GPS & Navigation Gadget Central

Not the best technical source but some intriguing GPS-related accidents are described in the Mirror:

“SCOTLAND: In May, Scottish ambulance drivers were told to ignore their new £5m satnav system and use maps instead after drivers complained they were not being directed by the quickest route to 999 calls.

DEVON: The same month, a skip lorry driver’s satnav sparked rush-hour traffic chaos in Newton Abbot, Devon, after taking a wrong turn and getting stuck under a bridge.

WALES: Paula Ceely, 20, vowed never to listen to her satnav again after she was directed into the path of a speeding train at the Ffynnongain level crossing in Wales. The train slammed into her car, leaving the student within inches of her life. No one was hurt.

CORNWALL: A satnav was also blamed when a lorry driver took a wrong turn into a cul-de-sac in Wadebridge, Cornwall, in January last year. The driver left seven cars badly damaged when he performed a U-turn to correct himself.“

Technorati Tags:
Automotive GPS, GPS, GPS Receivers

Should GPS units not only tell you were to go but also help you avoid that bank holiday traffic. We think so and so does Navman. But has the company got it right with its latest GPS offering the iCN 550 with Traffic Pack bolt-on? We get on the road and test it out.

The next step in GPS is going to be providing traffic information to the driver on the move. With this information you will be able to re-route around accidents and travel hot-spots so you can get home quickly and safely.

It is a great idea and one that all the major GPS manufacturers are delevoping at the moment. Each has its own way of approaching and solving the problem. TomTom for example, offer a traffic service via the 700 series and to access it you have to connect a mobile phone via Bluetooth and dial in. Navman’s answer is very different however opting for a radio solution.

Bolt on what Navman call the TM550, and the device will happily tell you about any traffic incident in the country as it happens. If one of those incidents happens to be on your journey you can opt to be warned about it or automatically re-routed.

Warnings can be based on anything from slow moving traffic to a spot of fog on the road and depending on your own road preferences - i.e., do you prefer motorways to B roads - and the navigation system does a good job of re-routing to avoid the trouble.

As if by magic, even on our first test route the unit notified us of slow moving traffic and a accident on our route. Choosing to see what the device meant by slow moving traffic and happy to give up our time for you the Pocket-lint reader, we subsequently sat in a 45 minute traffic jam that we could have avoided. The second time this happened we weren’t so stupid, and after the warning of the accident opted to accept the re-routing option.

But how does the system know that there is trouble ahead? By tuning into its own built-in radio. The good news is that once you buy the iCN550 with the traffic bolt-on there is no further cost. No subscription charges and no hidden stealth taxes like having to phone in for the information. For once a company has launched a product with a lifetime subscription bundled in the initial cost. But it’s also where the first major disappointment comes in.

As we’ve mentioned, to work, the system tunes into the radio to get the latest traffic reports - in fact it actually uses the same service that your favourite radio station uses to get its traffic - hence how it can tell you every incident from John O’Groats to Penzance.

But achieving all this comes at a price and you have to have a horrible FM aerial strewn across your dashboard and suckered to your windscreen for the service to work. It is certainly not a fetching accessory to that plush car you were hoping to put it in.

Furthermore it requires a power source and a tangle of cables to work. In short it’s horrible and even in the words of Bud Smith, Global Product Manager at Navman, it is “Not pretty, but then we don’t expect this to be for the mainstream consumer”.

In today’s world everything needs to be for the mainstream consumer. I don’t want to spend £600 on a GPS system that is going to be difficult or complicated or blatantly looks horrid. I want something that I am not going to have to make excuses for whenever a colleague or friend gets in the car, and I certainly don’t want to have to justify to Mrs Pocket-lint that the reason I’ve covered the car in wires is so we miss the odd traffic jam when we go to the Mother-in-Law’s. It just doesn’t work like that.

Rant aside, the traffic element of the system works very well. Furthermore the actual unit is very easy to use and a vast improvement on Navman’s entry model - although at almost twice the price you would hope so.

Worthy bits to mention are a 3.5in touch screen colour display, the use of a 4Gb hard drive that comes preloaded with a complete map of Europe pre-installed and the introduction of a petrol and parking button that will tell you where the nearest of both are (independently of course) and if it’s the petrol station option you can even have the system add it to the route so you aren’t going off the beaten track.

The other option we liked was the ability to change the display from 2D to 3D to instructions and more on the press of a button rather than searching deep into the menu system.

Technorati Tags:
GPS, GPS Receivers, Navman

Here is a review of the Garmin Nuvi 760 GPS. A great little GPS unit!

Technorati Tags:
GPS, GPS Receivers, Garmin Nuvi

Here is a video review of the Tom Tom One XL Portable GPS. Highly recommended as I have one of these Tom Tom devices myself.

