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What once was old is new again...
by Mark Sedenquist

In early 1994, we purchased and installed a GPS (Global Positioning Satellite) receiver in the Phoenix One. Built by the Magellan Corporation, the NAV 5000 DX has been our lifeline on more than a few occasions while navigating unfamiliar streets and back roads during our six-plus years on the road. Its off-road navigational capability, however, was of limited usefulness due to the "Selective Availability" feature mandated by the federal government. Starting in the mid-1980's, the government allowed two classes of GPS service. Military users could identify locations with an accuracy within 10 -20 meters, while the radio signals that civilian receivers used were degraded to a less than 100- meter accuracy. This was done to prevent criminals from using the signals to arm missiles and target US installations.

Civilian applications that needed a higher degree of accuracy, (e.g. aircraft) used a differential radio signal that required a near-constant data flow to reconfirm one's position. In our experience, when using the 3-D mode, (latitude, longitude & elevation), we often found the GPS receiver would pinpoint our location at a spot on the wrong ridge or at the incorrect elevation. Traveling off-road was truly an adventure if we relied too heavily on the GPS receiver to find our location. My personal favorite aspect of the technology was watching the receiver provide us with multiple locations in a fifteen minute time frame when the vehicle itself wasn't moving at all. Not a good situation if one is "lost" in a warren of logging roads in central Idaho.

Shortly after midnight on May 1st, the federal government ended the degraded signal and-- viola!-- the GPS in the Phoenix One became a nearly new device. Back in 1994, our GPS receiver, which is much heftier than the palm-sized devices now available, cost us about $900. These days, a variety of pocket-sized receivers with nifty features retail for about $150. Yesterday I ran some checks on our equipment, and I was happy to discover that it could pinpoint our location within about 50 feet-- a major improvement over the times when such accuracy was only a dream.

One of the products we like is the Magellan GSC-100 Global Satellite Communicator. This radio receiver uses the ORBCOMM- LEO (lower elliptical orbit) satellite network. The GSC-100 service has a $50 activation fee and costs about $30 per month. You can send and receive about 10 (500 character) e-mail messages each month. This may not be enough for normal e-mail usage, but it's great for getting messages in remote locations. Receiving accurate, location-specific, weather reports is another application. For more information about these devices, visit the 4x4 Books Web site.

The real value of the improvement in GPS service is the incredible market opportunity for telematic applications. In Road Wirer 16, I mentioned the FCC requirement for Electronic-911 service by 2004, but it is the enhanced possibilities for "mobile-commerce" that this enhanced GPS will provide that we should be watching. Earlier this month, the White House pegged the potential for m-commerce in the $8 billion range, and the ability to locate a specific consumer using GPS-based technologies is going to kick-start this business model. Already, some users of beta-version Palm Pilot products in certain markets are finding advertisements for specific goods and services appear on their screens when they near the locations of those businesses. ("Hungry? You'e only a block away from a Big Mac!") GPS and other locator technologies can be wonderful tools, but we should continue to exercise some prudent wisdom in the development and deployment of these new systems.

Mark Sedenquist
Austin, Texas
May 24, 2000