WAAS

[BigDawg]

The default setting on my GPS 72 is WAAS DISABLE. Question...as a newbie...should I leave it there or enable it?

 

Keith T

[+EraSeek]

Your choice.

It will enhance your accuracy when enabled, given some time to load the almanac, with exposure to the WAAS satellite, but it is not a must. It will eat batteries a bit quicker. It is mostly a GeeWizz kind of thing for most of us. If you have good exposure to the sat, it can give you bouy bumping accuracy.

 

If you enable it, do it when you have good exposure to the horizon (in your case to the south east I believe). Watch for ''D's'' to start showing up on the sat strength bars. At first your EPE or accuracy reading may jump to high numbers, but then will start dropping down, maybe as low as 6' or 8'. Even though you are reading high numbers, you may still be getting the improved accuracy.

 

Most people turn it off to save batteries, and use it only for placing a cache or checking their unit against benchmarks, but some leave it on all the time. If WAAS is being used, it is working a bit harder to find those WAAS sats and to process the extra info.

 

[shrekTBA]

I have a Vista, and with it on, most of the time accuracy is 18 to 20 ft, with it off is still 18 to 20 feet. You have to be in the right spot to get it too work as the satillites are not in a good position to get the coverage, and the ground stations are only good if you are by them.

 

It's not a sport unless there is something dead in the back of the truck when you get home.

[lackdog]

I have read a lot about WAAS and heres a basic rundown:

 

-Yes it "can" improve accuracy

-It works better for marine applications or if your in wide open areas. If your in a forest or something with WAAS turned on or off you really won't see a differance in accuracy.

-Processor intensive functions such as auto route calculations will run considerably slower when WAAS is turned on.

-----------------------------------

 

WHAT IS WAAS

 

You've heard the term WAAS, seen it on packaging and ads for GARMIN products, maybe even know it stands for Wide Area Augmentation System. Okay, so what the heck is it? Basically, it's a system of satellites and ground stations that provide GPS signal corrections, giving you even better position accuracy. How much better? Try an average of up to five times better. A WAAS-capable receiver can give you a position accuracy of better than three meters, 95 percent of the time. And you don't have to purchase additional receiving equipment or pay service fees to utilize WAAS.

 

The origins of WAAS

 

The Federal Aviation Administration (FAA) and the Department of Transportation are developing the WAAS program for use in precision flight approaches. Currently, GPS alone does not meet the FAA's navigation requirements for accuracy, integrity and availability. WAAS corrects for GPS signal errors caused by ionospheric disturbances, timing and satellite orbit errors and provides vital integrity information regarding the health of each GPS satellite. Although WAAS has not yet been approved for aviation, the system is available for civilian use, such as for boaters and recreational GPS users.

 

How it Works

 

WAAS consists of approximately 25 ground reference stations positioned across the United States that monitor GPS satellite data. Two master stations, located on either coast, collect data from the reference stations and create a GPS correction message. This correction accounts for GPS satellite orbit and clock drift plus signal delays caused by the atmosphere and ionosphere. The corrected differential message is then broadcast through one of two geostationary satellites, or satellites with a fixed position over the equator. The information is compatible with the basic GPS signal structure, which means any WAAS-enabled GPS receiver can read the signal.

 

Who benefits from WAAS?

 

Currently, WAAS satellite coverage is only available in North America. There are no ground reference stations in South America, so even though GPS users there can receive WAAS, the signal has not been corrected and thus would not improve the accuracy of their unit. For some users in the U.S., the position of the satellites over the equator makes it difficult to receive the signals when trees or mountains obstruct the view of the horizon. WAAS signal reception is ideal for open land and marine applications. WAAS provides extended coverage both inland and offshore compared to the land-based DGPS (differential GPS) system. Another benefit of WAAS is that it does not require additional receiving equipment while DGPS does.

 

Other governments are developing similar satellite-based differential systems. In Asia, it's the Japanese Multi-Functional Satellite Augmentation System (MSAS), while Europe has the Euro Geostationary Navigation Overlay Service (EGNOS). Eventually, GPS users around the world will have access to precise position data using these and other compatible systems.

