Add A-GPS trick to GPS documentation

hardware/gps.md

@@ -63,7 +63,10 @@ Setup PPS for chrony
 ``` bash
 
 cat >> /boot/armbianEnv.txt <<EOF
-param_pps_pin=PA6
+# Orange Pi PC 2e PPS Pin
+# param_pps_pin=PA6
+# Pine64 PPS Pin
+# param_pps_pin=PH9
 
 EOF
 systemctl reboot
@@ -182,3 +185,69 @@ systemctl enable gpsconvert.timer
 systemctl start gpsconvert.timer
 
 ```
+
+## A-GPS
+
+This sets up a form of A-GPS to speed locks when indoors or having a hard time getting a lock in general.
+
+*This setup is specific to the Adafruit Ultimate GPS modules. You'll need to adapt this if using a different GPS receiver.*
+
+### Setup mt3339 utils and get latest sattelite hints
+
+``` bash
+
+apt install python-pip python-setuptools python-wheel python3-pip python3-setuptools python3-wheel geoip-bin
+pip install -U pyserial && pip3 install -U pyserial
+cd /opt
+git clone https://github.com/f5eng/mt3339-utils.git
+cd /opt/mt3339-utils
+./eporetrieve 
+
+```
+
+### Get your current ip address
+
+*Note: this MUST be done from your main internet connection, NOT VPN*
+
+``` bash
+
+curl http://ifconfig.co
+
+```
+
+### Setup Maxmind GeoIP database
+
+``` bash
+
+mkdir GeoLite2
+cd GeoLite2
+wget https://geolite.maxmind.com/download/geoip/database/GeoLite2-City.tar.gz
+tar -xzf GeoLite2-City.tar.gz
+cd ..
+
+```
+
+### Get IP Address Location
+
+```
+
+pip3 install -U maxminddb
+python3
+import maxminddb
+reader = maxminddb.open_database('./GeoLite2/GeoLite2-City_20190402/GeoLite2-City.mmdb')
+rec = reader.get('anipaddress')
+print('%s,%s,0' %(rec['location']['latitude'], rec['location']['longitude']))
+exit()
+
+```
+
+### Seed GPS Unit With Rough Location and System Time
+
+``` bash
+
+systemctl stop gpsd gpsd.socket gpsconvert.timer gpsconvert.service gps-logger
+./epoloader --speed 9600 --time - --location python_output ./MTK14.EPO /dev/ttyS2
+systemctl restart gpsd gpsd.socket gpsconvert.timer gpsconvert.service gps-logger
+
+```
+