diff --git a/GPS-Sim.md b/GPS-Sim.md
index e2b5c0a..75cf238 100644
--- a/GPS-Sim.md
+++ b/GPS-Sim.md
@@ -1,9 +1,13 @@
-This app allows you to broadcast GPS baseband signal data streams. You can use [gps-sdr-sim](https://github.com/osqzss/gps-sdr-sim) to generate data for this app.  
+This app allows you to broadcast GPS baseband signal data streams. 
+
+## Generator
+You can use [gps-sdr-sim](https://github.com/osqzss/gps-sdr-sim) to generate data for this app.  
 
-## Example
 `gps-sdr-sim -e brdc3540.14n -l LAT,LONG,HEIGHT -o BBD_NNNN.C8`
+That will create `BBD_NNNN.C8`
 
-That will create `BBD_NNNN.C8` and then create `BBD_NNNN.TXT` with:
+### Sample rate and frequency specification
+Create `BBD_NNNN.TXT` with:
 ```
 sample_rate=2600000
 center_frequency=1575420000
@@ -11,5 +15,12 @@ center_frequency=1575420000
 
 Copy to your PortaPack MicroSD and open the file from the GPS Sim app.
 
+## Example
+We can create a realistic movement using a NMEA GGA stream generator like https://nmeagen.org/. In this website create several multi point lines with the positions you want. Download the NMEA file clicking "Generate NMEA file".
+
+`gps-sdr-sim.exe -e brdc3540.14n -g OUTPUT.nmea -d DURATION -o SOMEPLACE.B8`
+
+You also need to `SOMEPLACE.TXT` as specified above.
+
 ## References
 https://blog.csdn.net/shukebeta008/article/details/103270214
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