EQUIPMENT KNOWLEDGE/OPERATIONAL REQUIREMENTS QMC(SW) Collins NAV/SR QM-VMS Operator Instructor ETC(SW) Gibbs NAV SAGT Lead Instructor ETC(SW) ClodfelterNAV SAGT Coordinator CDR Chris Atkinson Officer In Charge CSCS Detachment East (757) 445-1671 firstname.lastname@example.org
Q: What is safe navigation?A: Getting somewhere in 1 piece CONSISTS OF => Planning a voyage Dock to dock without incident Track-keeping to the next waypoint Adaptation to changing conditions Ongoing validation of sensors Applying all aids effectively Keen visual lookout all around Backups at the ready NAVIGATION IS A CORE CAPABILITY OF SURFACE WARFARE NAVIGATION AND ALL ITS DATA (LATITUDE, LONGITUDE, HEIGHT, TIME) IS CRITICAL FOR ALL OTHER WARFARE AREAS!
Navigation Status • What do I look for to know if something is wrong? • Standard navigation sensors • Navigation logs and records • Paper charts • VMS
Everything Is Going Well Upon entering the bridge no one “jumps” or gives any response to indicate something is wrong. Nothing looks out of place Everyone is doing their assigned task OOD/JOOD knows exactly what the “big picture” is. There is no noticeable indication of tension. Key Indicators: All logs and records are well kept The navigation table is neat and orderly Watchstanders are not joking around with each other or involved in tasks that will prevent them performing their assigned duties. All watchstanders are on station (QMOW is not in the chart house working on charts, for example).
Not Right or Out of Place Upon entering the bridge you notice signs of tension or jumpiness. OOD/JOOD do not know exactly what the “big picture” is. Not sure of which contact is which or what a contact’s COG, SOG or CPA is. Give data that is not accurate (opposite bearing drift, for example) The bridge is disorderly Food at the SCC Navigation table covered with papers or debris Watchstanders lethargic in their duties • Though none of the previously mentioned conditions are an immediate indication that your ship is in imminent danger, they do indicate a climate of complacency. If left unchecked, something is bound to go wrong in the future.
Pilothouse Advice Looks good right? Here are recommended areas to check: • Is there a DR track on the chart? • Is the DR the correct course and speed? • Is the Deck Log thorough and neat? • Does the Deck Log reflect the correct course and speed? • Does the Position Log reflect a comparison of all posit sources, not just one? • Have the gyroscope repeaters been properly marked with the repeater error and gyro error? • Many Sailors just mark the repeaters with the daily gyro error and forget to check the heading error versus the main gyro. It is a required step, you need to have gyro repeaters which are as close as possible to actual heading.
What Should VMS Look Like? • You should see a chart • All primary sensors are green • Your ship is visible on the screen • Vector arrows should be pointed in a safe direction • None of the vector line should be red (this indicates a sensor is bad) • There should not be a series of “U”s across the screen (this indicates your chart is not corrected)
Proper Position Sensor Selection • In open ocean or coastal navigation • 1st GPS • 2nd WSN-7 • 3rd Visual/RADAR/Composite (if available) • In restricted waters • 1st GPS • 2nd Visual/RADAR/Composite • 3rd WSN-7
Proper Primary Sensor Selection • Heading • 1st WSN-7 • 2nd NAVSSI (RTS) • 3rd DFGMC • Course Over Ground • 1st GPS • 2nd WSN-7 • 3rd NAVSSI (RTS)
Proper Primary Sensor Selection • Speed Over Ground • Same sensor as COG, but opposite sensor • If you have FWD GPS for COG then AFT GPS should be used for SOG • Speed Through the Water • 1st WSN-7 • 2nd Manual (at VMS node) (Whatever source WSN-7 is set up to use is the source VMS will use when WSN-7 is selected)
VMS ALARMS • There are two types of alarms in VMS that require immediate action. • Red alarms are CRITICAL (Primary Sensor) • Yellow alarms are precautionary (secondary Sensors) • White alarms are administrative
Common Critical Alarms • “Invalid Sensor Source” • Occurs when the primary sensor looses input • There is no delay in the alarm. It occurs immediately. • “Position Discrepancy” • All secondary positions are compared at all times. • When any secondary position sensor deviates more than 214 meters from the primary position source, this alarm will activate.
