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Random Quote: Things are more like they are now than they ever have been.
W*hat kind of accuracy does anyone get with a GPS?* My Garmin 168 varies a lot, but I see Garmin has an add on reciever (GBR 21)*that is supposed to greatly improve the accuracy, has anyone had any experience, or heard about this.
I looked around, and the only GBR 21 I saw online was selling for $299.* This unit uses ground-based transmitters for differential correction, and gives 5-10 meter accuracy.* A WAAS GPS uses satellite-based differential correction, and gives 3 meter accuracy.* Unfortunately, according to the users manual, the 168 only outputs NMEA info, so I do not believe you can use WAAS.* According to Garmin, your present GPS has an average accuracy of 15 meters.*
__________________ PAX River, MD
Fisheye
Channel 69
I use a WAAS-enabled unit (Raymarine) and it is dead on - I would say it easily meets the 3 meter accuracy. For example, when sitting at the dock, I have measured with a tape measure at 40 feet to the end of the dock from my slip, and placing the cursor on screen at the end of the dock (shown by C-Map chip) the range to cursor displayed comes out right at 40 feet.
I've had similar experience with my 2006C.* WAAS rocks.* 3 meters works out to about 10 feet, and the repeatability of measuring the distance to my "slip" waypoint is almost always within 5 feet.*
Another story that impressed me was the experience of helping a buddy put a Raymarine system with WAAS on his new sportfisher with a flybridge.* We had to get the local electronics guru to help us get some of the wiring fished through the tubing, and he advised us to put the GPS antenna on the lower hardtop instead of the tip-top above the flybridge.* Why?* Because WAAS systems are accurate enough to*measure by the boat rocking back and forth, and being up at the very top would exagurate the rocking.*
Another story is that I've been able to sit very still with a WAAS handheld, and get zero velocity.* Literally just lean forward, and the GPS gave me a correct compass heading.* Sit still while leaned forward, velocity drops back to zero.* Sit straight up again, velocity vector spins around 180 degrees.* Just awesome.*
Check out the red line on the picture below.* That is the track from my 2006C when pulling my boat out.* Note that you can see which of the 3 available ramps I used.* The software I used to download the track and display it on an arial photo is ExpertGPS.* In the arial photo, you can also see a white shape where the dumpster sits I had to maneuver around just ahead of the boat ramp.
Note:* I have nothing to do with the company that produces ExpertGPS, I just think it's cool.
__________________ PAX River, MD
Fisheye
Channel 69
The 168 supports WAAS - but may require a firmware upgrade depending on what version your unit has. WAAS support was added in 2.60. Current firmware version is 3.50. If you have 2.60 or greater you can enable WAAS and enjoy the improved accuracy it offers.
Starting with version 2.6 of the software, the 168 gained WAAS capability, and there have been many bug-fixes since. What version is your 168 software? You can get 3.50 on the 168 Software Download Page.
GPS accuracy is one of those things that many really don't put enough importance on what it can be rather than what it is. It's no so much the accuracy but the integrity of that accuracy and there is nothing that will give you 100% confidence.
As for WAAS? well it's sort of interesting (not all that surprising though) that the FAA is trying to move forward in a more "cost-effective" way as WAAS simply comes at a huge cost for very little benefit. FAA has now revised its expectations of the system as it has been highlighted that WAAS will not be capable of providing Cat I performance at most the countries airports. Hence WAAS has taken a cut in funding.
"Fundamental problems with respect misjudging technological maturity" is also affecting other systems like LAAS as well as WAAS, simply not performing the task originally planned.
"WAAS simply comes at a huge cost for very little benefit"
Are you saying WAAS is unreliable in areas where it is available? I understand it is costly to provide it everywhere but once it is here, I assume it is very reliable.
I do agree that WAAS may not be the greatest thing to rely on for life critical decisions, but it works great for me when I'm looking to quickly locate underwater structure, or some such position-sensitive fishing measurement.*
__________________ PAX River, MD
Fisheye
Channel 69
Really WAAS started life in another era and then stagnated to not much more than a crawl and without the DoT actually pushing to partially declare it operational to any degree the FAA looked as if they really couldn't be bothered. I have this feeling the overall future of WAAS is completely up in the air and heading towards going downhill? Time will tell.
