The GPS chipset in the hw6915 is made by Global Locate.
The review of the hw6915 (May 14, by Lisa Grade, Editor in Chief) said:
"While the hw6515's GPS was off to a rocky start, the hw6915 is much improved with impressive GPS sensitivity and start times ... HP doesn't tell us much about the GPS hardware, nor did they for the hw6515. It's made by Global Locate but HP doesn't state what chipset is used, whether it has SiRF and etcetera."
The chipset is in fact the GL20k (baseband) and GL-LN22 (RF) made by Global Locate (that's what Global Locate does: designs and makes GPS chips). In fact this is the identical GPS chipset used in the hw6515. The difference in performance is entirely due to a GPS software upgrade, which is also available to hw6515 users through a BIOS update on the HP website.
Why does it seem like the hw6915 has a newer, better GPS than the original hw6515? This GPS uses a host-based architecture. This means that many of the core functions usually done in a GPS chip are actually performed by GPS software running on the host CPU. Thus a software upgrade can make a significant difference in behavior of the GPS.
Frank van Diggelen
V.P. Technology, Global Locate.