Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
37 Cards in this Set
- Front
- Back
|
State the considerations for transport of LPG Cylinders |
Carefully handled and not to fall on each other Secured to prevent movement or physical damage 25L stored in open environment |
|
|
Checking of Hydro Stores |
Check equipment and ensure everything is accounted for Sign documents Ensure items are in working order |
|
|
Procedure for packaging and dispatch of ROS |
Dispatched by courier or airfreight Data rendered for AH521 and Hydrographic Document & Issue Voucher AH520 |
|
|
Define a Hydrographic Survey |
Charting of an area that provides basic data for the compilation of nautical charts that focus on features for safe navigation |
|
|
5 fundamental parts of Hydrographic Survey |
Position Orientation Scale Shape Detail |
|
|
5 steps involved in sequence of Hydrographic Survey |
Hydroscheme Geospatial/survey instruction Data collection Report of survey Survey appraisal/validation |
|
|
5 areas of information that are produced in Hydrographic Survey |
Coastline Depths Oceanographic data Tides and Currents Physical properties of the water column |
|
|
Structure of the ROS |
Submission of data: problems encountered, amount completed and thoroughness of the Survey Part 1: describe the conduct of survey under mandatory headings Technical Pages: technical worksheet (NavVal, personnel sheet) |
|
|
What is QMS |
A computer application on the AHO intranet and DEFWEB that employs a database and search engine to deliver Survey documentation in a controlled environment |
|
|
Purpose of Survey planning |
Development of an idea for a survey to the planning conducted by the Ship to fulfil the task |
|
|
Reconnaissance of a Survey |
Acquire necessary data to permit the best and economical survey to be carried out. |
|
|
Steps involved in planning a Survey |
General Survey Plan: training, software, equipment maintenance, logistics, data requirements Site Specific Plan: survey lines, datum, data density, personnel |
|
|
3 phases of Survey |
Office: timings of reconnaissance and actual survey, personnel involved, equipment required, documentation Field: establish local contacts, network design, permanent marks, prove plan Report: the final plan, equipment & manpower, description of the network and realistic estimation of time required |
|
|
Relationship between Geoid and Ellipsoid |
Geoid is an equipotential surface of the earths gravity field, closely approximates Mean Sea Level. Ellipsoid is an arbitrary mathematically defined geometrical construct that closely approximates the earths surface |
|
|
How is Ellipsoid defined |
It is defined by the semi-major axes, semi-minor axes and flattening |
|
|
List 4 reference Ellipsoid |
WGS84 GDA 2020 & 94 ANS ADG66 |
|
|
Latitude |
Circles running around the globe parallel to the equator measured from the equator. Lines run parallel north-south |
|
|
Longitude |
Semi-circles running from the North Pole to the South Pole (East-West). Reference line the Greenwich meridian. Longitude cannot exceed 180 |
|
|
Great circle |
A circle that will cut the sphere into two equal halves |
|
|
Relationship between geodesy projections and grid |
Geodesy lat and long projected on a transverse Mercator projection are distorted and don’t always appear as straight lines which make plotting and calculations difficult. A grid is a sequence of squares superimposed on a projection so that plotting and calculations can be done with simple trig |
|
|
Theory of GNSS |
GNSS provides a position that is determined by means of receipt of radio signal from a satellite constellation in orbit around the Earth. It’s a real-time, all weather, 24 hour worldwide and 3 dimensional positioning system |
|
|
Explain GNSS Signals |
Transmits data by microwave signals that are sent in 3 parts Navigational Message: time, SV Health Ephemeris Data: SV precise orbit info Almanac: SV course orbit time, Ionosphere model |
|
|
3 main categories of GNSS errors |
Satellite Error: clock errors, orbit errors Atmospheric Errors: ionosphere errors, tropospheric errors Receiver Errors: clock error, station co-ordinate |
|
|
dGPS & WAdGPS |
dGPS is a ground based augmentation system for GPS that can improve accuracy to +- 5 metres. It uses a system of ground based base stations whose position is accurately known. WAdGPS is a form of dGPS where corrections are received from a network of reference stations established over a wide area. |
|
|
How GNSS Receiver works |
Determine a highly accurate position on the earths surface by means of a process called carrier wave phase measurement |
|
|
3 methods of GNSS (PPK) |
Absolute: positions determined from observations recorded by a single geodetic receiver Classic static baseline: two receivers, both stationary, one on a known mark one on a unknown mark simultaneously recording. On the fly: two receivers, one stationary on a known mark the other mobile simultaneously recording |
|
|
PPK Concept |
1. Base and rover record positions simultaneously 2. One or more rovers in motion to observe baseline to static base station 3. Continuous satellite lock during observation 4. Post processing to apply correction |
|
|
Field Adjustments |
Before first use Long periods of storage Large temperature differences Long/rough transportation |
|
|
Met observations |
Temperature read to 1 degree Barometric pressure: pressure read to mb/hPa Humidity: 2% |
|
|
Field Adjustments |
Before first use Long periods of storage Large temperature differences Long/rough transportation |
|
|
Met observations |
Temperature read to 1 degree Barometric pressure: pressure read to mb/hPa Humidity: 2% |
|
|
How to minimise total station errors |
Good atmospheric conditions Secure & firm Not exposed to direct sunlight Legs and unit target are level Adapt to temperature, 2 minutes per 1 degree difference in temperature. |
|
|
Field adjustment should be conducted? |
Before first use Long periods of storage Large temperature differences Long/rough transportation Special order work |
|
|
Met observations |
Temperature read to 1 degree Barometric pressure: pressure read to mb/hPa Humidity: 2% |
|
|
How to minimise total station errors |
Good atmospheric conditions Secure & firm Not exposed to direct sunlight Legs and unit target are level Adapt to temperature, 2 minutes per 1 degree difference in temperature. |
|
|
Infra red measurement |
1-600m |
|
|
4 satellites used and why? |
X- latitude Y- longitude Z- height T- time X,y,z determines the position, t is to adjust for the error in the receiver clock |
