How do i increase gps speed refresh rate with “interpolated” speed?

Its not the 'libraries' that update once per second, thats just the the default output rate for most all GPSs.

If you want faster updates check the datasheet of the GPS for the instruction to send it.

You would also likley need to increase the baud rate of the GPS from the 9600 default and turn off most all sentences leaving only GPGGA and GPRMC.