Summary

Now that you have some ideas about how the GPS signal carries information from the satellites to the receivers, you can delve into the errors that affect that information. The complete carrier phase observable equation can be stated as:

$$\varphi =\rho +d_{\rho }+c\left(dt-dT\right)+\lambda N-d_{ion}+d_{trop}+{\epsilon }_{m\varphi }+{\epsilon }_{\varphi }\text{ (carrier phase)}$$

On the left side of the equation is the complete raw range measurement from the satellite to the receiver. On the right side is the correct range between the two and several errors known as biases.

The next lesson will give you an idea of both the origins and magnitudes of those biases.