Before you return the GPS you (hopefully) received this Christmas and wring the salesman’s neck because it “doesn’t work”, first read here.  Kevin Bolton*, GPS specialist, clears up some common GPS errors.

Problem 1:
The bloomin’ thing doesn’t work!

Solution:
Power to the people. Check the batteries. Have you inserted fresh batteries, or does your GPS have its own lithium ion battery?

If it’s the latter, see that it’s properly charged.

Make sure you use good quality batteries. Energizer Lithiums are good, or if you go for the more eco-friendly option of rechargeables, consider buying nickel-metal hydrides (NiMH) from a reliable brand such as GP Power Bank, Uniross or Energizer.

And avoid using acid batte-ries. They can leak, resulting in damage to you GPS.

Problem 2:
It’s on, but it’s not navigating properly!

Solution:
Pull it off. Have you removed the plastic protective film covering the screen? On many new GPS receivers this has a picture of a map display, which can be confusing if you don’t know that it’s only a picture.

Really? Check that the GPS hasn’t accidentally been set on demo mode. This setting simulates navigation and will definitely put you on the wrong track. To switch it off will differ from model to model, but generally if you press the “Menu” button, go to “Settings”, then to “System”, you should find the option to turn the simulation off.

Come in, satellite, come in. Does the GPS have a strong satellite signal? Remember that GPS receivers need line of sight to receive a strong signal, so they won’t work quite as well indoors, or in a restricted environment such as a narrow gorge or thick forest.

If you are using the unit in a vehicle, keep it above the dash so it has line of sight with the sky. And be aware that certain makes of vehicle (Renault and Volvo) may have a titanium sun filter in the glass of the windscreen, which may block the signal. In this case you will need to buy an external antenna (these cost around R300).

Problem 3:
Where is the @#$% place?

Solution:
Could it be Mongolia’s? Are you using the correct datum setting? A datum is the reference point from which a region or country was originally mapped.

There are numerous different datums around the world. It wasn’t a problem in the old days when you simply changed maps for different regions, but now with seamless GPS mapping covering the entire globe it can easily lead to confusion ... as well as a substantial error.

The international standard is WGS 84, the default on most GPS receivers, but sometimes you may wish to change to another setting, for example when using a map based on the Cape datum.

To change it differs from model to model, but if you press “Menu”, go to “Settings” and then “Units Setup”, you should find an option to select the datum.

hddd.dddd or hddd mm.mmm. Are you using the same coordinate format as your source document or friends?

In South Africa there is no set standard, which regularly leads to confusion.

The latitude and longitude system is commonly used, but be aware that this format can be displayed in a number of different ways: as degrees and decimals of degrees (hddd.ddddd); as degrees, minutes and decimals of minutes (hddd mm.mmm – the default in most GPS receivers); and lastly as degrees, minutes, seconds and decimals of seconds (hddd mm ss.s).

The same address can be indicated as follows: S25.84813 E28.17332 (degrees and deci-mals of degrees), S25 50.888 E28 10.399 (degrees, minutes and decimals of minutes) and S25 50 53.3 E28 10 24.0 (degrees, minutes, seconds and decimals of seconds).

No system is right or wrong. What is important is that you remain vigilant about which one you are using. To change it, go to “Menu”, then “Settings”, then “Units Setup” then scroll down to “Position Format”, and here you will be able choose the format you want to use. (This method will differ from model to model.)

Time out. Is your time set correctly for the region you are travelling through?
And don’t just find a reference that matches the local time.

For example, if you use a European capital that is in the same time zone as South Africa, it could confuse the GPS.

There is no South African time on GPS menus, so you need to go into the menu and manually set it (it’s normally two hours ahead of Greenwich, also known as “Bravo time”).

When you get stuck or are in doubt, press the “Menu” button and scroll down to get additional information.         

* Kevin is the owner of KJ Bolton Consultants ( 012 654 9813).