GPS issue

[Dale Tanski]

Hey, no matter what your political views are this article is a must read if you have a GPS, chartplotter or a navigation system.  This is scary stuff!  One minute your on course for your favorate anchorage and the next you are in the parking lot of a K-Mart. This does not look good. 
I read two other articles over the past few months.  The first one talked about ships loosing their headings along the east coast.  The second talked about airplanes and how Garmin was recalling one of their GPS units thinking they had a design issue.  The 2nd article also began talking about the possibility of terrorists jambing our GPS signals. Now it would appear we know the rest of the story.

http://www.washingtontimes.com/news/2011/feb/7/obama-to-america-get-lost/

Dale

[slokat]

Well my Garmin thinks that even though it's in Morro Bay harbor - that it's actually sitting on a hill above Lopez lake, (inland 20+ miles and about 90 feet above sea level) no matter what downloads & resets I've been through....   I'll retire it for a chart plotter when I work my way around to it, after other more important repairs & upgrades.

[Bev & Billy on Sta-sea-dawn]

This may not be the palce for this question...but I can not locate any subject matter through "search".

Can a laptop, note book or Ipad with an App, be used to navigate

[Jim Cozy]

yes, absolutely, sort of. it is a large and complicated issue with many issues to be decided before plunging in. simply put, a $100 gps plug-in for the computer, electronic charts and a program downloaded, and you are on your way. for a very complete review of the subject, read "Get Onboard with E-charting" by Mark and Diana Doyle. good luck. Jim

[SailingSeaDragon]

Dale,

BoatUS and others have been screaming about this for a year and half. I have written to my senator numerous times with my concerns. For my troubles, I have received several form letters thanking me for my support (he is such a Richard  ).

Garner

[PeteW]

As a former Avionics Engineer for the company that puts the cockpit in nearly every airplane in the sky, the use of GPS for navigation has been and remains ill advised for the simple reason that GPS reception is too easily compromised. The vulnerability of GPS to interferers is not due to activity from terrorist nor is it some nefarious conspiracy by the Obama administration but rather a weakness in the design of the GPS receiver itself. GPS reception most always will be compromised when the GPS receiver is co-located with other transmitters even though these sources of interference can be completely out of band of the GPS receive frequency by hundreds of MHZ. So expecting a GPS receiver to operate on board an aircraft is a tall order. And you can't blame the FCC, they do a good job.

The GPS receiver vulnerability is the result of nearby RF interference exceeding the third order intercept (IP3) of the low noise amplifier (LNA) in the active GPS antenna. Typically interferer of less than 20 dBM (less than legal FCC Part15) can compress the GPS LNA and result in the loss of signal. This interference can come from your co-located Radar, AIS transponder, a hand held VHF or a noisy alternator.

Your Congressman can do nothing about this. Instead you need to write to  Garmin and other manufacturers and ask them to design GPS front ends that have greater linearity (higher IP3) and much better adjacent carrier rejection (SAW filter). Or you can do like I did and design my own GPS antenna that can survive all adjacent carrier interference you can throw at it.   Pete Weisskopf

[Bev & Billy on Sta-sea-dawn]

Thanks for the info...I will  read "Get Onboard with E-charting" by Mark and Diana Doyle.
I as this question because of an article I read in Cruising World Nov. 2013, "Computers on board".

The cruisers used an iPAD with Navionics Ap.  Another cruiser ran iNavX, Garmin Bluechart, and the Navionics programs....They were not more specific.

But they were out doing it, cruising....
Thanks again billy

[Bev & Billy on Sta-sea-dawn]

I know nothing about iPads....any idea of which make or model might work the best?...Billy

[PeteW]

The Chart plotter and Navigation software  I use is called Seaclear II . Download and install from here:

http://www.seaclear.net/

It's free and open source and  runs on any windows machine and I have also run it on Ubuntu Linux. Its a strait forward .exe executable.

You can download RNC maps from the NOAA website. Use the map_cal tool in the program file to auto load and  these files after you place them in the chart directory under the Seaclear directory in Program files. I'm still fooling around with the ENC files. I think they work right away without and conversion tool required. You can easily get almost 10,000 charts if you download the entire library from NOAA with updates available every 5 days.

