Added info about nmea data to README

I thought it might be useful to add an explanation of NMEA 0183 and the different formats in which the data is transmitted to the microcontroller from the GPS. Only caveat is, I essentially plagiarized all of it. I did credit and link to where I got it from, but I'm not sure about the proper way to cite it is.

Author: evaherrada

README.rst

@@ -41,7 +41,7 @@ Feather boards and many other circuitpython boards will round to two decimal pla
     >>> float('1234.5678')
     1234.57
 
-This isn't ideal for gps data as this lowers the accuracty from 0.1m to 11m. 
+This isn't ideal for gps data as this lowers the accuracy from 0.1m to 11m. 
 
 This can be fixed by using string formatting when the gps data is outputted.
 
@@ -88,7 +88,69 @@ These two lines are the lines that actually solve the issue:
 
     print('Latitude: {0:.6f} degrees'.format(gps.latitude))
     print('Longitude: {0:.6f} degrees'.format(gps.longitude))
-
+   
+About NMEA Data
+===============
+This GPS module uses the NMEA 0183 protocol.
+
+This data is formatted by the GPS in one of two ways.
+
+The first of these is GGA. GGA has more or less everything you need.
+
+Here's an explanation of GGA:
+::
+                                                        11
+           1         2       3 4        5 6 7  8   9  10 |  12 13  14   15
+           |         |       | |        | | |  |   |   | |   | |   |    |
+    $--GGA,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x,xx,x.x,x.x,M,x.x,M,x.x,xxxx*hh
+
+
+1. Time (UTC)
+2. Latitude
+3. N or S (North or South)
+4. Longitude
+5. E or W (East or West)
+6. GPS Quality Indicator,
+
+   * 0 - fix not available,
+   * 1 - GPS fix,
+   * 2 - Differential GPS fix
+    
+7. Number of satellites in view, 00 - 12
+8. Horizontal Dilution of precision
+9. Antenna Altitude above/below mean-sea-level (geoid)
+10. Units of antenna altitude, meters
+11. Geoidal separation, the difference between the WGS-84 earth ellipsoid and mean-sea-level (geoid), "-" means mean-sea-level below ellipsoid
+12. Units of geoidal separation, meters
+13. Age of differential GPS data, time in seconds since last SC104 type 1 or 9 update, null field when DGPS is not used
+14. Differential reference station ID, 0000-1023
+15. Checksum
+
+The second of these is RMC. RMC is Reccomended Minimum Navigation Information.
+
+Here's an explanation of RMC:
+::
+                                                               12
+           1         2 3       4 5        6 7   8   9   10   11|
+           |         | |       | |        | |   |   |    |   | |
+    $--RMC,hhmmss.ss,A,llll.ll,a,yyyyy.yy,a,x.x,x.x,xxxx,x.x,a*hh
+
+1. Time (UTC)
+2. Status, V = Navigation receiver warning
+3. Latitude
+4. N or S
+5. Longitude
+6. E or W
+7. Speed over ground, knots
+8. Track made good, degrees true
+9. Date, ddmmyy
+10. Magnetic Variation, degrees
+11. E or W
+12. Checksum
+
+
+`Info about NMEA taken from here
+<https://www.tronico.fi/OH6NT/docs/NMEA0183.pdf/>`_.
 
 Contributing
 ============