Mouse GPS receivers

GPS receivers that don’t have a display screen but connect to a computer with a serial or USB cable are often called mouse receivers because of their resemblance to a computer mouse. A mouse GPS receiver acts as an input device for a PDA or laptop and only sends satellite data that it’s currently receiving. Mouse GPS receivers are about half the size of the smallest handheld GPS receivers, but even so still have good satellite reception with open skies. Another advantage to a mouse GPS receiver is you can place it in an optimal spot on your car’s dashboard for satellite reception and then mount the PDA in the most visible place for driving. Depending on the model and type, a mouse GPS receiver can be powered by a cigarette lighter adapter, rechargeable batteries, or the device it’s plugged in to.
Although mouse GPS receivers are smaller than handheld GPS receivers, you still face the cable clutter issue, plus you can’t use the mouse receiver to get satellite data unless it’s connected to a PDA or laptop.
Some of the vendors of mouse GPS receivers (and their Web sites where you can get product information) include

DeLorme: www.delorme.com
Haicom: www.haicom.com.tw
Holux: www.holux.com
Mapopolis: www.mapopolis.com

Handheld GPS receivers

If your PDA has a serial port, you can easily interface the PDA to a general purpose, handheld GPS receiver.
Because you’re using the handheld GPS receiver exclusively as a data input source — and really don’t care about what’s appearing on its screen — just about any GPS receiver that can communicate with a computer via a serial port will fit the bill. You don’t need a lot of features and whistles and bells on the GPS receiver if you’re primarily using it this way. This option makes a lot of sense because the GPS receiver can be used independently of the PDA, especially outdoors during bad weather.
The primary disadvantage is that you have to contend with two electronic devices and the cable that connects them together. This can sometimes get a bit messy in a car, with hardware and power and interface cables scattered all over your dashboard. Also, this type of PDA navigation setup is a bit cumbersome to deal with if you’re walking around.
One of the best sources of GPS receiver interface cables for a wide variety of PDAs is Pc-Mobile. Check out its extensive product Web site at http://pc-mobile.net.

OtterBoxes

Although PDAs are relatively fragile and don’t get along well with water, you can find products on the market to protect them when exposed to harsh environments. Among my favorites are OtterBox cases. For a well-spent $20–25 for the lower-end models, these plastic containers defend a PDA or other electronic devices from Mother Nature as well as not-too-careful owners.
OtterBox has two products that let you operate a PDA (including using its stylus) while encased in a waterproof and crushproof housing. One model, the Armor 3600 shown in the figure here, has a waterproof portal that allows you to connect the PDA to an external GPS receiver with a serial cable. There are also accessories that accommodate the oversize external antennas of GPS receiver cards and sleeves. Tests performed by the U.S. Forest Service indicated no satellite signal degradation when GPS receivers were used in the Armor cases.
The Armor series of cases do add bulk to the size of your PDA. However, considering the protection that they offer, the rugged cases are well suited for anyone who wants to venture out into the wilds and use a PDA without worrying about it breaking. A 3600 Armor model will set you back about $100; OtterBox also has other Armor cases from $20–50.
I like to think of the OtterBox Armor products as accessories that turn your meek and mild PDA into a tough and rugged Humvee. To find out more about the products, check out www.otterbox.com

Interfacing Your PDA to a GPS Receiver

If you’ve decided that a PDA navigation system meets your needs (or maybe you just love cool high-tech toys), the first step is to decide how you’re going to use to get GPS data into your PDA. Options for doing so include

• Handheld GPS receivers connected to the PDA with a serial (or USB) cable.
• Mouse GPS receivers (a GPS receiver with no display screen and a serial or USB cable).
• GPS receivers built into PC or memory cards.
• GPS receiver sleeves (expansion devices that slide on the back of certain models of PDAs).
• Wireless GPS receivers that transmit data with Bluetooth radio signals.
• Integrated GPS receivers built directly into a PDA. I’m assuming you already have a PDA or are currently shopping for one and have a pretty good idea what you’re going to buy. Just keep in mind that most PDAs can be interfaced with a GPS receiver one way or another.

Look at the types of GPS receivers you can use with a PDA. Most of the GPS receivers designed for use with PDAs cost as much as low-end to mid-range handheld GPS receivers. Some also work with laptop computers, which provide the ultimate big-screen GPS display.

What are PDA disadvantages compared to regular GPS devices?

After reading through advantages of using a PDA as your navigation system of choice, you’re probably sold on a using a PDA. However, they definitely aren’t for everyone. Some of downsides include

• Ruggedness: Handheld GPS receivers are designed to take more abuse than PDAs, which often fail when they’re dropped or knocked around. Although you can buy ruggedized (with special enclosures that make them waterproof, drop-proof, bear-proof, and kid-proof) PDAs, they’re considerably more expensive than off-the-shelf models; expect to spend at least several hundred dollars more.
• Weather/water resistance: Unlike GPS receivers, PDAs aren’t designed to be waterproof or even weatherproof. This can be a major issue if you plan on using your PDA navigation system outdoors in damp, rainy, or snowy weather, you’re around water, or you have a leaky water bottle in your backpack.
• Power considerations: Most PDAs use internal batteries that are recharged through a docking cradle. If you’re away from a power source, this can be a serious issue because you can’t swap out dead or dying batteries for a convenient set of spare AA or AAA batteries like you can with a handheld GPS receiver.