Technorati Tags:
GPS, GPS Receivers, Tom Tom

What features are important for a particular use are a very personal thing. And.. The features needed for hiking are a bit more extensive (and a bit different) from those needed for automobile navigation use. Below are my “essential hiking feature list” of GPS receiver features.

1) “Map” screen (as opposed to just a numerical lon/lat position fix): Makes it much easier to see where you are relative to reference waypoints.

2) WaterProofness: Unit should be rated submersible to protect it from getting wet.

3) Long battery life: Keeps you from having to carry so many batteries. Some units with 2 batteries have longer life than some with 4.

4) Built in Maps: Not absolutely essential, but big help in orientation and estimating distance to nearest roads. We now consider that any new GPS purchase should be one with mapping capability.

5) Route capability: Twenty Route capability is pretty standard, some have 50. Make sure you get one with at least 20 routes.

6) Waypoints: 500+ user entered waypoints are pretty standard, some can store many more. Make sure you get one that can store at least 500..

7) Multiple Datum capability is pretty standard: Make sure all the datums you will want to use are included in the GPS you select.
Fit nicely in your pocket and lightweight: This is a very personal thing, but you should consider it when you are thinking about hauling a unit around in the wilderness.

9) Bearing to next waypoint: Almost universal, but essential to hiking use.

10) Screen Size and your ability to read it are important especially if you have problems with viewing fine detail. B&W screens are fine for hiking and many color screens are hard to read in direct sunlight. TransReflective Color screens are the exception.

11) 12 channel parallel receiver system: Needed for best reception in difficult terrain and tree cover.

Not ABSOLUTELY essential features, but nice to have.

1) We recommend map memory of at least 20 megs for a mapping GPS. A minimum of 8 megs of map memory is recommended though you can “get by” with 1.4 megs or so if local topo maps for hiking maps are your only need.

2) Transreflective Color screens such as in the Garmin G-60C, G76C and Vista/Legend Color models and eXplorist models are easy to read in bright sunlight and are also reasonably easy on battery life when the screen backlight is turned on at night.

3) UTM and MGRS readout may be a consideration for some. This feature is available on a limited selection of consumer GPS receivers.

4) Topo Maps uploaded into your GPS: The Garmin USA Topo CD maps contain contour lines and small stream data very helpful in navigating in off-road territory. Magellan has a new TOPO map offering which is not quite as detailed as the Garmin offering.

5) For use under heavy tree cover or difficult (multipath) terrain conditions, an external amplified antenna will generally be helpful.

In no particular order, SOME of the current 12 channel parallel GPS receivers WE consider most suitable for hiking use include:

A) GPS receivers WITH the ability to upload maps into the GPS from optional proprietary maps:
Magellan Meridian (basic/gold/platinum)(^), Magellan Sportrak Pro(!), Magellan eXplorist 500, 600, XL(^@=), (Garmin GPS-60C(@&^)including CX models, GPS76CS(@&^), GPSMap76(@&%), GPS76C(@&^) including CX models, Vista Color(@!), Legend Color(@!) including CX versions, Vista (@!), Legend(@%) and Lowrance iFinder(=!#) (all models). The Magellan XL is physically larger than other units.

B) GPS receivers WITHOUT the ability to upload maps into the GPS:
Garmin GPS60, GPS76(&), G-12xl(@&#), G-12CX(&#), G-II+(&#), G-48(@&#), Venture(@), Magellan 315, 320

(**) The standard eTrex and eTrex Summit have a substantially reduced GPS feature set as compared with competitive models and while we think eTrex and Summit are “cute” and accurate enough in position measurement, Our opinion is that other models just slightly more expensive provide the needed feature mix for serious hiking activities. This comment does NOT apply to Venture, Legend, and Vista models.
(#) While these units are not “obsolete” from the standpoint of technology, newer units with more “features for the money” are recommended.
(&) Units which have a “standard” external amplified antenna port. (may be 2.5v or 5.0v power, check before buying antenna)
(@) Units which have the ability to calculate area (acreage) after you walk a closed loop.
(%) Units which have (only) our recommended minimum 8megs of user loadable map memory.
(!) Units with 19megs to 48 megs of non expandable map memory
(^) Units with 49megs or more map memory or with optional plug in memory modules.
(=) Units which are fully featured but which are more difficult to upload/download to than other units.

Units NOT suited to serious HIKING and GEOCACHING use due to being designed for other applications:
Garmin StreetPilot, ColorMap, StreetPilot III, StreetPilot 26XX(all models), iQue (all models), Magellan RoadMate(all models)
TomTom GO
Delorme EarthMate/SA9 system
Etak Skymap systems
Rand McNally Systems
(Any system requiring a laptop, palmtop, or ancillary computer device other than for data and map loading. A GPS receiver for hiking should stand alone in the field.)

