ashtech ZY-12 Information Supplement page 106

Note: It may take 10-20 minutes for the receiver to enter Y-mode the
first time.
The receiver is not in Y-mode if the response is "$PASHR,KEY,N". If the
receiver is not in Y-mode, continue to monitor the receiver for an addi-
tional 10-20 minutes using the KEY query until you receive the
"$PASHR,KEY,Y" response, or by observing the "LY" indications on
screen 0.
Verify that each satellite has entered Y-mode by typing "PASHQ,MBN"
<Enter> and observing the MBN message flag. The data field in position
18 of the $PASHR,MBN message indicates "25" when the receiver is in
Z-mode for L1, and "24" to indicate the receiver is in Y-mode. Similar val-
ues in data field position 28 are for L2.
Type "$PASHQ,MBN" <Enter> and check the field for the 24 indicating Y-
mode for each satellite and for both L1 and L2 frequency. Note if there are
6 satellites locked in Y-mode, then there should be 12 indications of the
"24" response.
11. LOCK ALL CHANNELS TO ONE SATELLITE IN "Y-MODE"
1. Verify that the receiver has locked onto at least 4 satellites by observing
screen 0.
Verify that at least one satellite has a S/N value > 50. Note the satellite
with the highest S/N.
Observe screen 2 and verify that the receiver has produced a position.
2. Go to screen 7. Press <e>. Set AUTO SELECTION to "N". Set "N" for
each satellite starting at "1" up to the satellite noted in Step 11.1. Leave
that satellite set to "Y". Press <e>. Now go to screen 8. Press <e>. The 3-
digit field at the bottom of the screen should be highlighted. Enter in "987"
in that field and press <e>.
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ZY-12 GPS Receiver