C# code snippet to read an Applanix SBET file

The smoothed best estimated trajectory (SBET) file of an air survey flight created and exported by the Applanix PosPac software is a simple binary format. The SBET file is just a series of records with the following double fields, as described by the C# code below:

public class SbetRecord

{

    public double time;    //GPS seconds of week

    public double latRad;    //latitude in radians

    public double lonRad;    //longitude in radians

    public double alt;    //altitude

    public double xVel;    //velocity in x direction

    public double yVel;    //velocity in y direction

    public double zVel;    //velocity in z direction

    public double roll;    //roll angle

    public double pitch;    //pitch angle

    public double heading;    //heading angle

    public double wander;    //wander

    public double xForce;    //force in x direction

    public double yForce;    //force in y direction

    public double zForce;    //force in z direction

    public double xAngRate;    //angular rate in x direction

    public double yAngRate;    //angular rate in y direction

    public double zAngRate;    //angular rate in z direction

}

Then just use a BinaryReader to open up the file and read in the fields as doubles as shown in the code snippet below.

SbetRecord rec = new SbetRecord();

// Open an SBET file for reading...

BinaryReader reader = new BinaryReader(File.Open(@"C:\Temp\sbet1.out", FileMode.Open, FileAccess.Read));

// ...read a record...

rec.time = reader.ReadDouble();

rec.latRad = reader.ReadDouble();

rec.lonRad = reader.ReadDouble();

rec.alt = reader.ReadDouble();

rec.xVel = reader.ReadDouble();

rec.yVel = reader.ReadDouble();

rec.zVel = reader.ReadDouble();

rec.roll = reader.ReadDouble();

rec.pitch = reader.ReadDouble();

rec.heading = reader.ReadDouble();

rec.wander = reader.ReadDouble();

rec.xForce = reader.ReadDouble();

rec.yForce = reader.ReadDouble();

rec.zForce = reader.ReadDouble();

rec.xAngRate = reader.ReadDouble();

rec.yAngRate = reader.ReadDouble();

rec.zAngRate = reader.ReadDouble();

// ... etc ...