I'm currently working on a school project (near space gas balloon with altitude control mechanisms), which requires connecting a GPS sensor onto the control system built around Arduinos. From other people's recommendations as well as my good experiences with Garmin, I bought a Garmin GPS18x LVC (http://static.garmincdn.com/pumac/GPS18x_TechnicalSpecifications.pdf
). The GPS unit itself looks pretty cool, however with my beginner level on electronics, I'm having three major problems now:
1. According to online document (http://showcase.netins.net/web/wallio/GPSrcvrsvs60kft.htm
), GPS18 series sensor need to be updated to the newest firware (3.3 for now) in order to operate at above 60k ft altitude (this project will go that high). So I'm trying to connect the GPS to PC by soldering its wires into a DB-9 connector using the instruction on page 8 of its data sheet(why do they left the yellow cable that handles PPS open?). But the PC has no response after I connect the GPS unit onto it. I have the corresponding Garmin program installed on the PC though. I have no experience working with serial port on PC. Does anyone know what is going on?
2. For the requirement of this project, all the information we need to receive from this GPS sensor are just current time, current location, current speed, and current altitude. So for that, I think we just need to read $GPGGA sentences from the GPS. Am I right?
3. For connecting GPS18x LVC onto Arduino, because GPS18x uses RS-232 protocal, I think I need to convert this into TTL for Arduino using a MAX202 chip(I can only find MAX202 at school, but I mostly hear people using MAX232, is this ok?). After I have done that, can I directly connect the GPS in the same way as in this tutorial[ch65288]http://www.arduino.cc/playground/Tutorials/GPS
That are all my questions so far. I'm still a rookie on Arduino and welling to learn as much from you guys as I can. Let me appreciate in advance for any kinda help!