GPS antenna with linear polarization

Hello,

I know that GPS antenna works with a RHCP but I've found some others GPS antennas that use a linear polarization.

Can anybody explain that to me

I'm so confused now

thanks

Primary driven by simplicity, like compromise to fit in a cellphone.

You give up a little gain, but most importantly you lose much of the multipath reflection reduction. Reflections from building and other earthly objects reverses to mostly LHCP. Multipath rays can corrupt position accuracy.

Some studies argue the LHCP reflection reduction is overrated as vertical or horizontal metal strips of construction reflects as more linear polarization.

I've found that therocally we lost about 3 db if we use a linear polarization, have u any idea how can we calculate this?