sail-world.com
 
 
News Home Cruising Photo Gallery Video Gallery
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 ...






News - USA and the World

Volvo Ocean Race 2014-15 CEO Knut Frostad talks (Part I) *Feature by Rob Kothe and the Sail-World team,










Maxi yacht rendezvous this September in Sardinia by International Maxi Association,


















America's Cup: Team NZ wish Davis well with new team by Richard Gladwell, Sail-world.com/nz,


Fisher's View: Sailing perfection at Hamilton Island- Day 3 by Bob Fisher, Hamilton Island, Queensland




2014 Formula Kite World Championship Day 1 by Markus Schwendtner, Istanbul
























Opera House Cup - Images by Ingrid Abery by Ingrid Abery/Sail-World.com,


Teams descend upon Cowes for inaugural J/111 World Championships by Stuart Johnstone, Cowes, Isle of Wight, England






Sopot Match Race - Poland's Tour debut deemed a triumph
Vineyard Race celebrates 80th running of the East Coast classic
Nanjing Youth Olympic Games: Young sailors begin racing on Lake Jinniu
AWT Quatro Desert Showdown - Victory for Morgan Noireaux
Sevenstar Round Britain and Ireland Race - Day 8: Test of endurance
Bart's Bash: Over 2300 entered from 588 yacht clubs - Join here
Halifax ready to welcome the world at 2014 IFDS World Championships
RC44 World Championship title to Bronenosec + Video
Audi Hamilton Island Race Week: Day 2 Images by Crosbie Lorimer
IFDS Worlds - Gary Jobson to attend opening ceremonies
Melges 32 U.S. National Championship - Dalton DeVos crowned champion
2014 Nanjing Youth Olympic Games trailer
2014 Chicago Grand Slam - Canfield wins
Round Britain and Ireland Race - Varuna takes overall lead
Audi Hamilton Island Race Week; Crosbie Lorimer Day 1 Images
Fisher's View: Hamilton Island Race Week - Day 1 - Stayin' Alive
CORK Olympic Classes Regatta 2014 - Day one
Youth Olympics: practice over, athletes welcomed, time for YOG sailing
Round Britain and Ireland Race - Record for Artemis-Team Endeavour
2014 Melges 32 U.S. National Championship - Day 2
Sevenstar Round Britain and Ireland: Artemis sets fourth course record   
2014 Chicago Grand Slam - Top seeds survive as semi-finalists   
420 and 470 Junior Europeans - Breezy day 4 in Gdynia   
RC44 World Championship - Dramatic improvement for Artemis Racing   
18' Skiff International Regatta - Action begins August 25th   
Round Britain and Ireland Race - Challenging conditions arise   
Round Britain and Ireland Race - Record-breaking monohull victory   
Round Britain and Ireland Race - Dongfeng Race Team finishes third   
RC44 Marstrand World Championship - Bronenosec the star performer   
Bahamian Olympic Sailor to carry flag in honour of Sir Durward Knowles   
Sevenstar Round Britain and Ireland Race: Records continue to tumble   
Sevenstar Round Britain and Ireland Race: Course Record for Team SCA   
Round Britain and Ireland Race - Team Alvimedica completes the race   
2014 Melges 32 U.S. National Championship - Day 1   
420 and 470 Junior European Championships - A crazy race day 3   
2014 Sevenstar Round Britain and Ireland Race: Monohull record smashed   
2014 Chicago Grand Slam - Top seeds take the early lead   
Frostad proud to have seven Volvo Ocean Race boats with seven sponsors *Feature   
RC44 World Championship - Bronenosec Sailing Team on form   
Round Britain and Ireland Race - Dongfeng defends third position   


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  


















Switch Default Region to:

Social Media

Asia

Australia

Canada

Europe

New Zealand

United Kingdom


http://www.sail-world.com/event_images/image/Twitter_logo_small.png http://www.sail-world.com/event_images/image/FaceBook-icon.png  http://www.sail-world.com/event_images/image/RSS-Icon.png

United States

Cruising Northern

Cruising Southern

MarineBusiness World

PowerBoat World

FishingBoating World

 

Contact

Commercial

News

Search

Contact Us

Advertisers Information

Submit news/events

Search Stories/Text

Feedback

Advertisers Directory

Newsletter Archive

Photo Gallery

 

Banner Advertising Details

Newsletter Subscribe

Video Gallery

Policies

 

 

 

Privacy Policy

 

 


Cookie Policy

 

 



This site and its contents are © Copyright TetraMedia and/or the original author, photographer etc. All Rights Reserved.  Photographs are copyright by law.  If you wish to use or buy a photograph contact the photographer directly.
XLXL NEW US
LocalAds   DE  ES  FR  IT