Notes about GPS receivers for use in the woods:

1) eTrex models (due to their small size patch type antenna) have slightly less antenna gain and sensitivity and may not perform quite as well as others in difficult receiving conditions. They work just fine “out in the clear”.

2) Helix type antennas tend to get “detuned” and have lower sensitivity if the antenna is placed close to a metal surface. Some detuning can result if the antenna is placed in a pocket or in a knapsack with metallic items or your body in close proximity. Patch type antennas suffer less and work better if you want your GPS to receive with the unit close to your body or in your pocket. NO GPS will perform properly in these conditions unless it has an external antenna out in the clear. GPS receivers are DESIGNED to operate properly WITH A CLEAR SKY VIEW. Any time you compromise with less than a full sky view, you are compromising the operation of the GPS and the accuracy of your position fix.

3) There is NO GPS which can be trusted to perform at all times in heavy tree cover or in steep and narrow valleys where GPS satellite signal masking can be present. If one GPS performs today and another does not perform tomorrow in “identical” circumstances, it proves nothing without further testing. The GPS satellites MOVE continuously and today they may be in an excellent position and tomorrow when you test they may be in a quite poor visibility situation. Except for the eTrex models noted above, there is little difference in “in the woods” performance between the various models recommended. We did find that the Sportrak Pro models gave slightly better performance under tree cover than most models.

Technorati Tags:
GPS, GPS Receivers, Hiking GPS

What features are important for a particular use are a very personal thing. And.. The features needed for automobile navigation use are a bit different from those needed for hiking navigation use. Below are my “essential automotive navigation feature list” of GPS receiver features.

There are TWO types of GPS units for Car Navigation these days. First there are what I refer to as the TRUE CAR NAVIGATORS. These typically have large bright screens suitable for comfortable viewing at arms length on your car’s dashboard. They also provide VOICE GUIDANCE which I find I depend on more and more as I gain familiarity with GPS Car Navigation. The second models are what I refer to as HANDHELD CAR NAVIGATORS. These last models typically have a smaller screen, are battery or 12vdc powered, and they do NOT have voice guidance. Let us first examine the TRUE CAR NAVIGATORS.
First, lets think a bit about the FEATURES you will need in a GPS CAR NAVIGATOR.

1) Address to address Routing: All listed units now have this feature. In the following list, we omit manufacturing discontinued models. The automatic car navigation feature is now present in low and medium priced Garmin (such as all variants of GPS-60Cx, GPS76Cx, , StreetPilot (*) 2720/2820/7200/7500,c310/c320/c330/c510/c550 i2/i3/i5(*), GPS276C, GPS295, iQue(*), Quest(*), and NuVi(*) ) and the Magellan RoadMate 300/360/500/700/760/800/860 (*)/6000T/3000T/3050T/ 2000/2200, Sportrak Pro, GOLD and PLATINUM models. The Cobra NavOne 4500, TomTom icn750, and Lowrance iWay 500/350(*) also have these features. HANDHELD Models all require optional at extra cost mapping software for car navigation. The above models typically cost from $300 to about $1200 depending on model. Generally, more expensive units have more features, better operation, larger screens, brighter screens than the less expensive models. Note: While all OEM car navigators offer Address-to-Address routing, OEM Car Navigators typically are “reduced feature” models so as to be extremely simple to use. Most aftermarket units actually work better and have more functions than OEM models which cost much more.

Handheld Models: Garmin’s G60Cx/S, G76Cx/S, Vista/Legend (COLOR only) and the Magellan Meridian and Sportrak models all have optional address-to-address routing, but with “beep” prompting and no voice prompts.

2)Units providing VOICE PROMPTS for turns and guidance include: Garmin StreetPilot (all models), Nuvi (all models), Quest, Magellan RoadMate (all models), , TomTom 750, Cobra NavOne, Lowrance iWay (all) and many OEM automobile navigation systems. Delorme StreetAtlas 2006 and the Garmin nRoute system have good and economical implementations of address-to-address routing and can be used stand alone at reasonable cost IF you already have a laptop computer.

3) Built in road Maps: Built in and detailed road map displays of your area of interest are an essential feature of a good Automobile GPS receiver.

4) Route capability: Automatic Destination Routing is a standard feature on any good (modern) Car Navigator GPS.

5) Waypoints: Some Car Navigators use ONLY street addresses, road intersections, Points of Interest, Restaurants and such. This is a pretty good minimum requirement. Most Garmin models offer “mark waypoint” capability for locations and the ability to “point” to a desired destination on a map. We like this feature, but it is not essential.

6) Datums: Many (if not all now) Automobile Car Navigators have only WGS-84 datum. (-and they do not need anything else when they are loaded with ref datum WGS-84 maps.)

