GPS tips and tricks

[Duane Scarborough]

Hey guys,

I recently purchased a refurbished Garmin 76 marine hand held GPS unit. This is a first for me. I understand the basics of how they work and all, but the nitty gritty of actually using it is tough.

But, I'm beginning to get used to it. I've been letting it ride back and forth to work with me for the past few days. I think that I've learned enough about how to use it now that maybe I could actually use it to get to work tomorrow if I had to. It's good that I allready know the way though, just in case.

I have learned so far that the speedometer in my truck is off by about 1.8 MPH, and the "almost straight line" to work that I've used for the past 10 years isn't nearly as straight as I thought.

Does anyone have any tips and tricks to share?

Duane

[Papee]

I use mine a lot. They are a handy tool once you catch on. Mine is on my iPhone so I can put in an address and it has a satellite view. I like marking all my fishing holes, I can take a photo of the area and attach it to that waypoint. Not much help to you though because mine has different features.

[Duane Scarborough]

Papee,

That sounds like a very cool feature. Mine is a pretty basic unit without many bells and whistles. Seems like they are all very different, even among brands.

But there's got to be some good general advice, tips, and tricks.

Thanks,

Duane

[Papee]

One thing I do use is when I set a waypoint then I start the nav to that waypoint and it will tell you how long you have (eta) traveling at the speed you are going. It will change eta as your speed changes. I find it handy to mark spots/waypoints that I go often.

[buster]

I don't know if I got a complicated GPS or if it's my low tech mind. I got mine mounted and wired. I also have reading the speedometer down pat! After scanning the manual several times, I still don't understand much more than that. It probably will dawn on me all at ounce someday

Dave

[Duane Scarborough]

Buster,

I think we both need a 10 year old to explain it to us.

Nah, I'll figure it out the hard way I guess. I've done fairly well so far. I guess it's good mine is hand held though, so I can ride around with it in the truck. I've learned just a little more each trip so far...

Duane

[Duane Scarborough]

Hey guys,

I thought that I had it figured out, but I guess that I still have more to learn....

This afternoon I went past HOME to pick up somthing at the store. As I was parking at the store, it beeped and displayed a message that I was approaching my destination.

I'd passed the street that I live on, (about 1/8 mile from HOME) and gone another 1/2 mile or so. Then it told me that I was almost there. Hmmm......

If I'd been in the boat in a dense fog, that could have been a real problem.

Once I got home, it told me I was there. The good thing was that it was still pointing toward HOME all of the time.

Another thing that I've noticed, I always park in the same spot (within a couple of feet) at HOME. Sometimes it says I'm within 15 feet of HOME, sometimes about 30 feet of HOME, and sometimes 100 feet of home. My usually parking spot doesn't vary more than about 5 feet at the most.

Not that it matters, but I thought they were more accurate than that.

But I'm still learning....

Duane

[Papee]

It may be just conditions. Mine will show the difference if I move around in the house from room to room. It can peg me within 2-3 feet. I used to look over my shoulder but now I look above. Mine also shows "tracks" going to a waypoint, if you go past or stray off course it will show the track going past the waypoint. What setting are you using it on?

Here's a pic of mine.Waypoint 1 is home and I took the long route to the normal boat ramp.

[Duane Scarborough]

Papee,

Like I've said, I'm still learning. There seems to be a differernce in how it interprets an approach distance. For example, am I approaching that point directly, or from an obtuse angle.

Today my normal parking spot was reported as being just 15' from HOME.

Part of that descrepancy may have to do with me not being consistant in how or where I lay it down in the truck. (in a cup holder, on the passenger seat, on the dash, etc.) It does seem to make some difference.

I think it's all about me getting used to it. It has never failed to point in the right direction.

Overall, I'm VERY happy with it. I've just got to figure out it's quirks. (or MINE)....

Thanks,

Duane

[Wildfowl]

They do take some gettinusedto... I started with them way back in the shoulder strap/pack days. Similar in comparison to a cellular bag phone.

I don't think they recognize obtouse approach angles...it's all linear equations and vectoring.

They will show you walking around the house or yard and that is cool....but if you try walking next to a previous plot trail you saved you will not be walking the "exact" trail when you go to folow the electronic version a day later. Close enough though...very close.

