Hi I am new to this field and need your help on this.
I want to get the GNSS Ephemeris Data in Android. I don’t want to download it from any website.
This is what I am doing currently:
I am logging the GNSS Navigation Message on Android using GnssNavigationMessage.java (https://android.googlesource.com/platform/frameworks/base/+/refs/heads/master/location/java/android/location/GnssNavigationMessage.java).
In my logger I am getting the data using the command:
byte data = navigationMessage.getData();
Now the data I am getting looks like this:
Nav,103,769,1,2,1,8,16,-4,19,66,-112,-126,-42,25,20,-8 which follows a header
I want to get the following parameters for further calculation:
- PRN % SV PRN number
- Toc % Time of clock (seconds)
- af0 % SV clock bias (seconds)
- af1 % SV clock drift (sec/sec)
- af2 % SV clock drift rate (sec/sec2)
- IODE % Issue of data, ephemeris
- Crs % Sine harmonic correction to orbit radius (meters)
- Delta_n % Mean motion difference from computed value (radians/sec)
- M0 % Mean anomaly at reference time (radians)
- Cuc % Cosine harmonic correction to argument of lat (radians)
- e % Eccentricity (dimensionless)
- Cus % Sine harmonic correction to argument of latitude
- Asqrt % Square root of semi-major axis (meters^1/2)
- Toe % Reference time of ephemeris (seconds)
- Cic % Sine harmonic correction to angle of inclination
- OMEGA % Longitude of ascending node at weekly epoch (radians)
- Cis % Sine harmonic correction to angle of inclination
- i0 % Inclination angle at reference time (radians)
- Crc % Cosine harmonic correction to the orbit radius
- omega % Argument of perigee (radians)
- OMEGA_DOT% Rate of right ascension (radians/sec)
- IDOT % Rate of inclination angle (radians/sec)
- codeL2 % codes on L2 channel
- GPS_Week % GPS week (to go with Toe), (NOT Mod 1024)
- L2Pdata % L2 P data flag
- accuracy % SV user range accuracy (meters)
- health % Satellite health
- TGD % Group delay (seconds)
- IODC % Issue of Data, Clock
- ttx % Transmission time of message (seconds)
- Fit_interval %fit interval (hours), zero if not known
Please let me know if there is a way to parse the Navigation message which I am receiving to these parameters.
Also let me know if I am going in the wrong direction.
Any lead will be appreciated.