sail-world.com
 
 
News Home Photo Gallery Boats for Sale Sail-World Racing Cruising Int MarineBusiness-World FishingBoating Magnetic Is RW
Sail-World.com : Something to ponder - Is your GPS system 100% safe?
Something to ponder - Is your GPS system 100% safe?


'eLoran - A possible solution to nervousness about lost or jammed GPS signal.'    .

How safe is your GPS system? Even if you have multiple redundancies on board your sailing boat, what happens if the signal actually fails? How could that happen and what about the alternatives to GPS now being rolled out? Would they be a solution? - or if not, now that fewer and fewer sailors are carrying complete paper charts, what IS the solution?

Recently, the RYA's Simon Jinks wrote about just this issue:


Within a decade, our skies could be full of new GNSS (Global Navigation Satellite Systems), such as Europe‘s Galileo, Russia’s Glosnass, China’s Compass and India’s GINS. They will all be vying for space above our heads feeding the world’s addiction for a PNT(position, navigation and timing) fix.

Each new GNSS requires approximately 20-30 satellites in order to operate, so there may be well over 140 in orbit.
If one satellite or an entire system goes down, there will be plenty of others to take its place.

The current thought is to make the systems interoperable so a chipset within the on-board GNSS receiver will compute all the accessible data from the different systems and use the best one for your fix.

Spurious signals:
However, there may be a problem. The signals used by GNSS systems are very weak and are vulnerable to interference. The frequency range of the new GNSS systems are all similar and with more satellites operating, comes the possibility of more interference or noise leading to a loss of signal tracking with the resulting inability to compute a reliable fix.

GNSS is also susceptible to satellite failure, antennae failure, and natural solar events and to the illegal use of jamming equipment or accidental jamming from TV antenna amplifiers or stray emissions.

An internet search for ‘GPS jammers’ produces a vast amount of GNSS jamming equipment commonly used by vehicle thieves and disgruntled employees unwilling to have their works van tracked by their boss. These are becoming more of a concern to the maritime world.

Two separate trials were carried out Flamborough Head and Newcastle-Upon-Tyne , on the NE coast by the GLAs (General Lighthouse Authorities) to establish the effect of GPS jamming on maritime operations. Trial vessels were monitored as they transited the affected area and the results showed that positions were out by up to 22km and speed over ground rose to over 100 knots in cases.

Even more worrying was the fact that under very low signal strength jamming, the positions computed by the on-board GPS would show a slight error to the vessels position which may go unnoticed but could be significant to the safety of the vessel.

A possible solution:
The vulnerability of GNSS systems has led Britain's General Lighthouse Authorities (GLA) to get involved in the development and testing of a stand-alone navigational system that could provide a back-up if GNSS fails. This back-up is eLoran (enhanced Loran), a low frequency, and terrestrial system, based on a much modernised and updated Loran technology.

LORAN C (Long Range Navigation) has been around for years and was the one of the primary navigational systems accompanying Decca before GPS. It uses low frequency radio waves from land based radio transmitters and depending on the system used, gives positional accuracy to about 100 – 400m.

eLoran offers positional accuracy of 10m (95%) and work is being performed on the development of a Loran chipset to allow a receiver to compute a position based on eLoran or GNSS.

The high power, low frequency signal of eLoran is harder to jam and thus could compliment GNSS; this is why the GLAs are championing eLoran to provide a cost effective back-up to GNSS.

Accuracy:
The main difference between Loran C and eLoran is the inclusion of a Loran Data Channel on the signal that allows timing and corrective information to be sent to the receiver, increasing accuracy. The system has been shown to work providing accurate timing and positioning information to coastal and medium distance offshore applications.

Recent testing has produced very positive results for eLoran. The successful implementation is dependent on governments agreeing to upgrade their Loran C infrastructure to eLoran and commit to long term funding.

The way ahead for marine navigation and safety is electronic and GNSS offers a global solution, but there needs to be an effective back-up system to catch GNSS when it falls.

This offers a very good reason for the prudent sailor to continue to carry paper charts against the unthinkable occurrence of an inaccurate, jammed or completely disappeared PNT system on your sailing boat.


by Simon Jinks, RYA/Sail-World Cruising

  

Click on the FB Like link to post this story to your FB wall

http://www.sail-world.com/index.cfm?nid=108170

1:41 AM Sun 16 Jun 2013GMT


Click here for printer friendly version
Click here to send us feedback or comments about this story.

