Argos categorizes locations by accuracy into classes (B,A,0,1,2,3).  The
classes are based on satellite/transmitter geometry during the message
reception and transmission stability: 

Standard locations calculated from at least 4 messaes
received during the satellite pass:

	Class		Estimated accurance in latitude and longitude
	3		< 150 m
	2		150 m < accuracy < 350 m
	1		350 m < accuracy < 1000m
	0*		> 1000 m

*	class 0 is for special cases. On special requests and extra money

.	A		only 3 messages received, no estimate of location 		
			accuracy
.	B		2 messages received, no estimate of location accuracy

. rejected locations

Since I cannot hole letters in the raw files, if any location class came as
an A or B I tunred it into a 0