GPS Notes
On Other Pages
Various GPS units, mainly older. Using with U3S, disabling unwanted NMEA.
A cheap configurable, 0.25Hz to 10MHz GPS referenced generator. Good as a receiver/counter frequency check reference but NOT as an actual reference oscillator.
Using GPS reasonable accuracy may be achieved.
The use of GPS
Other maps/ satellite views
https://www.openstreetmap.org An open map, edit it, add house numbers in your locality and other features. Right click - "Show Address" gives coordinates and other information
https://www.street-view.net/where-am-i Lower resolution but gives location coordinates.
I wrote most belwmany years ago, most now will be familiar with Google and mobile phones but a little planning still helps. Google Maps and Street View will often locate your exact destination and give the exact coordinates in WGS84.
For critical navigation do not use GPS unless you are certain of what you are doing! The following are only my observations. For accuracy in conjunction with a map a GPS must be set to the same coordinate system to which the map was drawn. In the UK all the maps I have seen appear to be based on the Ordnance Survey. Therefore the GPS must be set to the OSGB grid and OSGB datum. This involves two settings on my Garmin Etrek. (For maps with a Lat/Long grid the datum should still be OSGB) I have noticed a discrepancy of around 200 yards (Metres) when my GPS was set to the WGS84 (Default) datum.
The GPS is a useful tool for navigating on land, while walking it keeps locked when in my shirt top pocket, except under heavy tree cover when holding up in my hand improves things. It will sometimes lock indoors when there is not too much above. Except when surrounded by lots of tall buildings it works well in the car under the windscreen. Modern SatNavs need to be used with care, some have been known to direct vehicles along unnavigable roads, look at a map! Current SatNavs have Lat/Long coordinate entry. I suspect this is WGS84.
An unknown destination may be reached with its help by keying in, or transferring from a computer, the coordinates or route. The coordinates may be found by looking at a map or if you know the postcode going to a site like http://www.streetmap.co.uk/ which will give a map and coordinates. Note that a location obtained like this is not precise. A postcode derived location can be perhaps half a mile out! Most GPS units may be used with a computer running an accessory mapping CD, which should make things very easy.