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Real-Time, Higher Rate NOTA GNSS Analytics and Quality Control

Session: Advances in Real-Time Geophysical Network Operations and Data Analytics [Poster]

Type: Poster

Date: 4/23/2021

Presentation Time: 03:45 PM Pacific

Description: 

The network of the America’s (NOTA) is the hemispheric geodetic facility operated by UNAVCO in support of the NSF GAGE agreement, and is the union of several pre-existing geodetic sensor networks constructed to support investigations requiring lower frequency signals and post-processed data. In addition to its original scientific goals, this network is evolving to capitalize on its primary investment to support a number of real-time, lower latency and higher frequency end users. UNAVCO is continually developing analytics to support these end users and improve overall data quality.

Currently UNAVCO provides “raw” GNSS data and precise point position (PPP) streams via NTRIPcaster in real-time with low latency (<2 seconds) from ~1140 stations. Measured end to end latencies as well as completeness as a percentage of total possible epochs are provided as daily averages. In terms of data quality, daily observational files are run through TEQC QC and postion scatter and wander plots are updated daily.

In this presentation we will share some of the ongoing efforts to better align analytics with the higher frequency, lower latency samples of the products provided. UNAVCO-NOTA is in the process of developing a new publish-subscribe model for the data streams to support a variety of scalable, distributed applications. We will present some data analytics proposed to be generated in real-time or on demand in this system, with particular emphasis on those that affect real-time/near-real time magnitude estimates such as the USGS ShakeAlert effort. Such metrics include multi-level latency measurements at the 1 second level and completeness as a function of latency, station PPP ambient noise characterizations and real-time PPP integrity. Finally, we will discuss early results of comparisons of the current server based PPP estimates with edge computing estimates generated “on-board” the GNSS receivers supported by a USGS ShakeAlert agreement.

Presenting Author: Tim Dittmann

Student Presenter: No

Authors