nav

• Propagation does the hyperbola in the LORAN CHART based.

  
  

  ground wave
• Ground waves are corrected in NM using 162,000 nm.
• LORAN-C receiver identifies a station by sending unique details, such as by the pulse it transmits.
• The LOCUS of POINTS having the same TIME DIFFERENCE from a specific master secondary pair form a Line of Position (LOP).
• The frequency of LORAN-C is 100 khz.
• The “NOMINAL GROUND WAVE RANGE” is considered to be 1,200 – 1,500 miles.
• Satellite navigation is a navigation system that fully exploits the doppler effect to accurately determine a position.
• Satellites orbit is geostationary and follows the earth’s curvature.

  
  

  LAW does NOT APPLY to an artificial orbiting satellite.
• GNSS system provides a position fix with accuracy up to within one meter.
• GPS orbits the earth in 12 hours.
• Frequencies transmitted in the navigation satellites are 1227 MHz and 1575 MHz.
• Geodesy is a science concern with the exact positioning of the points on the earth’s surface.
• The distance from the earth to the satellite moves in its orbit is 26,560 km.
• Automatic Identification System (AIS) transmits the vessel’s static data, such as every 6 minutes and on request.
• AIS system is composed of, land & sea based AIS Data Transfer Network Transmitters.
• AIS modes operating modes allows data transfer occurs in response to integration from a ship or competent authority, such as autonomous & continuous.
• Type of vessels does AIS type A is NOT applicable or mandatory to be carried onboard, for vessels engage in domestic trade.
• AIS transponders automatically broadcast information such as their POSITION, SPEED & NAVIGATIONAL STATUS, at regular intervals that built into the transponder. VHF TRANSMITTER
• AIS information is used in collision avoidance for water transport, such as marine radar.
• Electronic Depth finder operates on the principles that sound waves travel at a constant speed through water.
• Frequency measurement is used in a Doppler log.
• Acoustic energy is the energy transmitted perpendicularly from the transducer to the seabed.
• The velocity of the sound waves in seawater is 1,500 m/sec.
• 100 short pulses / minute is the rate of the short pulses of sound vibrations periodically produces by Echo-Sounder.
• Gain should be adjusted in order to record the clearest echo lines on the echo sounder.
• Density due to different temperature layers and air bubbles are two errors that affects the Doppler log.
• Echo Sounder reading is applied to determine the depth of the water, by adding the DRAFT of the Vessel.
• Compass Course is found by applying the compass error, in terms of variation and deviation ].
• NOT continuously transmitted by AIS equipped ships.

  -        COURSE OVERGROUND
• What is GEODESY?

  -        Science concern with the exact positioning of the points on the earth’s surface.
• Combining Variation and Deviation results in Magnetic Compass Error.
• The course in which a ship wants to make good is referred to as True Course.
• Gyrocompass error is expressed in degrees of E or W.
• Navigational equipment that is based on a fast-spinning disc and rotation of the earth is known as Gyrocompass.
• When a ship requires magnetism, it is indicated by the term Induced Magnetism.
• A piece of metal will be magnetized when in regions of concentrated magnetism, this is referred to as a Pole.
• Defined as reflection right or left of the magnetic meridian caused by magnetic properties of the vessel, Deviation is a term in navigation.
• Magnetic Heading is greater than the compass heading, this is referred to as East.
• Not causing variable deviation of electrical if placed too close to the compass, Magnetic Cargo is a term in navigation.
• When the Variation is not constant, it is different with every change in geographical location, this is referred to as Geographical Location.