1. GISMO Navigation John Sonntag EG&G Technical Services, Inc. 31 January 2007

2. Navigation Techniques Two navigation tools available Soxmap  Used for May 2006 GISMO  Standard Twin Otter tool  Visual aid for flight crew  Best for following curved path Course Deviation Indicator (CDI)  Will be used for 2007 GISMO  Can couple to aircraft steering  Good repeatability for long straight lines

3. 23 May 2006 Mission Plan Flight plan was out-and-back Thule to Camp Century, then southeast along 18 May 1999 ATM/KU flight track Inbound leg offset 25 m to south of outbound Constant 10,000' pressure altitude

4. 060523 Steering Performance (1) Red dots: outbound leg Blue dots: inbound leg Black lines are the target lines Target lines are separated by 25 m Top panel is at 300 km along-track from Thule, bottom at 400 km Inbound/outbound separation in top panel is ~35 m Inbound/outbound separation in bottom panel is <=175 m

5. 060523 Steering Performance (2)

6. 060523 Steering Performance (3)

8. 24 March 2006 P-3 Steering Error with CDI

9. Lessons Learned from May 2006 2006 GISMO flight used Soxmap / Twin Otter combination  Configuration more suitable for outlet glacier work  Steering within +/-50m, could be better 2007 GISMO flights will use CDI with P-3  Better repeatability for straight flight lines  Consistent 25-m separation still difficult to maintain More info: atm.wff.nasa.gov; click “Aircraft Navigation”