude.”
Desert Star Systems is releasing a state-of-the-art archival tag, SeaTag-GEO. It is the first no battery, solar-powered archival tag. It's also the first archival tag to use geo-magnetics for positioning. The tag uses a 3-axis magnetometer to acquire magnetic field strength data from the Earth. The total strength of the Earth's magnetic field is well characterized, and in most parts of the planet varies distinctively with latitude. Thus, SeaTag replaces length-of-day based latitude estimation with simple and reliable magnetometer readings; a method that works independently of cloud cover or water turbidity.
SeaTag-GEO relies on sun light to keep the capacitor charged. The solar cell acquires sun light for two purposes. First, it uses the sunlight to charge the 3v aerogel capacitor. Secondly, it is acquiring data for longitude estimations. The tag records the light level every four minutes through out the day. Then, after sunset, it calculates when noon time was, which is then associated with its longitude position.
The solar cell is also used in part of the communication protocol. The docking station is used to program the tag and retrieve data once returned. With the tag placed in the docking station, data is transferred to the tag via the solar cell. The tag sends its data to the docking station through RF, there is a small built-in antenna on the tag itself. Therefore, there is no external connector that can be damaged.
Finally, the "most promising" feature of Seatag is that Desert Star Systems keeps no secrets. The algorithms used to determine noon and read the magnetic field will be published on their website and in the manual. For those researchers who want to test algorithms or have a tag run a specialized program; the SeaTag line will have a developer’s kit available. The benefit is that the researcher can see exactly why the tag is accurate or inaccurate and improve on existing algorithms, or implement their own, while sharing their discoveries with the rest of the community. It allows everyone to grow as a community and not as individuals.
If you guys are interested, you can read more about the tag on our website at www.desertstar.com