WAAS isn't going downhill or going anywhere in our lifetime. Kerry, stop scaring people and talk with some real frame of reference, you kow better...
The "too expensive" to be installed at other countries he's referring to is the cost of putting up billion dollar sattelites that broadcast the WAAS signals. NOT WAAS utilizing equipment. And third world contries will NEVER be able to afford the same high tech instrumentation that we enjoy.... has nothing to doe with WAAS in particular.
Now, it may be true that for AVIATION purposes WAAS is not as good as the FAA wanted it to be, but what does that have to do with boats that are traveling at a top rate of 35 knots in water with virtually nothing around them and 2 passangers. As opposed to a 747 with 575 passengers traveling at a rate of 600 MPH trying to land in the pitch dark between some mountains in Costa Rica (San Jose) at an elevation of 15,000 feet, sorrounded by building, other airplanes and weather!!!
Hasn't gone very far in the past many years either has it No, I'm not scaring people just being factual and in reality there is way too much hype with WAAS. Really the expenditure with WAAS to-date is the ground infrastructure as the WAAS corrections are currently transmitted using Inmarsat. If the FAA wanted to run their own Geo's then that would put the overall cost up even more and right now the WAAS geo's are the bottleneck in the whole system, no redunancy what so ever. If there was a real future in it then the $$'s would be forth coming. GPS cost to-date (over the past 25 years) around 12 billion, WAAS cost (over the past 7 years) around 5-6 billion, by design specifications GPS accuracy around 13 metres worldwide, WAAS accuracy around 7 metres and covers only a small world foot print, whats that around a billion $$'s a metre and where will WAAS be with civil dual freq in a few years at around 1.5 metres ??? and for only a billion or so more.
But then Galileo appears to have some influence on this funding cut decision as well but then galileo isn't here either.
WAAS also isn't absolutely required for 35 knots in open water with 2 passengers but really the reality check is homing in on the FAA and congress as technology is overtaking WAAS and similar systems like there's no tomorrow.
For landings WAAS was never really the intention as this was what LAAS's were supposed to do but even these have taken a backward step.
Gee even though Australia can't substantiate (being third world you know and all that ) WADGPS costs but then at least some countries have learnt things from WAAS/EGNOS etc and found ways around the prohibitive costs and did some lateral thinking and come up with systems that do the same thing but at a much reduced cost.
WAAS is not going away in the good old USA anytime soon. It is slightly better than anything we have and surely much better than anything most countries have.
The fear of losing LORAN C pushed many to GPS and guess what - LORAN is still up and running.
I have used LORAN C, GPS, and now WAAS enabled GPS. For repeatability WAAS rules but I will say that for 6 years running my old LORAN C had dead on numbers at it's berth in TDs. It was better than GPS when "the scramble" was still on and off.
GPS ACCURACY 
No, I'm not scaring people just being factual and in reality there is way too much hype with WAAS. Really the expenditure with WAAS to-date is the ground infrastructure as the WAAS corrections are currently transmitted using Inmarsat. If the FAA wanted to run their own Geo's then that would put the overall cost up even more and right now the WAAS geo's are the bottleneck in the whole system, no redunancy what so ever. If there was a real future in it then the $$'s would be forth coming. GPS cost to-date (over the past 25 years) around 12 billion, WAAS cost (over the past 7 years) around 5-6 billion, by design specifications GPS accuracy around 13 metres worldwide, WAAS accuracy around 7 metres and covers only a small world foot print, whats that around a billion $$'s a metre and where will WAAS be with civil dual freq in a few years at around 1.5 metres ??? and for only a billion or so more.
) WADGPS costs but then at least some countries have learnt things from WAAS/EGNOS etc and found ways around the prohibitive costs and did some lateral thinking and come up with systems that do the same thing but at a much reduced cost. 