Common Critical Alarms • “Sounding Comparison Can Not Be Made” • Occurs when no depth input is available to VMS • “Safety Contour Violation ” • Occurs when no depth input is available to VMS (always received when previous alarm is activated) • When within a safety contour designated in the ship's safety configuration set up by the VMS operator. • Compares Harbor, approach, coastal and general charts
Common Critical Alarms • “Cross Track Error” • Activated when cross track error is greater than the designated amount set in the nav plan.
Common Precautionary Alarms • “Position time out ” • Occurs when a secondary position sensor looses input • There is a delay of 15 seconds before this alarm occurs. • “Chart warning ” • Occurs when a chart is missing from an active portfolio on any node.
Information About Alarms • Because of the vast number of alarms within the VMS software it is not possible to cover them all here. Those mentioned are the ones you can expect to see relatively often. • For a complete list, See appendix B of the VMS operator’s manual
Purpose of the Gyrocompass Provide to other Ship’s systems: Attitude Rates Pitch Ship’s heading Roll Position and Time Velocities
Inertial Navigation Basics • If we can measure the acceleration of a ship we can: • Integrate the acceleration to get velocity; and • Integrate the velocity to get position. • Kalman Filter: A statistical method for estimating the parameters of a dynamic system, using recursive techniques of estimation, measurement, weighting, and correction. • The filter acts to reduce the variance of the estimate with each measurement cycle. In navigation, the technique is used to refine the positions given by one or more electronic systems. • Basically, the Kalman Filter compares the INS position to the GPS position every 66 seconds. If the two positions compare within specifications, the INS is reset to the GPS position.
Inertial Navigation Basics • An INS measures all motion, including the rotation of the Earth at that latitude, known as ‘Earth-rate’. • In order to determine the proper Earth-rate, the system needs a good velocity input, selected by the technicians from the options at the Control-Data Unit: GPS, then Pitsword, then a synthetic input (I.e. dummy log/shaft RPM) and lastly, Manual. • If the WSN-7 loses it’s velocity input, it becomes UNDAMPED, meaning that it is subject to drifting. This positional drift will increase with time. • An INS is just like a pendulum with an arm equal to the radius of the Earth. Just as the Earth wobbles on it’s axis, an UNDAMPED INS will wobble in an 84 minute period. This is known as a ‘Schuler Oscillation’.
Error Sources for INS • Earth Ellipticity • Earth Rate • Coriolis Acceleration • Longitudinal Convergence • Transverse Coordinates • Instrumentation Errors/Misalignments • Indexing • Computational Errors • Fixes and Resets
How a degraded WSN-7 position can lead to a grounding. ERROR ERROR ERROR Perceived pressure to arrive on time ERROR Lack of Situational Awareness ERROR Failure to use proper Navigation procedures ERROR Failure to adhere to WSN-7 CSOSS procedures Lack of NAVSSI/ COMDAC knowledge WSN-7 was in a Schuler Oscillation that created a 4300yd position error.
OVERVIEW Actual Position Plotted Position
WSN-7 Operating Modes Standby First mode entered upon power up If no action is taken, the system will remain in the inactive state. Align Align Course Align currently being performed Align-C Course alignment complete Fine align currently being performed Align-F Fine Alignment is complete Ready to enter Navigate Nav-C At-Sea Alignment Navigate Must be manually entered if utilizing Dockside or Slave alignment method Entered automatically if utilizing At-sea alignment method Dockside Alignment Preferred Alignment Method AN/WSN-7 settles while ship remains stationary Slave Alignment Transfer data from the other WSN-7 The source AN/WSN-7 must be settled in the Navigate Mode and is available to provide velocity and position reference source At-Sea Alignment Time constraints are involved Should only use if ship is getting underway in less than 4 hours. Align-F Align-C Accuracy increases Align
Operating Modes Mode is displayed in the upper left-hand corner • Standby: • First mode entered upon power up • If no action is taken, the system will remain in the inactive state.
