1 Autosub Mission Planning and Operations Dr. Miles Pebody Ocean Engineering Division Southampton Oceanography Centre

2 Overview l Equipment l Pre-Mission Planning l Mission Preparation and Initiation l Mission End and Post Mission

3 Equipment

4 Equipment: Computing Resources l Three Networked PCs Mission programming, mission management and vehicle telemetry.Mission programming, mission management and vehicle telemetry. Acoustic TrackingAcoustic Tracking Data ProcessingData Processing Tershelling April 2000

5 Equipment: On Surface Communications l Lonworks VHF Radio Modem (range 0.5Km) l Ethernet VHF Radio Modem (range 0.5Km) l Orbcomm Satellite Communications l Argos Satellite Tracking

6 Equipment: Subsurface Communications l 23-33KHz Acoustic Tracking, Telemetry and Commands l 10-14KKz Tracking (telemetry in development)

7 Pre-Mission Planning

8 l Mission Requirements l Mission Navigation l Control Modes l Autosub Safety Issues l The Mission End - Recovery

9 Mission Requirements l Instruments/sensors l Data sampling l Area of operation l Vehicle critical factors Power availabilityPower availability Depth ratingsDepth ratings

10 Mission Navigation Example: track of 110 km mission off Fort Lauderdale. Coast, Florida. l Waypoint selection l Co-ordinate System Cartesian (X/Y metre offset)Cartesian (X/Y metre offset) Polar (latitude/longitude)Polar (latitude/longitude) l Navigation Mode Selection Heading onlyHeading only Heading to positionHeading to position Follow track between two positionsFollow track between two positions

11 Control Modes: Depth/Altitude Control Depth control Altitude control - terrain following l Autosub can also be programmed to profile Up/Down at constant pitch angles

12 Mission Safety Issues In water obstaclesIn water obstacles Terrain - vehicle pitch controlTerrain - vehicle pitch control Surfacing zonesSurfacing zones Mission depth and altitude limitsMission depth and altitude limits Emergency abort timeoutsEmergency abort timeouts

13 Mission Preparation and Initiation

14 Mission Preparation and Initiation l Mission Script l Configuration Script l Mission Script Checking l Pre-Launch Tasks l Post-Launch / Pre-Start Tasks

15 Operations: Mission Preparation Mission Script Editor ConfigurationEditor Control parameters Sensor parameters Safety limits EAS timers + limits MissionCompilerWarnings Go!Stop MissionCommander + Monitor History File RadioModem Down-loader Mission Simulation

16 Operations: The Mission Script // When satisfactory GPS fix has been acquired dive and track follow: // Set timeout to 500 seconds. WHEN( GotGPSfix)// When GPS fix acquired ……… Timer( 500),// Set timeout of 500 seconds. Depth( 10),// Set depth mode to 10 metres. MotorPower( 400), // Set motor mode to Power 400 Watts. PositionP( N:56:27.5, W:5:29.4); // Set position mode and demand // Next line, when reached end of the track …… WHEN( GotPosition)// When Got there (OR timeout) ……… ………

17 Operations: The Launch Early launches through ship’s ‘A’ Frame.Early launches through ship’s ‘A’ Frame. Now we use a gantry system.Now we use a gantry system.

18 Operations: Monitoring unattended missions GPS position Orbcomm data link Terschelling Autosub campaign March 00 Text message on cell phone GPS Orbcomm Status message

19 Mission End and Post Mission

20 Mission End: Autosub Relocation. l Local ARGOS tracking to horizon l Surface radio telemetry within 0.5 Km l Acoustic Telemetry within 1 Km (soon 6Km) l Acoustic tracking within 8 Km

21 Mission End and Post Mission l Logger Data Recovery l Autosub Recovery l Navigation Postprocessing and Engineering data examination

22 The End Dr. Miles Pebody Ocean Engineering Division Southampton Oceanography Centre

23 Autosub Systems: Navigation l GPS or DGPS fixes on the surface update the position estimate. lSpecial Navstar GPS antenna overcomes problems of washover on tail mounted antenna. lBroadcast (300 kHz) DGPS corrections used. l Uses RDI 300kHz Doppler sonar (250 m range) for velocity.& Seatex MRU6 compass for rotation into earth co-ordinates. l Biggest problem is heading dependent compass errors. l Errors can be substantially reduced to about 0.5-1% of distance travelled with calibration. l Calibration involves a short box mission.

24 Autosub Systems: Heading Control HeadingHeading Line Of SightLine Of Sight - ( Head towards demanded Waypoint). Track FollowTrack Follow - ( Follow Straight Line Track Between Two Waypoints). Modes of Operation.

25 Future Developments l Integrated mission planning tools including mission simulation and replay. l Modify Mission Control and Emergency Abort for the more complex environment of under-ice missions. l Power source - fuel cells, semi-fuel cells. l Improved Collision Avoidance in the horizontal plane. l Improved Navigation. Use Ring Laser Gyro based INS. From 1% to 0.1% of distance traveled. l Improved Acoustic Communications and Location.