Abstract
The research question concerns the correlation between Global Positioning System (GPS) error signals and geomagnetic activity in the ionosphere. The purpose of this investigation was to learn more about the correlation between GPS errors and geomagnetic activity in the ionosphere. Additionally it was to investigate the specifics of this correlation to find out exactly what values and measurements in the GPS system are affected and involved. In this project, the GPS errors were determined by WAAS (Wide Area Augmentation System).WAAS only spans over North America and is a correction system that was installed to supplement and correct the GPS in hopes of improving accuracy, availability, and precision. WAAS can be turned off and on in many GPS systems. Since measurements with WAAS are more accurate, the difference from the measurements of elevation, latitude, and longitude taken with and without WAAS is the the error signal. Geomagnetic activity can be measured by the K-index, which is on a scale of 1-9. Access to the K-index is found online on tha NOAA website in which live data is recorded every 3 hours. As the K-index gets higher, it indicates that there is more geomagnetic activity in the ionosphere. The ionosphere is also where GPS signals are transmitted, therefore, geomagnetic activity can highly affect GPS systems and cause errors. To conduct this experiment, measurements were taken twice a day. Data collection includes the elevation, longitude, and latitude measurements taken with WAAS enabled and without WAAS. Then, the error signal was calculated for each measurement by subtracting the measurement with WAAS from the measurement without WAAS; this was done separately for each elevation, longitude, and latitude. Lastly, one would go online and immediately record the K-index value, in order to obtain the amount of geomagnetic activity present at the time. It was hypothesized that as the strength of geomagnetic activity, or K-index value, increases, then the amount of GPS errors would increase as well. After the completion of the project, the hypothesis was partially supported. There is a linear correlation in GPS errors in elevation and latitude when the K-index increased from 0 to 2, however, the correlation does not continue as the K-index increases to a value of 3. The most likely explanation for this lack in trend is that the sample size when the K-index value is 3 is less than that at the K-index between 0 to 2. The lack of enough data at the K-index value of 3 may explain why the trend fails to continue. The hypothesis is not supported for longitude as there does not seem to be a correlation in the data. Further data collection can be made to understand the reasoning behind this. In conclusion, there is a positive linear correlation between geomagnetic activity in ionosphere and GPS errors in both elevation and latitude but not in longitude.