Community Newsletter: Q&A: 11/3/06 I'm lost about what GPS unit I should get
- 11/2/06 5:41 PM
Which GPS system?
by Oldchris - 11/3/06 7:37 AM In reply to: 11/3/06 I'm lost about what GPS unit I should get by Lee Koo (ADMIN)
We have recently bought a Magellan 760, and we are very happy. Type in the street address, and away you go to the front door. No subscription prices. The screen voice warns you of a turn in 2 miles, .5 miles, and approaching turn, with a little bell to tell you that NOW is the time to turn. If you don't hear a little bell, go on to the next turn.
Garmin
by honutwo - 11/3/06 8:13 AM In reply to: 11/3/06 I'm lost about what GPS unit I should get by Lee Koo (ADMIN)
I have owned two Garmin GPS/PDA units, currently have an iQue M5. They are great when they work, both have been returned multiple times for repair.
Garmin's service department is poor, long waits for answers (don't ever try to contact them by phone)and I am required to pay the shipping to return the unit to them.
Why buy a second unit from them? Because of the accessories I have purchased. But never again!
I second that
by wresnick - 11/3/06 9:06 AM In reply to: Garmin by honutwoI don't know why anybody would post that their support is great. It's not the worst, but it's far from good.
When I first got my Garmin, it did not work. I checked their website, and it told me that due to the peak demands, it would take weeks to get back to me, and don't even think about calling them. Those weren't their words, but it was the essence. And it was already a month after the holiday season, so the peak should have been over.
I emailed them anyway, and in a few days I got a response. It was quicker than I expected, but was meaningless. It told me how to do a master reset, but that did nothing to help. I was going to return it, but I ended up speaking to somebody who is the head of support at another company, but who happens to know about Garmin products. He was able to tell me what I needed to know to get the unit working. I asked him why that was not in any manual or on-line help or FAQ and his diplomatic answer was a roundabout way of saying that their documentation is as bad as their support.
I did have occasion to contact them months later when the mounting disk came apart from its adhesive. They sent me a new one for free, no questions asked, and didn't ask for anything, which was a good, common sense approach. Many companies would ask for a receipt or ask you to send back the bad part, which helps little considering that it's of no use to them if they get it back, and a new one is of no use to me unless I have their product. So they got that one right, but overall, their support is below average.
But the saving grace is that their products should work out of the box. What they don't tell you is that despite what their instructions say, if you have a new unit and get no signal, you should leave it powered on, and in the open (or close to it, such as near the windshield), for at least 30 minutes, and it may work from then on.
Would I recommend it? Absolutely. I bought their low end unit for under $300, and it does quite a bit. My next unit was $50,000, but came with a free car, and did a lot more. Both units will be obsolete in a few years, but I'll be stuck with the one that's built into the car. Had I spent $800 instead of $300, I would have gotten a better unit. But if I wait 2-3 years and buy another $300 unit, it will probably do more than the $800 unit did that I passed on. In total, I will have spent less. With quickly evolving technology, going with the trailing edge and upgrading every few years gives you a better unit on average than buying the cutting edge and keeping it for a decade, and having an obsolete unit for 3/4 of that time.
satelite triva..regarding accuracy
by humin32 - 11/3/06 8:31 AM In reply to: 11/3/06 I'm lost about what GPS unit I should get by Lee Koo (ADMIN)
For accuracy your GPS reciever works best if it locks on to satelites that are at greater angles from it and each other. Since GPS satelites are in polar orbits the further north they go the closer they get to each other, the triangulation effect is lost. So, if you plan of going north of say the Artic Circle, the usefulness of will diminish.
20 years or so ago I worked doing precision navigational/positioning work on the north slope in Alaska as well as the Gulf of Mexico and California. For my purpose, the GPS was not accurate enough once you got north of the Arctic Circle. That may have changed by now?
I think back then they are short on satellites
by kschang - 11/3/06 9:23 AM In reply to: satelite triva..regarding accuracy by humin32From what I remember, back in the 80's the GPS coverage does NOT include the whole world, as not all of the satellites in the constellation have been launched yet. Some parts of the world have periodic "black-out" GPS periods where they cannot get sufficient GPS signals to triangulate. But that's back then.
Not entirely polar
by mggordon - 11/3/06 10:07 AM In reply to: satelite triva..regarding accuracy by humin32The satellites orbit at a high angle of crossing (the equator) but are not polar. That, combined with aurora borealis, can render GPS entirely unusable at the Arctic Circle (but, curiously, they can work to a certain extent north of that once you get out from under the Aurora). We had GPS on Navy aircraft at Iceland and sometimes they just didn't work very well at that latitude and directly under the Aurora.
