Due to a recent firmware update from our GPS manufacturer, Crossbow has published a service bulletin for the NAV425EX which contains details about a possible software update that may affect customers that are currently flying the NAV425EX.  The software update provided by the GPS subsystem manufacturer contains improvements that eliminate the possibility of erroneous data during very specific satellite configurations.  In addition, we have made some improvements to the magnetometer performance and BIT (built in test) status inside the NAV425EX.  You can find the full details of this service bulletin, including the units affected using the link below.  

http://www.xbow.com/Support/Support_pdf_files/Service_Letter_NAV425-06-07_A.pdf

Sincerely,
 
Michael Smith
Application Engineer Inertial Systems
Crossbow Technology
Email: msmith@xbow.com