7) Mounting: Make sure the unit you select is capable of being mounted neatly and securely in/on your vehicle. Some mounts are flimsy, springy, and others are much more secure and stable. Check carefully.
Turn Here: Make sure the unit gives you the signal you want for a “next turn”. The best units have voice and visual prompts for turns.

9) 12 channel parallel receiver system: Needed for best reception in difficult terrain and tree cover. A 14 (and up) channel system is a good marketing tool, but brings little if any additional capability in real life operation. The new SiRF III and latest generation Garmin receivers do a great job in most any (but not all!) environments. City Canyons and steep mountainous areas can be a problem.

10) Dead Reckoning: Most of us do not drive often in high rise central city areas. If you do, you will want to consider units with a built in Gyro capability as the best GPS will loose lock in dense high rise areas. Garmin’s SP2650/2660 and the VDO Dayton are examples of these. With the latest high sensitivity receivers, this is not essential.

11) Maps: Make sure that the unit you select has user uploadable maps (or maps on its built in CDROM, CF card, MiniHD, or other memory) for the area you need. Also check the UPDATE COST and AVAILABILITY of map updates.

12) TrackBack and other “standard” handheld hiking GPS features are not generally available in Car Navigator units. When you think about it, “tracking back” the same way you came can be hazardous in a car navigator! (One way streets) These units are designed to generate a new route for you on each new destination selected.

13) The OEM car navigators are “engineered into the dash”, look great and perform the basic car guidance functions pretty reliably. However, these OEM units generally cost much more and offer inferior features and performance as compared with the Garmin StreetPilot and Magellan RoadMate units and other aftermarket equipment. We have had a number of reports of users unable to obtain map updates for OEM car navigation systems. Others have complained of the high cost of map updates for the OEM installed systems some as high as $600 for an update! We suggest you try and obtain a written guarantee of map updates for 5 years as a condition of buying an OEM car navigator. We suggest a discussion of the price of map updates is a good idea as well.

14) A very few GPS units have implemented a solution to “the traveling salesman problem”. Here you can input a series of addresses and the GPS will take you on “a” lowest time/distance route between the several destination. The Garmin StreetPilot 2720 and 2820 and are current examples of units with this capability.

Useful but not essential features:

1) An external amplified antenna can be useful to allow full sky view and maximum position accuracy for a GPS used in your car. BUT: Most modern GPS receivers work OK without one. Try without before you buy. If you think you might NEED this feature later in an RV, truck or similar, make sure to buy a unit with external antenna port.

2) Screen: A larger Screen than available on handhelds is a nice option. We think the Garmin i2/i3/i5/and Quest models are too small for comfortable routine automobile use. Color Screens are useful for getting more map information from the unit “in a glance”. Some models have “transreflective” screens and these models do better in bright sunlight than other screen types.

3) We think that “almost” everyone will want at least 2000 megs of map memory in a car navigator unless it will never be used on long trips. Almost all of the latest units meet this requirement Units with hard drives (as opposed to Flash memory) are almost always much slower at screen redraw and we now consider these obsolescent. We recommend units with either built in Flash RAM or with a CF/SD/SDmini or similar memory card. As examples: Sixty-four megs will hold the map of California or New York. It takes about 1200 MegaBytes to hold detailed road maps of the entire USA. 1450 Megabytes for Garmin’s 2610 for all USA and (available) Canada maps.

Selecting a TRUE CAR NAVIGATOR

Which GPS Car Navigator to buy can be a daunting task. There are a wide variety to choose from and the prices range from maybe US$150 to $4000. You can buy them already installed in cars or as an aftermarket item. Let me get my bias toward the OEM models out in the open here. Generally, I think OEM GPS car navigators are a) overly expensive, b) limited in features, c) very easy to use, d) have the great “built in” look that many prefer and e) (worst of all) map updates may be rare, non-existent or unreasonably expensive, and f) when you want to take the unit out of the car and it with you on a trip, it is not possible. It is for some of these reasons that Jack and Joe are partial to “aftermarket” GPS versions.

But WHICH aftermarket version? Well, we are going to try and help you with that decision here. Nothing is black and white about buying a GPS, same as your decision on which car to buy. There are a lot of options. Jack and I concentrate on functionality, flexibility, usability and how well the units generate routes and guide you on your way. Others may be just as interested in the cosmetics or “look” of the unit in their car which (in our analysis) is not considered at all. In the study below, we are not giving any advantage to either internal battery operated or (only) cigar lighter plug powered units. Car Navigators are generally NOT intended for hiking, marine or geocaching use, though a very few do have some limited ability in this area. We will mention any such limited hiking ability if appropriate.

