Design and test implementation of a global interconnected SQUID geomagnetometer network

• Main Author: Janse van Vuuren, Lucas Jacobus
• Other Authors: Fourie, Coenrad J.
• Format: Others
• Language: en_ZA
• Published: Stellenbosch : Stellenbosch University 2015
• Subjects: Global interconnected SQUID > Design and test implementation; Geomagnetometer network; Geomagnetic field measurements; UCTD
• Online Access: http://hdl.handle.net/10019.1/96766

Thesis (MEng)--Stellenbosch University, 2015. === ENGLISH ABSTRACT: In 2012, a three-axis HTS-SQUID magnetometer project for geomagnetic measurements has been started at SANSA Space Science in Hermanus, South Africa. The goal of this project was to replicate a three-axis SQUID magnetometer for geomagnetic field measurements at LSBB at Rustrel, France. This is to allow better characterizing of faint, low frequency geomagnetic and ionospheric phenomena. To record the output signals of the SQUID magnetometers, a measurement system had to be developed. To utilise the full sensitivity of the SQUID magnetometers, the output signals have to be recorded with high accuracy. A high-speed and high-accuracy data acquisition system was installed and software was developed to record data from it. The software is capable of sending the recorded data to a web server as it is being recorded. Basic hardware control of the SQUID magnetometers has also been implemented from this data acquisition system, by monitoring conditions with its software. Timing accuracy is an important aspect of this system, in order to enable comparisons with measurements from LSBB and from different locations in the world. A GPS receiver was used to obtain the current UTC time accurately in order to timestamp measurements. A software method was devised for timestamping, to improve accuracy by triggering measurements directly from the GPS receiver. A hardware real-time clock between the GPS receiver and the rest of the system has been avoided using this method. For research purposes, this measurement data must be available on the internet for the lifetime of the system. A data server was set up and a large database of recorded data has been generated over two years of this project. Long term implementation issues have also been addressed. A web interface was developed for the data server to enable live viewing of the recorded data. This web interface also facilitates access to the raw measurements for public use. Analysis of phenomena in the recorded data has been performed by other students from Stellenbosch University. === AFRIKAANSE OPSOMMING: In 2012 is daar by SANSA Space Science in Hermanus, Suid-Afrika begin met 'n drie-as HTS-SQUID magnetometerprojek vir die opneem van geomagnetiese metings. Die doel van hierdie projek was om die drie-as SQUID magnetometer vir geomagnetiese veldmetings by LSBB naby Rustrel in Frankryk te dupliseer. Dit sou dit moontlik maak om subtiele, laefrekwensie geomagnetiese en ionosferiese verskynsels beter te beskryf. Om die uittreeseine wat deur die SQUID magnetometers voortgebring word op te neem, moes n data-opnemerstelsel ontwikkel word. Ten einde die volle sensitiwiteit van die SQUID magnetometers te benut, moes die seine baie akkuraat gemeet word. 'n Hospoed- en ho-akkuraatheidsdata-opnemer is genstalleer en die nodige sagteware is ontwikkel om hierdie data op te neem. Die sagteware is in staat om die data, soos dit opgeneem word, na 'n webbediener te stuur. Basiese hardewarebeheer van die SQUID magnetometers is ook vanaf hierdie data-opnemerstelsel gemplementeer deur toestande met die sagteware te monitor. Akkurate tydmeting is 'n belangrike aspek van hierdie sisteem, sodat metings met die van LSBB en ander soortgelyke projekte in ander posisies op die aarde vergelyk kan word. 'n GPS-ontvanger is gebruik om die UTC-tyd akkuraat te ontvang, ten einde akkurate tydstempeling by metings te voeg. 'n Sagtewaremetode vir tydstempeling is ontwikkel om akkuraatheid te bevorder deur metings direk vanaf die GPS-ontvanger te sneller. Deur hierdie metode te gebruik, is dit onnodig om n intydse hardewaretydhouer tussen die GPS-ontvanger en die res van die sisteem te gebruik. Vir navorsingsdoeleindes moet hierdie metingsdata op die internet beskikbaar wees vir die duur van die stelsel se leeftyd. 'n Databediener is opgestel en 'n baie groot databasis van opgeneemde data is oor die twee jaar van hierdie projek gegenereer. Langtermynimplementeringskwessies het ook aandag geniet. 'n Webblad is vir die databediener ontwikkel sodat die data onmiddellik besigtig kan word soos dit opgeneem word. Hierdie webblad fasiliteer ook toegang tot die rou data-opnames vir openbare gebruik. Verskynsels in die data-opnames is by SANSA geanaliseer deur ander studente van die Universiteit van Stellenbosch.