ashtech ZY-12 Information Supplement page 66

When the MANUAL option is selected, whenever the WAYPT.SWITCH function is
activated (highlight WAYPT. SWITCH and press the [e] key), the receiver
advances to the next leg of the route (Figure 3.36).
7: Range Bearing
This function calculates the range and bearing between any two consecutive
waypoints in the route.
60
Figure 3.36. Next Leg
ZY-12 GPS Receiver