Using GPS on robots that will operate indoors has been a problem due to the difficulties of receiving weak GPS signals. Atmel and U-Bloc have addressed this problem with a specially designed GPS engine that Atmel calls the ANTARIS. When combined with special firmware developed by U-Bloc called SuperSense, the resulting sensor module can track GPS signals beyond -158 dBm. For more details see the Atmel press release or the U-Bloc press release. No pricing was announced for the ANTARIS/SuperSense chipsets but a full evaluation kit with enclosure, power supply, antenna, and serial interface is priced at $549. U-Bloc has also posted field test documentation (PDF format) of the module in a variety of indoor and automotive applications.