Background Image moves up on keypad open and navigation

I have background Image for login which moves up when I open keypad to enter credentials and when I try to navigate to other screen.
CSS used: background: url($login-background);
background-size: cover;
background-position-x: 78%;
background-position-y: 100%;
background-repeat: initial;
for ion view and tried to fix the issue by setting height as hegiht of innerHeight but it doesn’t resolve issue while navigation
And it occurs only for android devices.
Kindly suggest how to proceed.