IMPORTANT FEATURE QUESTIONS FOR YOUR “TRUE CAR NAVIGATOR” SELECTION

1) Is it reasonably easy and intuitive to input an address, select a Point of Interest (POI) such as a restaurant, hospital, garage or other destination?

2) Is the route generated by the unit “reasonable” and without major “quirks” and failures to direct you properly? We think this feature is all important in selecting a unit.

3) Does the unit have a sufficiently large and easy to read screen in all ambient light conditions you will encounter? This feature is extremely important and in a relatively dark store (compared with bright sunlight) you can choose a unit that is almost not readable on the dash of your car in bright sunlight. Without a reasonably easy to read screen under all light conditions, the utility of the instrument will be limited. Click HERE for some comparitive samples.

4) Is the mount provided with the system stable, easy to use, easy to adjust, and secure under ordinary driving conditions?

5) Is the visible route guidance on the screen easy to interpret, does the map show clearly where you are, and does it clearly show the streets in your immediate area so you can judge your actual position on the route.

6) Are the maps fully installed when you get the unit? If not, how easy/difficult is it to add or change maps when you drive to a different area? If you are able to load wide area maps into the unit does the Car Navigator automatically tie these different areas together or do you have to manually select a new map section as you move from one region to another?

7) What is the Quality and Accuracy of the maps provided? How often are they updated and at what price? Is there a mechanism to input changes to a GPS vendor and have maps updated in future updates?
Can I “mark” a location where I am and have the GPS keep up with such “waypoints” so I can return there later without again inputting an address? Can I NAME these locations with my own name? Some costly units do not have the ability to MARK a current location so you can easily go to it later.

9) Are there symbols available to designate WHAT a particular location is? (home, store, restaurant, hospital, etc.)

10) Am I able to make an external list of my waypoints and upload them to the Car Navigator?

The following are our comments on some of the more popular “aftermarket” car navigators available today. These are not all alike and a few have operational problems that we consider pretty severe. These are NOT necessarily in order of overall quality or desirability! We leave that selection for you! We are limiting our comments here to units we have reviewed and/or used extensively in the last 18 months. Units we have reviewed and our “very” brief comments follow. Units highlighted in RED are the units with our highest recommendation for overall performance and usability. The current production models that we have tested include: Garmin GPS-60Cx, GPS76Cx, , StreetPilot (*) 2720/2820/7200/7500,c310/c320/c330/c510/c550 i2/i3/i5(*), GPS276C, GPS295, iQue(*), Quest(*), and NuVi(*) for Motorcycles the ZUMO ) and the Magellan RoadMate 300/360/500/700/760/800/860 (*)/6000T/3000T/3050T/ 2000/2200, Sportrak Pro, GOLD and PLATINUM models. The Cobra NavOne 4500, TomTom icn750, and Lowrance iWay 500/350(*)The highlighed models offer superior screen readability in all lighting conditions, have frequently updated maps, are relatively easy to use but with about all of the features anyone would want in a car navigator. Garmin and Magellan models use NavTeq maps which are the best available today and they are updated about every 18 months or so. Generally all listed models are reasonably compact, reasonably lightweight and easy to transport on a trip. NuVi and Quest are reasonably shirt pocket sized. Most important of all is a unit’s ability to get reasonably optimum routes almost all the time. The later Garmin and Magellan units use the SiRF III and similar GPS receiver which provides excellent receiver performance in most conditions without and external antenna. These listed models are not perfect, but we think they offer (imperfect but generally very good) maps and routing throughout.

1) Garmin StreetPilot 2610/20/50/60> Though obsolete now, we consider these models the overall “performance standard” for today’s GPS car navigators in the area of consistently generating superior routes from A to B. We also think that the SP26×0 models have a superior feature set to any we have used including OEM models. Many of the later Garmin/Magellan/iWay/NavMan models DO have lots of fancy new MP3/BlueTooth/TalkingBook, and other neat features but, in our testing, none is better at generating an accurate route than the old SP26×0 units. However, most units come pretty close unless we note otherwise.

2) Magellan RoadMate 300/360/500/700/760/800/860 (*)/6000T/3000T/3050T/ 2000/2200> These models are right up there with the Garmin StreetPilot units in capabilities. Both Garmin and Magellan use NavTeq road maps which we think are the best available for the USA. The RM series is designed to have a simplified feature set and VERY easy to master user interface and is a bit more direct at address input than most. However, there are some useful navigation and GUI features missing that are available in other units. If you want a GPS car navigator for a “non-technical user”, this is a good unit to consider.

