Hib Halverson
Eight years ago, I published an article in Corvette Enthusiast magazine which compared automotive GPS receivers made by the three biggest players in the “portable navigation device” (PND) market. The winner was Garmin. Magellan finished second and TomTom third.
After the test, Magellan asked that we not return their sample so it remained in service. My Wife, the Fairest Sandra the Red, and I continued to use it on many road trips, including National Corvette Caravans in 2009 and 2014.
Lately, our trusty GPS sometimes showed us driving across undeveloped land. This happens when the map data base dates to before newly constructed roads. As this particular unit was no longer supported with map updates, it was time for a new GPS.
How GPS Works
The “Navigation Satellite with Timing and Ranging Global Positioning System” or “NAVSTAR GPS” and it is one of the all-to-rare government programs which paid-off handsomely for hundreds of millions of people in the United States and elsewhere in the World. Developed by the Defense Department in the late 1970s and early-’80s, GPS has been fully operational since 1994 and had the accuracy of its civilian-accessible signal upgraded in 2000.
The Global Positioning System uses a “constellation” of 32 satellites with 31 currently in use. Each is 12,600 miles high and orbits the Earth every 12 hours. The satellites are in six orbital planes. The amount of satellites per orbit plane is not uniform, an arrangement which improves reliability if multiple satellites were to fail. At any one time, six to nine satellites are visible from any point on the ground which is a significant redundancy beyond the four satellites needed for an accurate position.
Each satellite has an atomic clock accurate to one billionth (0.000000001) of a second and broadcasts a time signal which synchronizes with the other clocks. Each satellite beams microwave signals towards Earth. The signals travel at the speed of light, a constant 186,282 miles-per-second (983,568,960 ft/sec.), but even at light speed, it takes measurable time to reach the receiver which measures the time between transmission and reception, then multiplies that by the speed of light to derive the distance to the satellite. Let’s say the signal from Satellite 25 takes 0.0865-second to travel from the transmitter in space to the receiver in your Corvette. Doing the math, your car is 16113-mi., 2059-ft., ±15-ft. from that satellite.
Using a geometric process, “three-dimensional trilateration”, a GPS receiver calculates the distance to one satellite, which locates the device on a sphere on which every point is the same distance from the satellite. This process is repeated with at least two more satellites, then the GPS calculates where the three spheres intersect and that’s the receiver’s location. Doing this calculation with a fourth satellite, provides a more accurate position fix and provides altitude data.
Once the GPS “knows” its position, it applies that to mapping data it stores, then, displays location information to the user. To show a representation of a moving vehicle, to indicate speed and to figure arrival times, the receiver is constantly “trilaterating”, applying the results to its mapping software then updating its display.
Portable GPS Advantages
In ’09, when we tested the three GPSes, neither the iPhone–back then, it was either an original iPhone or a 3GS–nor its competitors had GPS chips. Today, there’s little question that smartphones have taken a bite out of the PND market. Nevertheless, I think, if one needs GPS in a car not equipped with a factory navigation system, a GPS receiver designed specifically for automotive use is a better choice. It has more to offer than a smartphone–larger display, for one. Also, there is more sophisticated navigation and guidance capability in a portable GPS and that improves the driver’s situational awareness on the road. I’ll even go as far to say that a good portable GPS may be better than some factory nav systems–the ones with lousy interfaces, map data bases which aren’t very good, those which are too expensive to update or cannot be updated at all.
Some phones which display location information are not really GPS receivers. They rely on multiple cell towers and WiFi hotspots to derive locations. When you use a “GPS app” like that, the positioning accuracy may not be as good. In many cases a real GPS is more accurate. In fact, they are typically accurate to within 15 feet.
Dedicated GPS receivers run off the car’s accessory socket. Thus, if you’re caught without a car charger and your phone has limited battery life, they are a better choice because, smartphone GPS apps are battery hogs. Do GPS with a smartphone and you’re also using cellular data because, since they don’t store map data, many phones have to go to the Internet for mapping. That’s no biggie if you have unlimited data but, if you are on limited data plan and you use GPS a lot, you’ll get zinged for going over your data limit.
What if you are in an area with no cellular service? With a smartphone you might be screwed. With a dedicated GPS unit, as long as you can see the sky and the device has power, it will give you location data. This is a key advantage because, if a time comes when you really need to know where you’re at–like if you’re lost driving in the middle of nowhere and your phone can’t get a signal–GPS is gong to find your sorry butt whereas all a cell phone will do is show you the “no service” message.
Say you miss a turn and the GPS has to recalculate your route. Dedicated devices do that quickly. With a smartphone, there may be a lot going on as far a processor load, such as receiving texts and playing music, while it’s, also, trying to trilaterate and display position data as well as going to the Internet for mapping. As a result, some time might pass before the phone recognizes you missed a turn and begins recalculate the route.
For all these reasons, even though I have an iPhone, I’m remain a fan of portable, GPS units.
Testing the DriveSmart 61
As Garmin was the winner of my 2009 shootout and, as the world leader in PNDs, the company remains the “big dog” in the handheld, automotive GPS market; I decided to order a Garmin “DriveSmart 61 LTM-S”. It’s a product which is priced right and has a set of key features I like: an “edge-to-edge” capacitive touch screen made of what Garmin spokesperson, Cesar Palacios, described as “…strengthened glass…”, free lifetime map updates and voice command capability. Other key technical aspects are 16-Gb of memory, a fast processor and the ability to accept an microSD card. The DriveSmart 61 is one of Garmin’s newest models having been rolled out in January 2017. According to Cesar Palacios, it’s become one of the company’s top sellers.
