missing position statements

i’m using the magellan/thales AC12 gps unit, and trying to figure out why it sometimes fails to spit out position statements. it should be giving one position statement a second but sometimes drops out for several seconds at a time.

here is an example:

POS: 230007.00,+3752.46749,-12215.51734,56520223,419214501,10,14.80,0.00,-0.00,3.30,1.70,2.80,1.00,0,6,0,140

RAW: 1218841209 PASHR,POS,0,06,230007.00,3752.46749,N,12215.51734,W,098.98,014.8,000.0,-000.0,3.3,1.7,2.8,1.0,BQ002<87>!!!

MCA: 1,17,64,94,2,2,24,5,38,0,193,2C0872424E75473F,B1B7F834855B59FF,00C49B64,8001FFF4,10,4

MCA: 1,0,11,24,35,12,2,24,5,40,0,C131C6E9FD32AE91,3FB3B61F9CEEFAD9,004C6CC3,64000064,10,22

MCA: 1,144,31,67,7,65,63,177,183,230,151,AE9BBDFF00F4E064,8000220D0A420902,18052A00,6CA2D3CB,183,113

MCA: 1,2,8,48,56,6,2,24,5,45,0,070125FCFF9E3FB2,289F45D46C310133,19E46400,00F04A0A,10,220

MCA: 1,1,15,38,145,7,2,24,5,44,0,C14611CC0C97B735,3FB2F5F308B28D54,FF9DA090,64800113,59,59

MCA: 1,0,11,24,35,12,2,24,5,41,0,C131C4FB5D927036,3FB3B624E1EC59BC,004C9E8D,64000019,33,33

POS: 230009.00,+3752.46753,-12215.51735,56520222,419214509,10,14.80,0.00,-0.00,3.30,1.70,2.80,1.00,0,6,0,137

RAW: 1218841211 PASHR,POS,0,06,230009.00,3752.46753,N,12215.51735,W,098.99,014.8,000.0,-000.0,3.3,1.7,2.8,1.0,BQ002<87>!!!

the RAW statement is the actual statement received by the gps unit, the POS statement is just a parsed version. so there was a POS for unix time 1218841209 and 1218841211 but not 1218841210. can the MCA statements give me any clues as to the reason for the missing POS? anyother troubleshooting steps i can take?