When it comes to weighing the pros and cons of PDA navigation systems, you really have to examine your needs and planned use. If you plan on using a GPS receiver exclusively for road navigation, you should definitely consider a PDA. However if you’re going to be using GPS primarily in an outdoor setting, you’re probably better off with a handheld GPS receiver. If you’re leaning toward a PDA navigation system (or already have one) and want to operate it out in the elements, at least buy an OtterBox or some type of protective bag. I guarantee that your repair and replacement bills will be considerably less compared with stowing your PDA in a jacket pocket.

What are PDA advantages compared to regular GPS receiver?

Aside from being cool, a PDA might make sense for you as part of a personal navigation system for a number of reasons. Some of the advantages include

• Larger screens: PDAs have larger, higher-resolution, color screens compared with handheld GPS receivers. This is a big plus if your eyesight isn’t as good as it used to be — and it’s really important if you’re using the PDA while driving. You want to be able to quickly glance at a map on the screen, determine your location, and then get your eyes back on the road.
• More maps: Most of the maps that you can upload to GPS receivers don’t have a lot of detail; especially the topographic maps. These maps tend to be vector line maps and don’t have the resolution or detail found on paper maps that you’d use for hiking. Several mapping programs are available for PDAs that support all types of maps, and you can even create your own custom maps. With a PDA, you can use more detailed maps, like scanned, color 1:24,000 topographic maps. Bonus: You’re not locked in to using only a GPS receiver manufacturer’s proprietary software and maps.
• Expandable memory: Unlike many GPS receivers, which have fixed amounts of memory, most PDAs support expandable memory with plug-in memory cards. The only limitation to the number of the maps and amount of data that you can store is the size of the memory card.
• Usability: Although handheld GPS receivers are fairly easy to use, the user interfaces found on PDAs are even simpler. Using a touch screen and stylus to enter data and commands is a lot faster and easier than using the buttons on a handheld GPS receiver.
• Custom programs: Developers can easily write custom programs for PDAs that access the data output from a GPS receiver. If you’re collecting information that’s based on location data, this can make your job much easier than pressing buttons on a GPS receiver and then handwriting remarks in a field notebook.
• PDA features: PDAs have all sorts of useful programs such as address books, contact lists, and databases designed for readily storing data. A fair amount of this information tends to be location based (like addresses), and having a single information/navigation device is the definition of practical.

Choosing between a GPS Receiver and a PDA

Personal digital assistants (PDAs), such as a Pocket PC or Palm, are a popular way of accessing GPS information. The PDA processes satellite data from a GPS receiver and then displays your current location in a mapping program.
You can use many different types of GPS receivers with PDAs, including handheld, mouse, wireless, and card. This chapter helps you navigate through the PDA/GPS maze by reviewing the different hardware and software options and comparing common, handheld GPS receivers with PDAs that use GPS. I start things off by discussing some of the advantages and disadvantages of PDA-based navigation systems. You might wonder why anyone would you want to use a PDA instead of a handheld, consumer GPS receiver. That’s a very good question; you gadget junkies out there who have your hands raised and are answering, “Because it’s cool,” please put your hands down and continue reading. You’ll find compelling advantages and disadvantages to using a PDA with GPS that are based on your intended use and needs. To see whether you should even be considering a PDA navigation system, review some of the pros and cons right from the start.

Virtual GPS

Lowrance (www.lowrance.com) has a unique series of simulators for its sonar and GPS products that run on your computer. Just download and run a program from the Internet, and a lifelike replica of the product appears onscreen. The GPS receiver simulators don’t actually track satellites, but other than that, work just like the real thing. Use your mouse to click buttons, and the keyboard arrow and Enter keys to select menu items and change settings.

Although Lowrance designed the simulators as a way for potential customers to become familiar with their products (and for owners to practice with them), GPS receiver simulators are an excellent way to find out about concepts and functions that are common to all GPS receivers, no matter what the brand or model. The user interface and features vary between brands and models, but key GPS receiver concepts such as datums, coordinate systems, waypoints, routes, and tracks remain the same. The Lowrance simulator, shown in the figure here, lets you come up to speed on basic GPS receiver operations without even owning a receiver; plus it’s fun to play with. (If you download a simulator, get a copy of the real product’s user manual so you can understand and try all the features. These can be downloaded from the Lowrance site as well.)

To download Lowrance simulators, go to
www.lowrance.com/software/pcsoftware/demos.asp.