3) Garmin SP2720/SP2820/SP7200/SP7500/c320/c330/c340/i2/i3/i5/NuVi 200/300/NuVi 350/360/650/660/670/680/760/Quest/ZUMO> These units are Garmin’s entry in the “simplified and cheaper” mass GPS market. Some of these units have lower screen visibility in some light conditions than desirable, and on rare occasion has a little trouble routing properly but all it all, they work pretty well and are not a bad unit for the money. The less than adequate display brightness is the c320/c330/c340 unit’s major drawback.

4) Lowrance iWay 500/350> The iWay 350 has a bit smaller screen but the routing is vastly improved over that in the iWay 500 unit we reviewed. has perhaps the brightest and best looking display of the lot. It also has a built in MP3 player which we tried out and it seemed to work fine. The feature mix is generally good including a HD with USA/Canada NavTeq road maps included. However, it has some routing quirks that we feel are unacceptable for car navigators today. Even when driving on the freeway between Atlanta and Charlotte, the iWay repeatedly took us off the freeway, onto a country road for awhile and then put us back on the same freeway a few miles up the road. Sometimes it would just take us up the ramp, make us turn right or left and drive us a mile up the road and tell us to make a U-turn and get back on the freeway we had just exited. This is not good. Unfortunately, the unit’s propensity to generate strange and out of the way routes cause us to rate this unit NOT ACCEPTABLE. However, were Lowrance to provide fixes to the router software, we would probably rate this unit up with the SP2620 and RoadMate 700 in overall capability. Lowrance tells us that they are aware of this problem but have no immediate plans (as of May 2005) to provide a corrective update.

5) The Cobra NavOne 3000/4500> We will shortly have a review posted for the NavOne 4500. The NavOne 4500 is a vast improvement over the 3000 model. It gives generally consistent routing results and has a very capable feature set and a very extensive and generally accurate POI data set. Our first unit of the 4500 had a sample defect that “infrequently” would cause user data loss when power was disconnected or the power cable developed an intermittant connection at the cigar lighter. This problem is not evidenced in the second unit we received and Cobra appears to have corrected this problem in later production. The maps are of generally high quality and the route generation in the 4500 is generally good with some exceptions as noted in the review. It has a bright and very readable display in all light conditions. In the NavOne 3000 however, the rural area maps are quite out of date as of May 2005. City maps in the Atlanta Metro region by contrast appear to be quite accurate and up to date. This 3000 unit provides relatively good routing around Metro Atlanta but out in the country, routes are quite erratic and it gave us some pretty scenic (and out of the way) journeys as we followed it around rural North Georgia toward one or another destination. The unit seems to want to take you pretty far out of your way so as to be able to travel via a major highway. For the above reasons, we must rate the NavOne 3000 unit NOT ACCEPTABLE as of May 2005. Cobra tells us that they DO plan a software and map update to correct some of the above problems.

6) TomTom icn750> This is a pretty nicely performing unit with a display with a bit less contrast than the best but overall a good performer. The unit is quite compact and well designed. We rate the functionality and features of this unit as “good to very good”

7) Magellan RoadMate 760/800/860> We rate these units as “very good performers”. They have a great display, pretty good user interface, great NavTeq maps (but you have to zoom in to 0.2 mile scale to have any view of residential streets and minor roads and this is not adjustable), routing is excellent, address input easy and straightforward. My overall conclusion at this point is that this unit is one of the best for people who want good quality routing (not perfect every time mind you) and good quality at a moderate price, this is a good line to check out.
The Garmin QUEST/QUEST2 and NuVi 350/360/650/660/680/760 are really neat “shirt pocket” sized Car Navigators designed (we think) for the traveling salesman application. The original Quest unit has limited memory for a car navigator (fixed 128megs USA/256 megs elsewhere). The Quest 2 and NuVi models come with all USA and Canada maps loaded plus about 140megs(Quest 2) and 700 megs (NuVi 350) for other user maps. The color screen on the QUEST is bit small as car navigators go whereas the NuVi has a very nice and large screen. The 6xx and 7xx Nuvis have an even larger screen and all these models have very readable screens in sunlight. The later NuVi models have an edge in screen contrast and brightness. Both Quest and NuVi are flat and will fit comfortably into a shirt pocket. Overall, these units perform very well, gives good routes, have voice output of directions and a rather full set of Car Navigator features. They also have fair performance as a pedestrian navigator.

SELECTING A HANDHELD CAR NAVIGATOR> What features do you need?

The features you need in a handheld car navigator are essentially the same as for the above “True Car Navigators”. However, expect that the route generation and the map redraw speeds in the handheld models will be substantially slower than in the larger units with faster computers and more memory. Expect the smaller screen to be more difficult (even impossible) to read accurately at arm’s length on the dash. The “beep” alert tells you to consult the screen for the next turn but all the information about the turn comes from the screen display. We judge these are a little bit less safe to use than the models with larger screens and voice command output.

