Download Inertial Explorer User Guide

Chapter 3
3.3.3
Data and File Formats
BIF/BIR/BTF/BTR Files
Here is the C/C++ structure definition of the header, which is 512 bytes:
typedef struct
{
char Str[16];
long HdrSize;
long IsExtended;
long RecSize;
long Reserved1;
double Interval;
char ProgramName[32];
char VersionName[32];
char Direction[16];
char Reserved2[392];
} imu_hdr_type;
// $IMUOUT
// size of this header
// true if extended format used
// size of this record (see note below)
// for later, zero
// data interval (s)
// program name that created this file
// version that produced file
// "Forward", "Reverse" or "Combined"
// reserved for future use (zero at creation of new file)
 The RecSize variable should always be checked as the structure size and format may change in future versions.
Contact Waypoint Support if you have any questions.
The single header is then followed by the 121-byte structure type below for each processed epoch:
typedef struct
{
double GpsTime;
// GPS time of this record (seconds of week)
short WeekNum;
// week number
unsigned char FixedFlagAndHeave[2];
// bit 0: Fixed solution=on/float solution=off
// bits 1-14: heave (+/-16.384 m)
// bit 15: sign of heave
plh_type_double GeoPos;
// geographic position of this record (deg, deg, m)
fxyz_type LLVel;
// local level velocity (m/s)
fxyz_type LLAcc;
// local level acceleration (m/s2)
iatt_type LLAtt;
// local level attitude (deg) (scaled)
fxyz_type LLAttDot;
// body frame rotational rate (deg/s)
fxyz_type stdPos;
// position standard deviations (m)
fxyz_type stdVel;
// velocity standard deviations (m/s)
fxyz_type stdAtt;
// attitude standard deviations (deg)
char Reserved[1];
} imu_outrec_type;
typedef struct
{
double phi, lamda;
double ht;
} plh_type_double;
// latitude and longitude (deg)
// ellipsoidal height (m)
typedef struct
{
float x, y, z;
} fxyz_type;
typedef struct
{
signed long iRoll, iPitch, iYaw;
} iatt_type;
// attitude (deg); scaled by 1.0e-6
The rotation matrix from body-to-local level is defined as: RBLL = R3(yaw) * R1(pitch) * R2(roll)
44
Inertial Explorer 8.50 User Guide Rev 9