There is no fix for that, that's the way it was programmed at the firmware level and multi-path is a classic problem for high sensitiviy GPS systems, it seems SiRF have found ways to improve on that -> http://www.gpspassion.com/fr/articles.asp?id=175&page=9
continued : I read some of your postings on superior performance of bt359 at walking speeds on gpspassion. Those postings were dated 2007. Were there any new better gps than bt359 for walking speeds or it is still the best receiver one can have. Appreciate for a quick info so that I can zero in on one unit. I just found globalsat bt-368i on their website. How does it fare against bt359 and holux M-1200E at walking speeds?