# 2. Applications

Now that you know how to recieve datas from the GPS,
let's see what you can actually do with them.

The main applications are the navigation solutions,
the data acquititions with spatial references and the geodesie.

These 3 main applications will lead to 3 reciever categories.

## 1. The navigation solutions

The receptor calculate your position x,y,z at a time t.
So if you move and you take your position at two different times
you typically have one vector. So the reciever can calculate :
- POSITION
- ALTITUDE
- SPEED
- TRIP (the trip that you have covered since a point that
you have fixed)
- TRACK (the direction you're following in comparison to the north)

Moreover, during the preparation of a trip, you can give your point of
arrival, and the reciever can calculate:

- bearing: the orientation in degrees to follow
- distance: distance to this point
- estimated time to arrival

If you have a winding trip, you just have to place enough waypoints.

All these parameters are very intersting in marine navigation and in plane.

Furthermore, you can now give maps to a lot of recievers, they will draw it in colors,
and place your waypoints on it.

That's why Navigation Systems are also very useful in a car, VTT, in the mountains...

At last, some recievers can remember your trips with the time between two waypoints. This
is a very intersting feature for transport companies.

Prices start from 200 euros.
## 2. Data acquisition with spatial references

They are based on the differential system (DGPS) and can be used to produce maps.

Prices start from 800 euros.
## 3. Geodesics

It's a lot more precise because it uses two frequencies, and thus costs very much
(up to 10 000 euros).

It has been used to measure the altitude of MontBlanc, or to monitor continents, zones with
high risks.

It can also be used to control art constructions like bridges.