FAULT CLASSIFICATIONS • Operator Advisory • Record and acknowledge fault • Perform required operator action • Non-Critical • Record and acknowledge fault • Determine operating status or alternate mode for continued operation • Critical • Associated with the IMU!!! • FURTHER OPERATION OF THE SYSTEM IS NOT ADVISED! • If displayed on screen, the system will start operating in Dead Reckoning Mode • The system should be tagged out of service • Casualty • Faults associated with IMU functions • The system will continue to run using dead reckoning with degraded accuracy and functionality • RLGN Shutdown • System power automatically turns off! • When able to troubleshoot, fault codes can be viewed in offline test mode
Suggested Additions to Standing Orders • Use the two man rule and use CSOSS to initialize: • WSN-7 • NAVSSI • VMS • Have the QMOW report to the OOD: • Laitude/Longitude and time comparisons on a fix by fix basis. • Itemize a list of error codes for VMS, NAVSSI and WSN-7 • Ensure watchstanders do not silence any alarms without informing the OOD.
Suggested Additions to Standing Orders • Ensure the internet access is available to Navigation Department for: • SIPR: NGA charts and publications, Navy Lessons Learned, Classified Notice to Mariners, Navy Lessons Learned Port Reports, meteorological information and other classified lessons learned sites. • NIPR: Notice to Mariners, NGA Publications, Local Notice to Mariners, Hydolants, Hydropacs and NAVAREAS.
Suggested Additions to Standing Orders • Insert periodic checks on the WSN-7 to ensure that NAVSSI/GVRC is the selected Navigation Data source. • Insert a rule that Combat Systems, Navigation, GCCS, AIS and any other GPS position and time source equipment have periodic comparison for accurate time in GMT and Latitude/Longitude.
Suggested Additions to Standing Orders • Ensure all Navigation Position Logs reflect all GPS sources and other position sources for every fix. When at Navigation Detail, ensure the Navigation Evaluator has assigned a person to periodically check GPS position accuracy against other GPS sources. Report comparisons against the visual or RADAR plot and against other GPS sources.
Suggested Additions to Standing Orders • Institute the “NO FIX” stop the ship rule for piloting waters or at Navigation Detail. Be absolutely sure of position. • Station the Navigation Detail at RADAR landfall or nearly at RADAR landfall, the best comparison is GPS, RADAR, Commercial GPS(COTS)
Suggested Additions to Standing Orders • Conduct Navigation Suite awareness training to address knowledge gaps of Nav Data sources and configuration in junior Officers, FCs, QMs, OSs, ETs and ICs. • Run all the pieces of the Navigation suite in GMT, stay away from local time, if you need local time, use a clock! • Utilize the VMS interactive courseware provided during install to train other watchstanders (Conn, OS, CICWOs)
Suggested Additions to Standing Orders • When conducting steering checks ensure all steering systems are checked, both in manual and auto-steering modes. • If you have discontinued using the Magnetic Compass Record Book, then consider re-establishment, if you have not discontinued, then don’t disestablish.
ResourcesCSCS Communities of Practice • All CSCS courses are affiliated with a Community of Practice and tied into the formal classroom training with instructor accessibility through: • Message boards • Feedback forums • Access to curriculum for refresh and advanced learning • Pre-Requisites • Access to Study Material Resources CoP • Sample pre-tests and post-tests • Access to subject matter experts • Sailors have 24-7 access to classroom information, instructors, and classmates All Ratings have CoPs. https://wwwa.nko.navy.mil/portal/surfacecombatsys/etcop/home/anwsn-7cop