Structure in C for the Fitted ACF data

Summary

A description of the data structure in the C language used to store the Fitted ACF Data.

Description

The FitACF algorithm is used to derive doppler velocities, spectral widths and powers from the raw ACF data. Listed below is the C data structure struct FitData used to store the fitted ACF data.

Array Limits

The array limits are defined as macros in the header superdarn/limit.h.

#define MAX_RANGE 300   

struct FitData

The fitted ACF data structure is defined in the header superdarn/fitdata.h.

struct FitData {
  struct {
    int major;                     /* major revision */
    int minor;                     /* minor revision */
  } revision;             
  struct FitNoise noise;           /* noise parameters */
  struct FitRange rng[MAX_RANGE];  /* ACF range data */
  struct FitRange xrng[MAX_RANGE]; /* XCF range data */
  struct FitElv  elv[MAX_RANGE];   /* elevation angle data */
};

struct FitNoise

struct FitNoise { 
  double vel;                      /* velocity from fitting the noise ACF */
  double skynoise;                 /* sky noise */
  double lag0;                     /* lag-zero power of noise ACF */
};

struct FitRange

struct FitRange { 
  double v;                        /* velocity from ACF */
  double v_err;                    /* velocity error from ACF */
  double p_0;                      /* lag zero power */
  double p_l;                      /* power from lambda fit of ACF */
  double p_l_err;                  /* power error from lambda fit of ACF */
  double p_s;                      /* power from sigma fit of ACF */
  double p_s_err;                  /* power error from sigma fit of ACF */
  double w_l;                      /* spectral width from lambda fit of ACF */
  double w_l_err;                  /* spectral width error from lambda fit of ACF */
  double w_s;                      /* spectral width from sigma fit of ACF */
  double w_s_err;                  /* spectral width error from sigma fit of ACF*/ 
  double phi0;                     /* phase determination at lag zero of the ACF */
  double phi0_err;                 /* phase determination error at lag zero of the ACF */
  double sdev_l;                   /* standard deviation of lambda fit */
  double sdev_s;                   /* standard deviation of sigma fit */
  double sdev_phi;                 /* standard deviation of phase fit */
  int qflg;                        /* quality flag */
  int gsct;                        /* ground scatter flag */
  char nump;                       /* number of points in the fit */
};

struct FitElv

struct FitElv { 
  double normal;                   /* angle of arrival estimate */
  double low;                      /* lowest estimate of angle of arrival */
  double high;                     /* highest estimate of angle of arrival */
};

References

• This information is sourced from the RFC: 0014 previously in the RST RFC documentation that was written by R.J. Barnes.

History

• 2007/03/26 Revision to reflect changes in array size.
• 2004/11/19 Initial Revision.