GPS Module (reading only GGA sentences from NMEA protocol)

Projects Networking, Protocols, and Devices
1

Hİ!

i have an external device can read only GGA sentences from GPS receiver module.if this device take other NMEA 0183 sentences(RMC,ZDA), it doesnt work. unfortunately my receiver module was broken. so i decided to use arduino with another GPS receiver.

my external device works with RS-422 Nmea protocol. so i have to use RS-422 to rs 232 converter and rs-232 to TTL. i filtered GGA sentences with arduino uno and then i will send to external device.

i researched on the internet and then i decided to use this code: Arduino: showing information from a GPS on a LCD

in this codes there are string.h and ctype.h libraries. how/from where can i find them?

if i finish this plan succesfully , i put here. if i didnt, my last plan is buying the GPS antenna which has rs-422 output with settable to GGA sentences.

thanks for all.