Still, you can't beat GPS in a white-out. So what if you have a compass that points more-or-less northish? In much of Alaska, north is east 
Anyway, GPS tells you where you are, a compass tells you the direction to the magnetic north pole. Which do YOU think is more usefuL?
GPS Orbits
by Wheels76 - 11/4/06 8:00 AM In reply to: satelite triva..regarding accuracy by humin32The GPS constillation is inclined at 55 degrees, so none of the birds cross further north than that, which limit their usefullness at higher latitudes. Also, due to some recently discovered orbital path fluctuations there are 'holes' in the coverage (it shows up over Detroit, for instance, on a regular basis) so that can cause problems.
So, unlike TRANSIT's polar orbits, the GPS signal isn't projected well above 55N/S, and that causes problem in Alaska and other high-latitude areas. The Arctic circle, at 66.56 degrees north, is well above the normal coverage area.
WAAS up?
by dmmhelton - 11/3/06 8:40 AM In reply to: 11/3/06 I'm lost about what GPS unit I should get by Lee Koo (ADMIN)
I've haven't seen any mention of units with Wide Area Augmentation System (WAAS) capability. This is yet another feature that is becoming more prevalent in GPS electonics. This system was put into place by the Federal Aviation Administration (FAA)in 2001 to improve the accuracy and integrity (knowing when GPS is lying to you) for more precise landing guidance to runways. But we get to take advantage of it too.
GPS units with WAAS are no bigger, just slightly more expensive). They also drain batteries a little quicker due to higher processor demands. GPS reception is global, WAAS coverage is US only for now (Europe and east Asia in next few years). WAAS accuracy is not as good at the four extreme corners of the US, but the satellite signals are fine.
I'll save you the pain of explaining this system, but it does a number of things for you:
1) it increase accuracy from about an avg of 30 feet for normal GPS to an avg of 5 feet
2)it gives you at least one (if not two, eventually three) GPS satellites in view at all times (US only for now)
3)it tells you if GPS is lying to you...which it will do if one of the satellites begins transmiiting erroneous information (more a factor for east coast people).
4)it minimizes the effect of the DOD's Selective Availability (error inducing) system, but that probably a mute point since they don't use in the US and they could turn it up high enough to defeat WAAS.
Do you absolutely need it...no. But if you are using a GPS for finding places on foot or in a boat for fishing spots, it helps. In a car, it may provide someimprovement for reception and when there's a bad satellite, but 25 feet better accruacy probably doesn't do much for you.
Another receiver option I didn't see mentioned is using a PDA or PDA phone. You can buy a receiver/antenna to plug into them and load mapping software. You can generally find pkgs for between $80 and $130. Most PDAs now have speakers and headphone jacks for the voice prompts. Good solution if you already use a PDA or planned on getting one for other purposes.
I haven't use any of the car-specific units, but have used an older aviation handheld unit in my car (Garmin Pilot III) just for kicks. It had no detailed road maps or voice prompts. Based only on that experience, I would think it important to have voice command capabilities if you didn't have a able operator riding shotgun or didn't want to pull over everytime you wanted to change destinations or routes.
As others have said, decide what your primary use will be and buy for that use, with one exeption...if you plan to use for car navigation, make sure you can put street maps on it. You should also know that GPS does not work well in cities with high rise buildings or under dense tree cover. Heavy rain can have can drown a satellite or two, but that shouldn't cause any major problems. Ccontrary to another posting, clouds have no effect on GPS reception.
Just FYI...
by herr_howard - 11/3/06 12:48 PM In reply to: WAAS up? by dmmheltonThe Garmin Street Pilot series (i2, i3, i5) all have a WAAS mode and start at $219...not necessarily more expensive IMHO...
What type of GPS
by cburk35goal - 11/3/06 9:28 AM In reply to: 11/3/06 I'm lost about what GPS unit I should get by Lee Koo (ADMIN)
Recently bought a new car and purchased Garmin 550c with it. The garmin has nice features, like an FM based traffic system, which warns of traffic jams, and then can detour you around them. I live in the New York area, and this feature has come in very handy. Also, the Garmin has a blue tooth speaker phone, which allows hand free calling without the earphone. I have enjoyed these features enormously, especially when I compare them to my wife's Oem gps in a 2004 Lexus. By comparison the older gps, while still reliable, looks very outdated.
While there are many features on these systems, I think the phone is a significant improvement over the earphone and can make driving safer.
Navteq vs. Teleatlas
by daraghfi - 11/3/06 9:29 AM In reply to: 11/3/06 I'm lost about what GPS unit I should get by Lee Koo (ADMIN)
Anyone got a good comparison of the two? I know that Yahoo! and Google Maps use both tecnologies, but only Navman and TomTom use TeleAtlas in their units. I also believe that since TeleAtlas is also used by emergency services, it has better information on medical facilities (and more accurate addresses?). I don't know about POI (number and type) though...
