Problem with GPS satellite timing signal triggered alarms across the continent and caused an unknown number of outages, including the disruption of some features of critical infrastructure. The GPS problem was caused by an error in ground software uploaded January 26 as system operators removed space vehicle number (SVN) 23 from service. The long-planned deactivation of SVN 23, the oldest of the GPS satellites, clears the way for a new satellite, the last GPS Block IIF, which is to be launched February 4. The software problem, however, threw GPS's coordinated universal time (UTC) timing message off by 13 microseconds, which affected the timing data on legacy L-band signals and the time provided by GPS timing receivers, said 50th Space Wing spokesman James Hodges. The problem did not appear to have affected the GPS systems's ability to provide positioning and navigation service.
With an exponentially growing GNSS market, it can quickly become overwhelming when trying to decide on the ideal receiver that would meet a client's specifications. Because of this, I began collecting information on different GNSS receivers with the aim of developing a web utility that would allow the user to enter their specifications and the utility recommend suitable receivers. Over the pass couple months, I’ve been collecting publicly available information on different types of GNSS receivers.
Currently, the database consists of ~150 engineering grade GNSS receivers and information collected consider signal tracking capabilities, solution quality, data and memory, communications, physical characteristics, power and environmental conditions. The web utility is currently in an early stage of development with a few options still to be implemented and some additional data verification required.
Depending on user feedback, I am considering:
Presented is the Navstar GPS constellation status and plot maintained by the Geodetic Research Laboratory, University of New Brunswick, Canada.
Source: UNB Geodetic Research Laboratory
Motivated by one of UNAVCO's videos entitled, "Do You Call Yourself A Geodesist?" I began to wonder, am I a Geodesist?
Who is a Geodesist?
A geodesist measures the Earth's surface as well as studies the science and shape of the planet and gravitational field. Measurements are taken of the size of Earth on a global and regional scale. By taking these measurements of the Earth, crustal shifts and polar movement can be detected. Measurements can determine rate of movement and other pertinent information. A geodesist assigns 3 dimensional points on, above and below the surface of Earth to measure the average depths of oceans, mountain peaks and also abnormalities in the surface of Earth.
Different core fields of Geodesy:
Mathematical : relates to three dimensional geometrical elements of the mathematical model of the earth.
Physical : relates to the geophysical internal constitution of the earth to the corresponding gravity field and its observable effects.
Satellite : deals with satellite orbits, tracks existing satellites, and predicts the trajectory of a given missile, satellite, or spacecraft.
Astronomy : chronicles the changing position of stars and other celestial objects. Although listed separately, it overlaps other areas of geodesy and will not be pursued separately here.
Relationship with Geodesy and other fields:
Components of the flowchart were adopted from, Vanicek, Petr, and Edward J. Krakiwsky. Geodesy: the concepts. Elsevier, 2013.
It has been several weeks since I've made any substantial posts to the blog. I've been working on several projects while trying to maintain a consistent pace with the Ph. D. research. Finally, I have a complete product from one of my projects that I am able to share. Presented, is my first web based application that allows users to transform between different time systems. While the utility lacks novelty as there are other applications online with similar functionality, the focus of developing the web application was an exercise to learn R programming.