All of the vertical bars correspond to a satellite that the GPS is listening to. The numbers at the bottom refer to a specific satellite number. Here the GPS is listening to 2, 4, 5, 10, 12, 13, 17, 20, 23, and 30. Note that most of the bars are blue. On this GPS that means that the GPS is listening to that satellite and the information being received is good enough to be able to use in the calculation of your current position.
Sometimes you might see a “hollow” bar or a slot for a bar but no bar itself. This is the case with satellite #20. Data from that satellite is not being used to calculate your position. Taller bars indicate better data coming from that satellite. Number 30, 23, and 5 in this case are providing the best reception.
On the left side of the picture is a “map” of the satellites. Think of this as looking down at Earth (the big circle) with North at the top, and your current location centered in the circle. Now thinking of yourself centered in the middl, the outer circle represents the horizon, and the inner circle is looking up at an angle of about 45°.
Satellite #2 is to our West, a little bit North, and fairly high in the sky. (More than 45°.) Similarly, satellite number 4 is to the Northeast and also fairly high in the sky. Number 12 is just about 45° (half way from the horizon to vertical) and is to our Northwest. Number 20, which we are getting little to no reception from, is the furthest away, to the Northeast, and is just about on the horizon.
You can also see the current moon position in this view, and the current location of the sun which is about to set to the Southwest. There is also a little red dot which indicates our last calculated direction of travel.