[+Renegade Knight]

Let me simply things.

 

WAAS is great for it's purpose but it slows down your GPS due to the overhead and doesn't help you in Geocaching enough to be worth the slowdown. Every geocacher I know who has WAAS on their GPS turns it off for geocaching.

 

Wherever you go there you are.

[+Criminal]

I was in FL over the weekend and the WAAS signals were incredible. I was looking at 8' error circles with my V's quad antenna and in the car with an outboard patch. Not much good up here in the Pacific NW but down there you can follow your GPSr right to the cache.

[+MedicP1]

I have a MAG315, and have gone through the manual and am unable to determine if I am "WAAS Enabled". I routinely have a 2-3M error reading, and see lock-on for either the #30 & #31 SATs on my screen (which I am told are the WAAS birds).

 

So therefore can I assume that I am "enabled", and then can I or how do I toggle on & off the WAAS birds?

 

GPSr's...A step in the right direction!

[robertlipe]

quote:

---

Originally posted by MedicP1:

I have a MAG315, and have gone through the manual and am unable to determine if I am "WAAS Enabled". I

---

 

The 315 doesn't do WAAS. Sorry.

[Kerry.]

The 315 is not WAAS capable.

 

The GPS satellites fit in the PRN# 1 to 32 slots and what is generally displayed on a receiver. These PRN#'s are (but can be the same #'s) generally different to the Satellite Vehicle Number (SVN) and the first of the "extra" satellites (such as WAAS and other systems) start at PRN#33.

 

Cheers, Kerry.

 

I never get lost everybody keeps telling me where to go

[+EtrexRose]

oops

[+apersson850]

It was due last Monday (16th), but is postponed until sometime in January now.

What is?

Preliminary transmission of "OK for test" status signal within the European EGNOS system. They are transmitting most of the time already, but with a "Don't use" status signal. Magellan receivers don't care about that the signal isn't reliable, they use it anyway. A Garmin receiver, however, refuses to use the signal until its status has been raised to the "OK for test" level.

 

They did try it on November 25th. I got the same EPE with six sats and EGNOS, as I later had with eleven sats and no EGNOS.

 

Anders

[+Poindexter]

The epe your gps gives you is not a true indicator of how accurate your fix is. It is just an estimation based primarily on satellite geometry. When SA was turned off the epe on Northstar 941X gpsr's did not change. They still show epe's of around 300ft. The programmers never changed the bogus algorithim that determined epe. They should do away with that feature. It only confuses people. If a gps new how much in error the position is, then why doesn't it just apply the correction? Because it doesn't really know how much in error it is, it just gives you a best guess. Which is useful to some degree but too many people take it as an absolute figure.

 

Poindexter

[+jollybgood]

Mostly because I'm too lazy to switch it on and off.

 

In Indiana I can usually get all "D"'s on the status bars since there is so much open space in rural hoosier land. I like having 8' accuracy showing on my screen even if it doesn't help find caches (since most cache placers don't use waas)

 

I've heard WAAS eats batteries and slows down the GPSr. I 've heard those claims enough that I really don't doubt they're true. But I certainly haven't noticed it enough on my GPSV to really give a hoot.

 

I've gone on 12 hour GPS hunts on the same set of batteries (rechargables). As long as it doesnt' drain my batteries while I'm hunting I'm happy.

 

Basically WAAS in an interested toy on my GPSr. If I didn't have it I probably wouldn't miss it.

 

Jolly R. Blackburn

http://kenzerco.com

[+jollybgood]

I think one of the reasons WAAS gets a bad rap is that a lot of users enable/disable WAAS to see if there is any diffence without giving WAAS a chance to kick in.

 

It can take up to 20 minutes for WAAS to start doing it's thing. When I start off on road trips it usually takes 10 minutes after powering up before the accuracy drops dramatically.

 

Jolly R. Blackburn

http://kenzerco.com

[+raouljan]

don't work very well together

 

>Personally Responsible for the Recovery of .00244% of the Benchmark Database!<--watch this number!