SOME of the HANDHELD GPS units we consider most suitable for automobile navigation include (in no particular order):

Meridian GOLD(@#+%), PLATINUM(@#+%), and Sportrak Pro(@~%) with DirectRoute, , iQue 3600 PDA/GPS (@#+), GPS76CS(@~+%), Garmin GPS-60C(@~+%), Vista/Legend COLOR(@^+%) .

Click on blue links above to visit our product review of a particular model.

Notes:(@) These units offer automatic address to address routing within the unit.

(^) These units offer fixed map memory in the range of 19megs to 32 megs.

(~) These units offer FIXED map memory size in the range of 50megs to 128megs.

(&) These units have optional memory module, 8 megs to 256 megs available.

(#) These units have available as option or standard, large memory to 2GB in form of fixed, CF or SD Memory plus a fast processor.

(=) These units have both a large map memory AND a CF or SD memory card.

(M) These models come with preinstalled maps for all USA and Canada and operate right out of the box.

(!) These more expensive units have either a Hard Drive, CDROM (or DVD) drive for map storage and a fast processor.

(+) These units have (or have as an option) an external antenna capability.

(%)These units have a smaller screen than some other models listed.

(>) We think these units are the best performers for Car Navigation purposes (though they may be quite limited in other applications).

Technorati Tags:
GPS, GPS Receivers, Automotive GPS

There are different types of GPS receivers. Before deciding which receiver to buy, you might consider a quick read of the following. This could eventually change your decision.

Type 1: Not-self-contained receivers (without screen), also known as RS232 receivers or also GPS mice. This type needs a computer (often a Pocket-PC or Palm PDA) and according program in order to visualize the actual position of the GPS receiver. The link between the GPS and the computer can be wireless (Bluetooth), by means of a cable or via a card-slot or sleeve. This type is often used for car-navigation systems with moving map on the computer screen and for golf GPS systems.

Type 2: Self-contained receivers (with screen). Here the computer is integrated in the GPS receiver. We have to distinguish between non-mapping devices (often handheld) and mapping devices which can be handheld or mounted in boat, car or plane (often with external antenna). This type sometimes has extra features as a barometer/altimeter, an electronic compass or even a radio transmitter/receiver.

Peter Roosen wrote a very nice interactive tool to help us choose a GPS receiver. Unfortunately it is in German, so we made a brief recapitulation in English. The program, NAVIG2, and the translation can be found here.

If your primary use will be in boating or aviation, you should look for a receiver for those particular fields, as they offer you some extra features and readings that will be missing on general purpose models. On the other hand will a good handheld marine GPS receiver serve you perfectly on land.

Type 3: The more sophisticated receivers for professional use in agriculture, mapping and GIS, military, oil and gas, public safety, survey etc. The principle of these receivers is the same as the above, but they often use extra receivers and special antennas for higher accuracy and can often store an enormous amount of in the field collected data, which can be treated later in the office.

Type 4: Dedicated single-purpose GPS systems as there are the car GPS systems with a build-in GPS receiver, using maps from the device manufacturer. Very useful for this purpose, especially because you can take the system from one vehicle to another without hassle. So you can even use it in a rented car or Jeep, during your holidays, contrary to the fixed in-vehicle GPS systems. You can only use maps of the device manufacturer and you can not upload your own maps. See our Car GPS page.

Here we also have to mention the stand-alone golf GPS systems, which show you where you are in relation to various targets on the golf-course of your choice. Most models in this category will not perform good (at all) as a classic GPS receiver. See also our Golf GPS page.

Type 5: Very special applications, using GPS, as there are vehicle tracking systems (See our GPS Car Tracking page) and child-locator devices (See our GPS Locators page). Both use a GPS-chip to measure their location and some form of wireless phone system to communicate this information over great distances, eventually via Internet.

Type 6: Phones with incorporated GPS receiver. They could already be used for in-car navigation with street maps coming in through the air. End May 2005 Sylvan Ascent Inc. launched TopoPhone, which provides outdoor recreation enthusiasts with a better GPS solution by turning a cell phone with built-in GPS into a complete Topographic mapping system. TopoPhone is superior to traditional GPS units, because it uses the phone to download maps automatically, and allows you to see where your friends and family are located. See also our GPS phones page.

Technorati Tags:
GPS, GPS Receivers

The Global Positioning System (GPS) is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense. GPS was originally intended for military applications, but in the 1980s, the government made the system available for civilian use. GPS works in any weather conditions, anywhere in the world, 24 hours a day. There are no subscription fees or setup charges to use GPS.

How it works

GPS satellites circle the earth twice a day in a very precise orbit and transmit signal information to earth. GPS receivers take this information and use triangulation to calculate the user’s exact location. Essentially, the GPS receiver compares the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away the satellite is. Now, with distance measurements from a few more satellites, the receiver can determine the user’s position and display it on the unit’s electronic map.