Click for further information on
Practical

Related News Stories:

02 Jun 2013  Pocket Mariner launches nautical charts and navigation App
22 May 2013  Inverter Installation: Troublshooting 101
21 May 2013  Yacht Track Library - an ingenious new tool for cruising sailors
18 May 2013  Digital Media Locker plus Blue Tooth connection for a dry iPhone
15 May 2013  Ten quick tips to make boat cleaning less of a chore.
11 May 2013  Fuel filters recalled by Osculati
07 May 2013  Choosing a chartplotter program for ActiveCaptain users
28 Apr 2013  Words of wisdom from a Cruising Guru
16 Apr 2013  Love your sailing boat's belts and they will love you in return
05 Apr 2013  World's tiniest PLB now certified for use
MORE STORIES ...






Sail-World Cruising News - local and the World



'Sailing Adventures in Paradise' by Vincent Bossley by Noonsite Reviewer/Sail-World,
















Pam, 90-year-old pearling lugger, to sail again by Sail-World Cruising round-up,












How sailors really do have a voice in the future of our oceans by Sandra Whitehouse, Sailors for the Sea,




Message-in-a-bottle record - 102 years by AFP/Sail-World Cruising,
















Canadian solo sailor rescued north of Auckland by Sail-World Cruising round-up,








Ipad and sailing boats in Australia/NZ - What works and what doesn't *Feature by Andrew Keays, Island Cruising Association,








Dramatic MOB Pacific cold-water rescue - the personal account
Merchant Shipping Chalks Up Another Rescue - Tanker Saves Yacht Crew
Check this sailing gear more often during the season
Multihull Solutions Whitsunday Rendezvous 2014 – Entries sailing
SOLAS fundraiser to take place at Gosford Sailing Club
Laura Dekker presented OCC's Award of Merit Sat 05 April in Whangarei
Free online fuel spill course - how much do you know?
Smaller but plenty of space: The Nautitech Open 40
Product of the Week: Chafe guards save lines from friction
Government sneaks through the 'Affordable Boat Act'
Japan's Antarctic whaling program harpooned
Yacht of the Week: Kokomo III - and she could be yours
To Sea in a Sailing Ship: the glory days - at CYCA TOMORROW!
Life-shattering event sends 'rookie' couple sailing the world
Mysteries of the seas, happening right now - missing, sunk, foul play
Sail Norway and Russia this summer - your own boat, or charter
Sunshine4kids' 'Fleet of Hope' sets off again
3,200-year-old boat found in Croatian waters
Product of the Week: the LineGrabber
So-called 'Med Mooring' - handy in some anchorages, and here's how
Canadian storm bomb threat - sailors advised: get off the water!   
Carbon monoxide poisoning - is it possible on YOUR boat?   
Go crazy about whales in a special family fun day at the museum   
Southport Yacht Club achieves Gold Anchor status   
Sailing family condemmed for taking 3-year-old on circumnavigation   
New contract-free plan for satellite communicator on your smart phone   
Melbourne Boat Show earlier this year - 12 to 16 June   
Southport Yacht Club will host a free 'Discover Sailing Day'   
Farmer sails his super-size pumpkin across lake - a New Zealand first   
Yacht of the Week: The Dashew creation: no sails, but eco-friendly   
No laughing! Sailing mistakes I don't want to make   
Destination: From Moscow Sea to the White Sea   
Land sailors of India on adventure across the Rann   
Future of Auckland's rescue helicopters in doubt   
A Paint App to (almost) replace your marine store assistant   
Amazing Whales – Evolution and survival opens tomorrow   
Maritime Alert - Dangerous conditions forecast for NSW boaters   
Club Marine Pittwater Sail Expo - Sea Guardian on display at RPAYC   
Hilary Lister and Nashwa Al Kindi set a new trans-ocean record   
How to anchor and 'never utter a word'   


For this week's complete news stories select    Last 7 Days
   Search All News
For last month's complete news stories select    Last 30 Days
   Archive News







Sail-World.com  



















 
Our Advertisers are committed to our sport, please support them!
This site and its contents are © Copyright TetraMedia Pty. Ltd and/or the original author, photographer etc. All Rights Reserved.

Photographs are copyright by law. If you wish to use or buy a photograph you must contact the photographer directly (there is a hyperlink in most cases to their website, or do a Google search.) with your request.

Please do not contact Sail-World.com as we cannot give permission for use of other photographer’s images.

Only if the photographer named on the image is Sail-world.com, Powerboat-world.com, Marinebusiness-world.com or NZBoating-World.com.
Contact us .
Ph: +61 2 8006 1873 fax: +61 2 8076 0459 or complete our feedback form    Contact us .
   View our Privacy Policy.    [Go Home]     [  Banner Advertising Specification]    [Bot Archive ]

Customised news feeds -Marine Industry companies, Clubs and Associations have their own customised version of our news feed on their website.
Look_here_to_see_examples

X6XL NEW Cru SH