The use of single station GPS receiver bias estimation techniques in the polar cap and auroral oval regions

The problem of receiver Differential Code Biases (DCBs) in the use of GPS measurements of ionospheric Total Electron Content (TEC) has been a constant concern amongst network operators and data users since the advent of the use of GPS measurements for ionospheric monitoring. This problem is particularly notorious in highly variable ionospheric environments, where horizontal gradients stretch the limits of the assumptions made in standard bias estimation techniques.