added instructions

and formatting

README.md

@@ -1,3 +1,45 @@
 # gps_spoofing
 
-How to fool your GPS enabled devices using Software Defined Radio, in this case using the HackRF One.
+How to fool your GPS enabled devices using Software Defined Radio, in this case using the HackRF One.
+This guide is written for Arch linux. But should be relatively consistent with other platforms.
+
+
+## installing
+you could build gps-sdr-sim from scratch, but I choose to use the binary provided by the 'blackarch' distro's repository.
+
+### Prerequisits
+
+```
+ $ curl -O https://blackarch.org/strap.sh  
+ $ chmod +x strap.sh
+ $ sudo ./strap.sh (installing the keyring step takes a few minutes)
+ $ sudo pacman -Syyu (update pacman sources etc. although stap.sh already seems to take care of this)
+ $ sudo pacman -S blackarch-radio (just install all the radio stuff (1Gb))
+ $ sudo modprobe hackrf (load the hackrf kernel module/driver)
+ $ hackrf_info  (see if you can see your hack rf one)
+```
+
+ Download the latest brdc file from here: ftp://cddis.gsfc.nasa.gov/gnss/data/daily 
+ (for example: ftp://cddis.gsfc.nasa.gov/gnss/data/daily/2020/brdc/brdc1460.20g.Z)
+
+ Extract the compressed file in a place you will remember
+
+### Generate location
+
+ Generate binary file to be transmitted by hackrf:
+
+```
+ $ gps-sdr-sim -b 8 -e ~/LOCATION_OF_YOUR_BRDC/brdc1460.20n -l 45.803304, 12.133697,100  
+```
+
+ The last part is the location of your choosing. This will run for 300 seconds and generate a 'gpssim.bin' file.
+
+### Spoof location
+
+ To transmit your spoofed gps position using the hackrf use the follwing command:
+
+```
+ $ hackrf_transfer -t ~/LOCATION_OF_YOUR_BIN_FILE/gpssim.bin -f 1575420000 -s 2600000 -a 1 -x 0 
+```
+
+ Enjoy!