Garmin's GPS 18

Laptop GPS Receiver

November 5, 2005

(Added Information on NMEA Support for USB Version August 30, 2006)

Review By: Sam Penrod

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The GPS 18 is Garmin's product for use as a laptop GPS system, with auto-routing and voice directions.   It is a small, hockey puck type receiver with a cable, which must be connected to a laptop computer.  (Unfortunately, the computer is not included.)   The GPS 18 is operated by a Garmin software program known as nRoute.  This review should be used in conjunction with a review of nRoute which is available on and can be found here.

The GPS 18 comes in two forms, the GPS sensor with USB connection which transfers both data and powers the unit.  The other variation is a PC version which has a serial connection and is powered by a 12V cigarette lighter connection.  The package includes City Select mapping software with full unlock, (a 25 character unlock code for the GPS 18 is in the package) the software program nRoute and a windshield mount.  Street prices for the package is about $130. Check discount prices Click HERE.  The  GPS 18 seems to be Garmin's answer to Microsoft's Street and Trips and Delorme's Earthmate.  Garmin actually sells the GPS 18 package for less than it costs just to buy the City Select software on its own.  This seems to be a way to keep the GPS 18 competitive with other laptop GPS systems, which typically sell for a little over $100.   With City Select, and nRoute, you can input addresses, find points of interest (food, lodging, shopping, etc.) and then using the GPS 18, navigate to them, with voice directions.

The Unit

The GPS 18 is fairly small, about the same diameter as a can of Coke.  It includes a 12 channel receiver and is 
WAAS enabled.  Acquire times seem to be pretty good, in most cases less than a minute.  (Although the initial satellite acquire out of the box took about ten minutes.)  One thing the GPS 18 does not have is any type of display or even an LED indicator.  There is no way to tell if it is powered up or if it has a satellite lock.   A flashing LED for acquiring and a solid LED with a lock would be nice, but since its primary use is to be connected to a computer, it is not necessary.   The unit comes with an attached cable, either USB or serial which is six feet long.  The unit has a magnetic bottom and can be put on the hood or roof of a car.  You can attach the unit to the included windshield mount using the internal magnet or can attach it to the mount, using an included set screw.  The only way to get data from the GPS 18 is to connect it to a computer.
(Or in the case of the PC version, to an NMEA type device)

USB vs PC models


The USB version is probably the best model to buy, if your primary use of the GPS 18, is to use it for what it is designed for, as a laptop car navigator.  That way, there is only one connection required to the computer.  The USB version includes USB 2.0 interface and the unit is powered through the USB connection.  With the USB cable, you could easily add a standard USB extension cable as well, if you need more length.  As of July of 2006, Garmin added a free software download to make the USB version compatible with most non-Garmin GPS and mapping programs using the standard NMEA GPS language.  It is known as Spanner and according to 

You can download the Spanner software by following this link.

PC Version

The PC model includes both the serial port connector and the cigarette lighter adapter.  The cables merge into one cable, three feet from the unit, so there is only one cable going into the GPS receiver itself.  The PC model uses serial port with NMEA data, according to Garmin, the PC version is:
"asynchronous serial input compatible with RS-232 or TTL voltage levels, RS-232 polarity."  What this means is that yes, the PC model may be used to get out NMEA data.  For example, you can use it as a sensor to send lat/lon, altitude, speed, heading, etc.  I use the PC model as a GPS receiver for an amateur radio tracker, utilizing APRS technology.  The PC model is what you will need if you are dedicating an old laptop to be used with the GPS 18, if it does not have a USB connection.


Can I save waypoints and routes to the GPS 18?
Not to the unit itself, however with the use of nRoute, your waypoint, route and track data is stored for use in the program.  In other words, there are no files you open in nRoute like you would in MapSource.
The GPS 18 is only a receiver which will send data to a computer, although it is a functional self contained receiver.

Is the GPS 18 suitable for hiking or geocaching?

We would say no-- unless you want to pack along your laptop, which can be cumbersome and dangerous for the laptop.

Can you put the GPS 18 on the roof or outside of the car?
You can, it has a magnetic bottom which is strong enough for outside of a car.  However, because of the risk of theft, it is only recommended that you mount it outside temporarily and not permanently.

Other Observations

I actually purchased the GPS 18, for use with APRS, a ham radio GPS hobby .  But it did work as it is advertised with nRoute, as a car navigator laptop system.   I found mounting the windshield mount and then setting the actual receiver on it while I was using it, worked out the best.  Setting up the computer and inputting route information took more time, than just using a dedicated car navigator.  But again with the GPS 18, you are getting the same features of a StreetPilot type model, but at a fraction of the price.  What I will say about the 18, is that it is working very well with my APRS tracker.  The original GPS receiver I was using was a similar laptop type, however it had trouble getting a satellite lock, especially if the car started in a parking garage.  


The GPS 18 is a low expense car navigator, compared to the StreetPilot series.  It has most of the features and in some cases more, allowing for routes and track logs, satellite page, lat/lon, etc, which Garmin has cut out of the c3XX and new iX series.  However, because you have to use a laptop computer, the GPS 18 has some drawbacks.  It can be difficult and un-safe to operate while driving. The recommended use would be to have help in operating the system from a passenger.  The time of setting up the laptop and then powering it through an inverter will take more time and space, than a typical StreetPilot or other car navigator.  However, if you only use a navigator for family vacations or other trips where you need navigation help occasionally, the GPS 18 may be the way to go.  Again, more information about using the GPS 18 with nRoute can be found here.

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Email Sam Penrod