# What is modulo 2 pie phase?

What is modulo 2 pie phase? I am having trouble understanding this. Thanks.

I mean what is “wrapped” phase (which has a modulo 2 pie phase), and why unwrapping is necessary?
What exactly does a wrapped phase do?
(I am a beginner in InSAR and I tried looking into it, but I didn’t understand)

InSAR is based on the principle that not only the amplitude of the microwave can be exploited but also the phase.
While amplitude is the intensity of backscatter, phase tells about the position of the wave when hitting a target. This can only be measured in a periodic way and at best be described by a sine function.

source: https://slideplayer.com/slide/9522017/

If you compare the phase of two images, you get an interferogram that describes the distance to the sensor according to the different looking angles of the satellites. Because the phase is only measurable at the scale of the wavelength (for sentinel 0-5 cm), you need to unwrap, that is, to convert this cyclic information into a measurable metric units to sum up all phase cycles.

have you seen these materials?

Thank you so much. Never had I been explained so clearly. Thanks again