The standard mounting for a DriveSmart is a suction cup you stick on your windshield. I like to put it up high, just to the left of the rearview mirror. Extra cost options are Garmin’s “Portable Friction Mount” and “Air Vent Mount”, which allow other mounting locations when the windshield is not desirable.
First time I put the DriveSmart in one the Corvette Action Center’s test vehicles, I was smitten with its large, screen. Compared to what I used before, the DriveSmart 61 screen is a huge improvement: bright, sharp and with great color. This display is 6.9-in diagonally, more than half-an-inch bigger than what is, currently, the largest smart phone screen. The Garmin’s big screen does a better of displaying the graphical position data GPS users want. Its specifications are 1024×600-pixels and 170-ppi resolution.
This Garmin performs basic GPS functions such as routing, recalculation, showing gas station and food service locations, providing audible “turn-by-turn” directions and displaying time, speed and distance info very efficiently.
Two of our favorite features are: 1) “Active Lane Guidance” which, as you near some turns, exits, or interchanges, the DriveSmart goes to a split screen with the normal map on the left and a visual simulation of the road on the right on which a colored line shows the proper lane to be in and 2) how the device automatically zooms in when the route gets complicated and zooms out when the route stays on one road for a time. That said, one favorite feature we miss with this new GPS is Greta Garmin (we had to give Garmin’s famed female voice a name) repeating, anxiously, “Recalculating…recalculating…”
Some other cool DriveSmart tricks…
Say you can’t remember where your car is parked after a sold-out ball game. If you kept your GPS with you, you can use Garmin’s “Last Spot Go” feature to get back to your car in the stadium’s parking lot.
If you like to use “TripAdvisor” when you plan a road trip. The DriveSmart has a built-in TripAdvisor points-of-interest (POI) data base which is accessed via the “Categories” menu item.
Most automotive GPSes are capable of plotting routes which avoid toll roads, but the DriveSmart 61 can be set to avoid just about any road or point of interest. Say you despise having drive by your ex-girlfriend’s house every time you start a road trip which goes through her part of town. Well, you can program your DriveSmart to avoid “Ex Street”. If you want to stay out of her neighborhood all together, you can set the device to avoid that whole area.
The Garmin has voice command capability for GPS functions. In our tests, this feature worked very well. It easily recognizes commands spoken in a normal voice. Just for fun, we reconfigured the unit’s “wake-up phrase” from the default, “Voice Command” to “Hey Garmin”.
The DriveSmart can be configured to display traffic and parking information using Garmin’s “Smart Link” phone app. It also can display notifications your phone sends. All three of those features come from your phone via Bluetooth, so keep in mind, if you enable those functions your phone’s battery life will be affected and you’ll use your data plan to supply the content. If you want traffic data without using cellular data, you have to buy a Garmin “GTM 60™ HD Digital Traffic Receiver”. Finally, the default for the Smart Notifications feature is “select all” so, unless you configure Smart Notifications manually, expect to be deluged with notifications.
Shortly after I put the DriveSmart 61 LTM-S in service, Garmin released two different map upgrades, so I was soon to take advantage of the “Lifetime Free Update” feature. The process is simple: install the Garmin Express application on your PC or Mac, open the app and connect your device. From there, follow the directions on your screen. Doing updates this way is the best choice. The updates took a couple of hours.
Another nice feature of Garmin GPSes is they work with the company’s “BaseCamp” application which enables you to plan trips ahead of time on your computer then transfer that data to your GPS.
Shortcomings? The Garmin DriveSmart 61 has a few.
The biggest one is no “pedestrian” or “walking” mode. In the past, when visiting unfamiliar cities as a tourist, I have found a GPS with pedestrian mode to be quite valuable. We suspect that the DriveSmart 61’s short battery life–60 to 90-min.–might be one reason why Garmin discontinued the walking mode, but whatever drove its demise, we wish for that feature’s return.
Battery life can make Wi-Fi updates difficult. Combine a large update with slow Wi-Fi and the DriveSmart may die before the download finishes. You can connect the power cable to the car, but if the socket is hot only with the ignition on, a long download might be impractical. You can use an AC adapter, but then the situation gets complicated because Garmin does not make them. You have to go to a third-party supplier and, once you connect to an AC adapter, you’re asked if you want the file transfer mode used to update via the Garmin Express application running on a computer. Of course, you touch “No” because you want the update via Wi-Fi. Then, you see: “The attached cable cannot currently charge your device.” That means the AC adapter’s output is running the DriveSmart and no power is available to charge the battery. In this situation, while the Wi-Fi update takes place, the battery will not charge, but it won’t discharge, either. I think long Wi-Fi updates should be less complicated. Oh yeah…how do you charge the battery without power from the car? Connect the DriveSmart to a USB port then turn the device off. The battery will charge over a period of several hours.
The Garmin’s Bluetooth is said to add hands-free capability to a compatible mobile phone, however, the function is complex to enable, and when we got it working, the audio quality was average at best. Plus, the paired phone ends up not really “hands-free” because you have to make three selections on the Garmin’s touch screen to enable the “voice dial” function and, since you cannot end a call with a voice command, you have to make another touch screen selection on either the Garmin our your phone, to end a call. This “hands-free” capability is really not hands-free.
Bottom line. The DriveSmart 61 LTM-S is not perfect but it is a darn good GPS receiver with a lot of useful features and a reasonable price. It’s a great addition for any Corvette lacking a factory-installed nav system.
For more information visit https://buy.garmin.com/en-US/US/cOnTheRoad-cAutomotive-p1.html