I think most are within 75' of accuracy.

The accuracy will change from day to day, hour to hour, even minute to minute. There is a built in degredation programed into the satelite feeds. Newer GPS will tell you what the current accuracy is if you find the right screen. You can also set them up with the optional WAS feed (or something like that) for greater accuracy.

The GPS system was built for and is maintained by the military. There was enough legitimate civilian use needs that they allowed feeds to the public. Keep in mind that this technology can go away in the blink of an eye as the military holds the switch to the feeds. That was a slow start for the electronics companies as they had to put in BIG BOLD WORDS that they sell RECEIVERS...they have no control over transmissions.

That being said here are a couple of the finer points of GPS:

The built in signal error is to keep someone from straping one on to a homemade rocket or unmaned aircraft.

Why did the government open the signal up to civilian use...to help us out right? Well... yes that... and to be able to track you. I may have shared this before but back in the seventies when the folks out in Berkeley were screaming about the "man" is going to be watching us. They were right.

The tracking is a good thing with services like onstar and cellular 911 calls. Yes your cell phone has a GPS tracking device in it. Your cell phone may not have a GPS receiver in it but it does have a tansmitter.

Now the good news is that I have recently used my GPS to find my way to the new job...Whooo Hooooo!

[brlcla]

I like reading how you newbies play with your GPS...

Accuracy is very dependent on conditions and satellite location... GPS basically works off of trigonometry.

If the Satellite is too close to directly above it wont give you a good position since the angle is so acute and visa versa the satellite wont give you a good position if it is too far to the horizon since the angle is so obtuse... That results in the majority of error that you see in handhelds... Also most handhelds work off of uncorrected signals which is basically due to the distortion of the earth atmosphere. So you will see a range of error. This is resolved by in survey grade GPS by using a reference station and the correction is based on mathematics between the two. Oh for those that dont know survey grade GPS has sub-centimeter accuracy...

GPS like previously mentioned is military controlled and for those that are intrested it was built to help track our submarines..."mobile missle stations"... Subs could pop up anywhere and knowing the GPS location would allow them to tell where they were and how to target the enemy.

If you have any friends in the surveying business ask them if the know the name "Trimble"... which is one of the smart bastards that discovered what the GPS system could do for the civilian world. It is some interesting reading if you look up the history of the GPS system.

[Duane Scarborough]

Wildfowl,

Thanks for that explaination. Glad you've got a job for it to help you find.

brlcla,

Thank you also for your insight. Glad I could give you a laff or 2 as well.

I am somwhat aware of the accuracy that the survey grade GPS units have. Mine was less than $100, so I sure don't expext it to have that kind of accuracy.

I'll Google Trimble sometime.... It should be interesting.

Thanks,

Duane

[Duane Scarborough]

Hey guys,

One of my work friends brought his Garmin 72 in to work today. I played with it a couple of minutes and decided that it's pretty much the same as my Garmin 76. "Great", I said, "now you can teach me the finer points of using it".

His reply was, "No, I thought you'd do that for ME."

Rats. I already had figured out more of the finer points than he had. And he's had his for about 5 years.

So much for that thought...

Doesn't really matter much. I've got enough of it figured out for it to be useful. I'll figure out the rest over time....

Thanks,

Duane

[chuckitt]

Hey Duane, don't those things come with an owners manual?
Chuck

[Duane Scarborough]

Hey Duane, don't those things come with an owners manual?
Chuck

Yeah Chuck, there is an owner's manual. But they take 5 pages to explain what could be explained in 1/2 page. The more I read, the more confused I get. And it's in really tiny print. I hate the manual.

Duane

[Papee]

We also speak English for the most part here.

[buster]

Duane,

So you got a manual like that too. It seems like they tell you everything except what you really want to know. Also, it seems to me they figure you already know how to use it and they are only pointing out the finer options.

Dave

[chuckitt]

Yea, I didn't like the manual either, I was trying to learn Diane's and teach her at the same time when i hit the language button and everything was where i could not read it. We had to get a friend to set it back to english. It's OK now that it don't speak a foreign Language.
Chuck