You will need to wire the GPS NMEA  into a USB port to navigate. This might take wiring RS232 TX from your receiver into a USB serial adapter. Once that's going the software will display your coords automatically load the right chart as  you navigate. There are NMEA inputs for other device like your autopilot fluxgate compass and it will correct for magnetic deviation on the display based on position and info from the chart.

I'm putting together a ship computer with one of those Intel automotive fan less cpu blocks and some headrest LCD displays, all 12V. Or you can buy some old IBM 1.6 GHZ T40 Thinkpads for $100. Pretty rugged and plenty powerful enough for this stand alone operation.

[SailingSeaDragon]

Pete,

Thank you for the info... The letter writing campaign concerning the LightSquared licensing approval was led by BoatUs and other concerned groups some time ago. As for our Senator (I typed Congressman), you would need to live in Virginia to understand the mess we have - more importantly, the comment was not appropriate for this form - sorry.

Sailing the Chesapeake Bay we are all too aware of how easy it is to jam/spoof GPS signals. This happens often enough when sailing near nuclear power plants, low profile research facilities, and other odd locations...

Garner

[Bev & Billy on Sta-sea-dawn]

I am going to read and start my inquiry today...first at my local computer store...Walmart...Staples...Best Buy etc.
Ya'll have given me more than enough info to work on and digest.....I will keep this post...posted.  I have already purchased a mid grade GPS/nav system from WM, I have not installed it yet.  Now I am looking at the computer alternative.......Billy

[PeteW]

Garner,
I reviewed the information regarding LS^2 business plan and agree that ground station transmitters they are looking to install in the Inmarsat band will be GPS jammers. The Inmarsat transmitters in orbit are attenuated by an extra 50 dB so they do not interfere. The ones on aircraft point up.

So far it appears that the FCC has handled this properly and I doubt they will be intimidated by an LS^2 lawsuit. But even if they go away the next threat to GPS is just around the corner. UWB (ultra wide band) can't be detected, it just raises the noise floor.  That L-band spectrum is has become the battle ground for all things wireless. Back in 80's when GPS went on-line it wasn't like that. GPS does operate at other less congested frequencies but those are military secrets.

The situation can be improved with technology directed at the GPS receiver front-end specification but its unclear who should pay for that.  But I bet you would drop $50 for a high performance antenna if it mitigated the problem.

It looks like the best solution is to not count on the American GPS system into the future. It is intended primarily for military use and civilian access can be switched off. All development has been to only enhance its military use (GPS III).

The other GPS system that is very robust, thanks to Vladimir Putin, is the Russian GLONASS. You can buy receivers that are GPS +GLONASS that talk NMEA. Putin put  a tariff on imported cell phones that don't support GLO so US manufacturers are offering products. Garmin is behind the curve on having a GPS+GLO OEM module for there marine products which might be why there's trouble over at Boat US. Trimble which has been the leader in GPS technology has receivers that do L1 and L2 frequencies along with GLONASS which is FDMA. Buy using both networks in tandem very good precision and robust operation is being reported.

The European Space agency is close to having their Galileo network on line (GNSS). The US is concerned about this because it was originally designed to be more accurate than American GPS. Galileo is intended for civilian use only, so I'm looking forward that using that. There are already receives that support all 3 networks simultaneously.

Pete

[Dale Tanski]

Pete,

Thanks for the great information.  It would appear that all things are SNAFU.  Time to update my paper charts.

Dale

[INCOMMUNICADO]

Dale, Don't forget most of the U.S. paper industry has moved to South America.(unions, government regulations) Sorry I couldn't help myself. Allen

[Della and Dave]

Because I also fly airplanes, I have followed the whole light squared thing.  The company was sold that spectra, but their equipment, like all transmitters, has a little bleed over in frequency.  In addition, several of the GPS manufacturers made equipment that was somewhat sensitive to signals outside their range, and since light squared was transmitting at high power, a little bit of leakage when the adjacent frequency signal strength was very low, meant a big problem, when you were expecting the usual a few foot accuracy. 

Basically light squared was sold a small sandbox, and filled it to overflowing, Garmin was caught stealing sand from the other kids sandbox, and didn't like the taste and cried.  The FCC regulatory people were still stuffing pigeons into holes and didn't know the game had changed to sand.  Meanwhile Boris and Natasha were firing bottle rockets at the French, German and English kids that were fighting over how to put their sandbox together. 

Give me a paper chart and a star to steer her by........