UNAVCO State of NOTA Network / Southwest Regional Summary

Sean Malloy, Doerte Mann, Shawn Lawrence, Andre Basset, Karl Feaux, & Glen S. Mattioli

Published August 11, 2021, SCEC Contribution #11261, 2021 SCEC Annual Meeting Poster #096 (PDF)

The Network of the Americas (NOTA) Southwest region consists of 450 continuous GNSS/GPS stations located in Central and Southern California, Arizona, Nevada, and Mexico. 250 of these stations have full GNSS capabilities, with a mix of Trimble NetR9 and Septentrio PolaRX5 receivers. The remaining stations have Trimble NetRS receivers. UNAVCO is working to upgrade as many of these stations to full GNSS as possible with new Septentrio PolaRX5s and full spectrum GNSS antennas.

Most stations transmit data using cell modems where service is available, and most of them are already using modern 4G LTE technology. As 2G and 3G networks have limited lifetimes with defined shut off dates, we have been making an effort to remove older cell modems, with only 4 remaining modems left to upgrade due to site specific complications. We also operate several radio networks to stream data from many stations to a single cell modem or other internet access point. This provides a cost-effective alternative to cell modems and allows real-time telemetry to stations in areas without cell coverage. A small number of stations use satellite telemetry (VSAT, BGAN) or direct internet access. Most stations (407) have Real Time BINEX and Position streams available with a median latency of around 175 ms. Daily data files as well as real-time streams are available through Unavco Data Services.

At the request of the NSF, the NOTA network was downsized by 10% (128 stations) over the last year. In the Southwest region, 5 stations were removed, and 47 were transferred to other agencies for operation. There have been additional challenges in operating the network: travel and site access restrictions due to COVID-19, limiting the amount of projects we could accomplish that require multiple field personnel; a significant increase in vandalism; the increasing number and size of wildfires affecting remote stations - in the SW region, 7 stations were damaged over the last year.

Even with these challenges, the Southwest staff have completed several projects including rebuilding two enclosure support structures in the harsh environment of the Channel Islands, and rebuilding a key station in Laguna Beach, CA (THMS) that had to be removed earlier in the year due to construction

Key Words
UNAVCO, Geodesy, GNSS

Citation
Malloy, S., Mann, D., Lawrence, S., Basset, A., Feaux, K., & Mattioli, G. S. (2021, 08). UNAVCO State of NOTA Network / Southwest Regional Summary. Poster Presentation at 2021 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy