Correction of pseudorange errors in Galileo and GLONASS caused by biases in group delay

Both Galileo E1 OS and GLONASS L1 signals require a wider pre-correlation bandwidth than GPS C/A. The GLONASS channels are uniformly spaced on a frequency division grid, and occupy some 8MHz in total, whereas Galileo E1 OS has sidebands that are separated by about 2MHz. Being wideband is an advantage because of sharper correlation peak (Galileo) and better interference rejection; however it also exposes distant spectral components of the signal to larger variations of the front-end transfer function. Group delay differences are mostly caused by the analog components like the SAW filter or the integrated analog front-end whereas magnitude can be affected by signal conditioning done in the digital domain, for example by the insertion of recursive filters aimed at interference cancellation. These impairments must be estimated and compensated. The benefits for the consumer multi-constellation receiver are an improved precision and an enriched set of potential applications, including timing.