Operation Manual IQ-MOTOR-eco GPS
11.2 Navigation
11.2.1 Reception quality of GPS
The GPS-receiver ca follow up to 20 satellites simultaneously. After switch-on of the unit, it is
necessary to have at least 4 satellites in reception in order to fix the position for the first time.
For the valid IGC-recording the instrument needs in any case reception of 4 satellites.
There is a table inside the receiver,
the Satellite-Almanach,
in which the path, place, and time
data of all satellites are kept with reference to the receiver.
The Almanac is continuously updated
during signal reception.
if the instrument is switched-off, the Almanac has to be re-established.
Normally the instrument recognizes its position under unobstructed view conditions after 2 minutes.
a few minutes. If the receiver is switched-off for a short time (less than 2 hrs.), the time for new position
If one is in movement, or if buildings, mountains or thick forest affect the reception of the receiver,
it may take some time.
Therefore, you should always look for the best possible visibility around you
and the antenna in the casing should point upwards if possible. Due to the fact that receiving strength
of the satellite signals is only approx. 1/1000 of mobile radios, these radio sets and other disruptive
factors (like notebooks) should be operated as far away as possible from the IQ-BASIC-GPS
.
The IQ-BASIC-GPS is fitted with a highly sensitive Sirf III 20-Kanal GPS-receiver,
which is featured
with lesser power consumption and also a significantly shorter satellite detection time.
Accuracy is between 7 to 40 m. As an average one may assume approx. 15 m.
11.2.2 Accuracy of GPS altitude
A good explanation on the GPS Altitude accuracy is found on the following website:
http://www.kowoma.de/en/gps/errors.htm
First of all the word accuracy has to be defined. On the website mentioned above you can
read: “The
declaration of the accuracy used by Garmin for their GPS receivers leads sometimes to confusion.
What does it mean if the receiver states an accuracy of 4 m? This readout refers
to the so-called 50 % CEP (Circular Error Probable). This means that 50 % of all measurements are
expected to be within a radius of 4 m. On the other hand, it also means that 50 % of all measured
positions are outside of this radius.
Assuming a norm repartition, 95 % of all measured positions are within a circle of twice this
radius, i.e. 8m and 98.9 % are within a circle of 2.55-fold of the radius, that is in this case within a
radius of 10 m.
