According to this press release that was published recentely, the HTC Artemis uses a GPS chip GSC3 produced by the SiRF company. A datasheet and other technical information can be found here. Key parameters (as declared by the manufacturer) are the following:

• 140-ball grid array (BGA) with a pitch of 0.65 mm
• Pb free
• 7 mm x 10 mm x 1.4 mm
• SiRFstarIII™ GSP CoreDigital and RF in a single package
• 50-MHz ARM7TDMI processor plus 1 Mb SRAM
• SiRFLoc Client A-GPS multi-standard support
• 4 Mbit flash memory
• Low Power