I'v seen different types of theese serial GPS.
The have been preset to 2400,4800,9600 og 57600 baud.
Then the GPS is connected, it starts sending out serial data every second. (plain ASCII-text)
The program prom previous reply is 100% working.
The problem must be in speed settings to the GPS or to Serial.window.
Speed in your serial windows (shown in lower right corner in an open windows) must be 115200, to
match "Serial.begin(115200)"
The GPS speed is a 'standard' serial speed (1200,2400,4800,9600,19200,57600,115200)