In a companion article, we reviewed 4 software options for turning Google Earth into a powerful moving map application using realtime GPS tracking. If you don’t own a GPS with compatible serial or USB interfaces, Garmin has two low-cost options that work not only with Google Earth, but also with most other PC-based mapping programs.

Garmin 18 PC

The least expensive option is the Garmin 18 PC. As the picture at right suggests, the Garmin 18 is an all-in-one GPS unit smaller than a hockey puck. The GPS has no external display - it simply outputs NMEA standard GPS messages over a serial cable anytime its plugged into 12V power. The GPS comes prewired with a 12V power adapter and DB-9 serial plug (found on most laptops). The NMEA serial interface is the most widely used ’standard’ for GPS communication - so this GPS should work with any software which claims serial GPS support (including all 4 Google Earth applications we reviewed). At just over $80, it is a low-cost way to GPS enable a laptop.

Garmin 18 USB Deluxe

The Garmin 18 USB Deluxe uses the same all-in-one GPS as the Garmin 18 PC, only with a single USB cable interface. The USB cable provides 5V power to the GPS (must be connected directly to the PC or on a powered USB hub) and provides the communication channel.

This GPS does not support the NMEA protocol. Instead it uses the Garmin Proprietary USB protocol. As such, the built-in GPS tracker in Google Earth Plus was the only software in our review with direct support for the Garmin 18 USB. The protocol limitation can be avoided through the use of ‘virtual serial port’ software such as GPSGate, a $30 program, which converts the Garmin USB messages to NMEA messages for use other programs. GPSGate also allows multiple programs to use a single GPS at the same time.

The Garmin 18 USB is available in a ‘deluxe’ package with includes Garmin City Select Navigation Software and nRoute which can provide real-time voice and map driving directions on your laptop. Pricing starts at about $130 for the deluxe package.

Which is Best

Since both units use the same core logic and antenna, neither has an advantage in terms of accuracy or performance. The Garmin 18 PC is less expensive, but also a bit less convenient as you have both power and data cables to manage. In the case of PC’s without a serial port, a USB GPS may be required. The USB GPS has the advantage of a single power/data cord, but requires extra software for compatibility with a lot of existing freeware GPS applications.

Other Options

DestinSharks Forum member bobmor99 suggested the Globalsat GPS SiRF Star 3 III Waterproof USB which is available for about $65.00. Unlike the Garmin 18 USB, it does not require additional software to communicate via the NMEA serial interface. We haven’t tried one ourselves, but the specs are impressive, as are the user reviews at Amazon.com.

Most modern handheld GPS devices support serial and/or USB protocols - and many even ship with the correct cables. In this case, you get a true standalone GPS for those times you don’t want to bother with the computer. The Garmin eTrex Legend can be had for about the cost of the Garmin 18 USB and does include a USB cable. For our favorite list of marine handheld GPS units, check out the GPS section of our Boating Store.

Related Posts:

Using Google Earth with a GPS - Real-time Position and Tracking Software Review

NOAA Wrecks and Obstructions in Google Earth

West Marine and Boat US Store Locations for Google Earth

Offshore Super Series Destin World Championship Google Earth Race Map

Google updates Google Earth 4 Beta with New Features on Nov 1st!

This entry was posted on Friday, January 5th, 2007 at 2:30 am and is filed under Boat Stuff, Maps & Charts, Boating Product Reviews, Google Earth Maps. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.