A GPS receiver must be locked on to the signal of at least three satellites to calculate a 2D position (latitude and longitude) and track movement. With four or more satellites in view, the receiver can determine the user’s 3D position (latitude, longitude and altitude). Once the user’s position has been determined, the GPS unit can calculate other information, such as speed, bearing, track, trip distance, distance to destination, sunrise and sunset time and more.

How accurate is GPS?

Today’s GPS receivers are extremely accurate, thanks to their parallel multi-channel design. Garmin’s 12 parallel channel receivers are quick to lock onto satellites when first turned on and they maintain strong locks, even in dense foliage or urban settings with tall buildings. Certain atmospheric factors and other sources of error can affect the accuracy of GPS receivers. Garmin® GPS receivers are accurate to within 15 meters on average.

Newer Garmin GPS receivers with WAAS (Wide Area Augmentation System) capability can improve accuracy to less than three meters on average. No additional equipment or fees are required to take advantage of WAAS. Users can also get better accuracy with Differential GPS (DGPS), which corrects GPS signals to within an average of three to five meters. The U.S. Coast Guard operates the most common DGPS correction service. This system consists of a network of towers that receive GPS signals and transmit a corrected signal by beacon transmitters. In order to get the corrected signal, users must have a differential beacon receiver and beacon antenna in addition to their GPS.

The GPS satellite system

The 24 satellites that make up the GPS space segment are orbiting the earth about 12,000 miles above us. They are constantly moving, making two complete orbits in less than 24 hours. These satellites are travelling at speeds of roughly 7,000 miles an hour.

GPS satellites are powered by solar energy. They have backup batteries onboard to keep them running in the event of a solar eclipse, when there’s no solar power. Small rocket boosters on each satellite keep them flying in the correct path.

Here are some other interesting facts about the GPS satellites (also called NAVSTAR, the official U.S. Department of Defense name for GPS):

* The first GPS satellite was launched in 1978.

* A full constellation of 24 satellites was achieved in 1994.

* Each satellite is built to last about 10 years. Replacements are constantly being built and launched into orbit.

* A GPS satellite weighs approximately 2,000 pounds and is about 17 feet across with the solar panels extended.

* Transmitter power is only 50 watts or less.

What’s the signal?

GPS satellites transmit two low power radio signals, designated L1 and L2. Civilian GPS uses the L1 frequency of 1575.42 MHz in the UHF band. The signals travel by line of sight, meaning they will pass through clouds, glass and plastic but will not go through most solid objects such as buildings and mountains.

A GPS signal contains three different bits of information — a pseudorandom code, ephemeris data and almanac data. The pseudorandom code is simply an I.D. code that identifies which satellite is transmitting information. You can view this number on your Garmin GPS unit’s satellite page, as it identifies which satellites it’s receiving.

Ephemeris data tells the GPS receiver where each GPS satellite should be at any time throughout the day. Each satellite transmits ephemeris data showing the orbital information for that satellite and for every other satellite in the system.

Almanac data, which is constantly transmitted by each satellite, contains important information about the status of the satellite (healthy or unhealthy), current date and time. This part of the signal is essential for determining a position.

Sources of GPS signal errors

Factors that can degrade the GPS signal and thus affect accuracy include the following:

* Ionosphere and troposphere delays — The satellite signal slows as it passes through the atmosphere. The GPS system uses a built-in model that calculates an average amount of delay to partially correct for this type of error.

* Signal multipath — This occurs when the GPS signal is reflected off objects such as tall buildings or large rock surfaces before it reaches the receiver. This increases the travel time of the signal, thereby causing errors.

* Receiver clock errors — A receiver’s built-in clock is not as accurate as the atomic clocks onboard the GPS satellites. Therefore, it may have very slight timing errors.

* Orbital errors — Also known as ephemeris errors, these are inaccuracies of the satellite’s reported location.

* Number of satellites visible — The more satellites a GPS receiver can “see,” the better the accuracy. Buildings, terrain, electronic interference, or sometimes even dense foliage can block signal reception, causing position errors or possibly no position reading at all. GPS units typically will not work indoors, underwater or underground.

* Satellite geometry/shading — This refers to the relative position of the satellites at any given time. Ideal satellite geometry exists when the satellites are located at wide angles relative to each other. Poor geometry results when the satellites are located in a line or in a tight grouping.

* Intentional degradation of the satellite signal — Selective Availability (SA) is an intentional degradation of the signal once imposed by the U.S. Department of Defense. SA was intended to prevent military adversaries from using the highly accurate GPS signals. The government turned off SA in May 2000, which significantly improved the accuracy of civilian GPS receivers.

Technorati Tags:
GPS, Satellite