D
Multipurpose GPS
by mggordon - 11/3/06 10:34 AM In reply to: 11/3/06 I'm lost about what GPS unit I should get by Lee Koo (ADMIN)
The Garmin 60CSx is very nearly a perfect all-purpose GPS. It is certainly true that you can choose from among many dozens of models, a blizzard of choices! It's expensive to have more than one (I have about six). I have long wanted just one GPS receiver I can take with me that serves both automotive routing AND offroad adventure. This one even includes barometric altimeter (good for weather guessing at camp) and a magnetic compass that rotates the map and provides a pointer even when holding still (most GPS lose their sense of "direction" when they are not moving). It includes very fine track logging capability which I have used to construct a detailed map of a Scout camp. You simply hike on the trails to every campsite, mark the campsite and name it. Then, load the track and waypoints into your MapSource program and viola, your hiking trails and campsites are superimposed on a topographic map. Very cool.
Still, if you do a lot of driving one of the Nuvi series would be better. I also have a pair of Garmin Rino 120's, each with topographic maps, two-way radio AND the kicker: you can SEE where the other person is on the map!
The huge memory capacity of the "x" series is obtained by a tiny memory chip that you place inside under the battery. It is really tiny, but can have up to about 1/2 gigabyte or maybe a full gigabyte.
So I have mine loaded with City Select routeable street map AND topographic maps; and I just turn on the map set that I wish to use at the time. So the very same GPS takes me via road to the mountains, I switch to Topographic mapping, and go camping, hiking or whatever.
The new receivers are supposedly more sensitive. They are certainly faster to lock. My Garmin GPS V lost its signal in dense forest in Washington State; the 60CSx supposely is more sensitive and when I get up that way I'll find out for sure.
Many people have made relatively harmless mistakes in these messages -- harmless because these errors do not alter your choice of GPS receiver. GPS is extremely complex and does not "simplify" very well. It is better to not try, I think. Some of the mistakes: "North Star" is really OnStar, "C Lorain" is really "LORAN C" and stands simply for "LOnge RAnge Navigation" (http://en.wikipedia.org/wiki/LORAN) and its precision was generally not very impressive. "2D" navigation requires 3 (not 2) satellites; 3D (lat/long/elevation) requires 4 satellites. In the northern hemisphere you need a SOUTHERN view to get most of the satellites.
Dependencies: You need 3 satellites and they cannot be in a line. If it isn't a "triangle" then you cannot triangulate. The only time I've ever been limited to only 3 satellites (or fewer!) was down in a canyon or under heavy forest.
Many GPS receivers display the DOP (Dilution of Precision), an indication of how accurate the measurement. Many comments have given accuracies that not even the manufacturers claim. Even with WAAS, 9 meter accuracy is about the best you can possibly get but geez people, that's INCREDIBLE.
WAAS
by dmmhelton - 11/3/06 12:43 PM In reply to: Multipurpose GPS by mggordonGood corrections, but I have to take some issue with your WAAS accuracy. The WAAS system is spec'd to give you no worse than 7m accuracy and actual system measurements have put it at 1.5m to 2m on avg.
I haven't used any of the WAAS capable handhelds so it is certainly possible that some of their implementations give you less accuracy. But the system does provide less than 9m accuracy unless they're messing with the system for some reason, e.g. moving a satellite.
GPS in the Arctic? will it work? which are recommended?
by muti1973 - 6/15/08 4:41 PM In reply to: Multipurpose GPS by mggordonI am going to Auyuittuq National Park in Baffin Island, Canada ( 80 10 W, 61 32 N )next month. I have purchased some good maps, but thought that it would be a good idea to have a GPS for both safety and fun. I have never used a GPS before and need some assistance.
I have read that there may be difficulties using it by the Arctic Circle and Aurora Borealis. Does anyone have experience? What are the limitations. Will I likely experience these where I am going?
If I get a GPS, I would like one that can work for trips like these: camping, trekking, outdoor stuff, and one that I can take with me in my car for road trips. Sounds like the voice activated ones are helpful? Are there other features, add-ons, softwares that are recommended? Can anyone offer a model that would be suitable? I would like to keep the price around $3-400.
Thanks in advance.
Still OK.
by R. Proffitt - 6/15/08 4:48 PM
In reply to: GPS in the Arctic? will it work? which are recommended? by muti1973
If you research this you find that high latitudes are considered 80 and up. http://findarticles.com/p/articles/mi_m0BPW/is_10_14/ai_110474814 There are plenty of these out there.
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