8.2.2 Degrees Decimal Minutes
Eg
3833.7072 N
12126.1950 W
GPS “raw data” use this format.
GPS antennae produce standard GPS NMEA sentences containing the
coordinate data. This data is then used by the GPS enabled device for
navigation or other location based services.
The standard for these sentences was developed by the National Marine
Electronics Association (NMEA), originally for marine applications.
8.2.3 Decimal Degrees
Eg.
38.561787
-121.436584
Decimal Degrees is perhaps the easiest way to understand GSP co-
ordinates. The Minutes and Seconds are simply represented by a decimal
fraction. The North / South and East / West markers are replaced by +ve
and –ve number notation.
8.3 Fixed Speed Cameras
There are many different types of fixed speed or red light camera systems
used around the world but, broadly speaking, there are 4 main technologies
used by fixed camera systems to measure the speed of passing vehicles.
•
Radar Camera systems like GATSOs use radar signals to measure
speed.
•
Inductive Loop Camera Systems like Redflex, Redspeed and
Traffiphot, are linked to inductive (electrical) coils buried under
the road surface which calculate speed based on the time taken
to travel over them.
•
Piezo Strip Camera Systems like Truvelo or DS2 are linked to
three sensor strips placed across the road surface which
calculate speed by timing how long it takes to drive over the
sensors.
•
Average Speed Camera Systems like SPECs or “GATSO point-
to-point” calculate a vehicle’s average speed between
fixed two points by recording a vehicle’s details at two
separate camera locations and working out how long
it has taken that vehicle to drive the known distance between
the cameras.
GPS warnings, as you approach potential accident locations where these
camera systems are sited, are a very effective safety tool to give advance
awareness of upcoming hazard areas.
For the most comprehensive guides on the internet, or to identify the
camera systems being used in your country, please visit the support
section of our website where you will find useful speed camera guides and
country guides.
8.4 Mobile Radar
Mobile radar camera systems are used in most countries with enforcement
programmes.
There are three main categories of mobile radar speed cameras.
•
Tripod mounted radar systems like Multanova and Mobile
GATSOs
•
Hand held radar guns
•
Vehicle mounted radar systems
GPS systems can provide reminders when you are approaching an area
where a radar system might have been used in the past, but they do not
tell you if a radar system is actually being used there now. GPS systems do
not “detect” anything - they simply provide a safety alert to remind you
that you are approaching a map location.
Radar Detectors are the only product which actually “detect” when mobile
radar enforcement is being carried out. There can be a huge difference
in performance between different brands of radar detector. The best
radar detector for your country may differ from another country because
performance can also vary against different types of radar cameras.
The GPS Mirror can integrate with a wide range of reliable radar detectors
from the leading brand manufacturers, but please note that the legality
of radar detectors can vary from country to country and it is your
responsibility to ensure that you comply with any local legislation.
15
