TEC Measurement: Citizen Science Opportunity

Joining the Global TEC Measurement Network: Contributing to Ionospheric Research

The dual frequency radio signals of the Global Navigation Satellite System (GNSS) allow measurement of the ionosphere's Total Electron Content (TEC) along a ray path from GNSS satellite to receiver.  Space science researchers make extensive use of TEC data as a fundamental tool to probe ionospheric conditions.  TEC values are generated by post-processing data collected from worldwide networks of GNSS receivers via a non-trivial analysis suite.  One group processing GNSS data to extract TEC is the MIT Haystack Observatory (funded through a National Science Foundation facility grant).   The resulting data is stored in the Madrigal distributed database (also run by MIT Haystack).  TEC data from Haystack is being collected from roughly 5000 stations worldwide, and researchers are always interested in adding more stations to the network. 

It is not difficult to assemble a TEC monitoring station, which, in the simplest terms, consists of a purpose-built GPS receiver, external antenna and a single board computer for data collection and uploading to a cloud based server. (Note that 'GPS', or Global Positioning System, is the US version of a GNSS.  The first GPS satellite was launched in 1978.)

For more information about TEC measurements, how they are collected and used for research on topics such as large scale ionospheric disturbances, equatorial plasma bubbles, solar eclipses, ionospheric modeling and more - search on 'TEC measurements' in Google Scholar.  A few quotes from published papers appear below.

Trimble Images.001.jpeg

Assembling a TEC Measurement Station

It is not difficult to construct an Earth-based TEC measurement station, sharing data with a globally respected research institution.  Thanks to TAPR/HamSCI member John Ackermann N8UR, the task has been made fairly simple, thanks to his SBC (single board computer) programming efforts.  John collaborated with members of the MIT Haystack community to develop the code needed to reliably download, process, and then upload TEC data from a commercially available GPS unit/antenna combination.  

Hardware:

  1. Trimble NetRS GPS Reference Station (Dual band, L1/L2 GPS receiver and data logger) (DATASHEET) (USER GUIDE)
  2. GPS Antenna (SAMPLE DATASHEET)
  3. Trimble DA-26 to Ethernet/USB/Coaxial power adapter
  4. Raspberry Pi 3 or 4 SBC, monitor/keyboard/power supply/Ethernet cable
  5. Misc. items:  DC power supply, feedline between NetRS and antenna, cable adapters

Note:  All of the above is available on the 'used' market - most often on eBay.com, because the receiver components are commonly used in surveying and marine applications.  The system cost?  Approximately 250 to 350 USD.

Software & Instructions

  1. John's code is on GitHub (to find the tar.gz object code for the Raspberry Pi, open the READ.ME document, or look for the 'Releases' link on the right hand side of the GitHub page)
  2. ​Detailed instructions for configuring the Trimble NetRS and Raspberry Pi are here, on the HamSCI website

*** Special Offer *** 

Thanks to the generosity of John N8UR, a very limited number of NetRS receivers and GPS antennas are available to the citizen science community, at no charge for the hardware.  Anyone considering this offer should be prepared for the following:

The recipient...

  • ...will be responsible for shipping charges, originating from John's Ohio location
  • ...will have to obtain, at their own cost, the items noted as 4 and 5 under Hardware, above
  • ...should review the antenna placement information in the NetRS User Guide, and be able to reasonably meet the suggestions
  • ...should be comfortable with Linux command line work, as required for software installation and configuration
  • ...will have to provide an Internet connection so that the data can be uploaded to TAPR servers on a daily basis (once/day, ~0230 local time)

If you are interested, follow this link to a Google Form where we'll gather basic information (name, callsign, grid square, etc.)   Note that the selection of recipients will depend on many factors, one of which is geographic dispersion. In other words, we don't want 4 or 5 receivers located within a 50 mile radius.  The data will have more scientific value if it is obtained from locations distant from one another.  Questions?  Email hamsci@hamsci.org.

Quotable:

"Ionospheric total electron content (TEC) is one of the key parameters for users of radio-based systems, such as the Global Navigation Satellite System, high-frequency communication systems, and space-based remote sensing systems, since total ionospheric delay is proportional to TEC through the propagation path. It is important to know extreme TEC values in readiness for hazardous ionospheric conditions." (Michi Nishioka et al, Earth, Planets and Space, February, 2021)

"The availability of a large amount of TEC data derived from dual frequency GPS measurements observed by GPS reference networks provides a great opportunity for ionosphere studies." (Zhizhao Liu et al, Earth, Planets and Space, June, 2014)

"Space weather monitoring and forecast require a permanent monitoring of the ionospheric state on global scale. The world-wide use of global navigation satellite systems such as GPS and GLONASS offers the unique chance for a permanent monitoring of the total ionization (total electron content—TEC) of the global ionosphere/plasmasphere up to about 2000km height.  Ground-based GPS measurements can effectively be used for detecting large-scale horizontal structures and their motion (up to 30mS time resolution) during perturbation processes" (Geonhwa Jee et al, ​Journal of Atmospheric and Solar-Terrestrial Physics, July, 2005)
 

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Comments, questions or corrections on this web page?  Email hamsci@hamsci.org.

Version 2.0,  2025-7-10