#ifndef _PREDICT_DEFS_H_ #define _PREDICT_DEFS_H_ #include /** \name Geosynchronous orbit definitions * Requirements for an orbit to be called geosynchronous. */ ///@{ ///lower mean motion for geosynchronous satellites #define GEOSYNCHRONOUS_LOWER_MEAN_MOTION 0.9 ///upper mean motion for geosynchronous satellites #define GEOSYNCHRONOUS_UPPER_MEAN_MOTION 1.1 ///upper eccentricity for geosynchronous satellites #define GEOSYNCHRONOUS_ECCENTRICITY_THRESHOLD 0.2 ///upper inclination for geosynchronous satellites #define GEOSYNCHRONOUS_INCLINATION_THRESHOLD_DEGREES 70 ///@} /** \name Mathematical constants * Mathematical convenience constants used by sgp4/sdp4 and related routines. */ ///@{ /// pi #define PI 3.14159265358979323846 /// pi/2 #define PI_HALF 1.57079632679489656 /// 2*pi #define TWO_PI 6.28318530717958623 /// 3*pi/2 #define THREE_PI_HALF 4.71238898038468967 /// 2/3 #define TWO_THIRD 6.6666666666666666E-1 ///@} /** \name Time constants * Constants used for time conversions. */ ///@{ ///Number of minutes per day, XMNPDA in spacetrack report #3 #define MINUTES_PER_DAY 1.44E3 ///Number of seconds per day #define SECONDS_PER_DAY 8.6400E4 ///Difference between libpredict's predict_julian_date_t and the julian time format used in some of the internal functions #define JULIAN_TIME_DIFF 2444238.5 ///@} /** \name Physical properties * General physical properties and definitions. */ ///@{ ///J3 Harmonic (WGS '72), XJ3 in spacetrack report #3 #define J3_HARMONIC_WGS72 -2.53881E-6 ///WGS 84 Earth radius km, XKMPER in spacetrack report #3 #define EARTH_RADIUS_KM_WGS84 6.378137E3 ///Flattening factor #define FLATTENING_FACTOR 3.35281066474748E-3 ///Earth rotations per siderial day #define EARTH_ROTATIONS_PER_SIDERIAL_DAY 1.00273790934 ///Solar radius in kilometers (IAU 76) #define SOLAR_RADIUS_KM 6.96000E5 ///Astronomical unit in kilometers (IAU 76) #define ASTRONOMICAL_UNIT_KM 1.49597870691E8 ///Upper elevation threshold for nautical twilight #define NAUTICAL_TWILIGHT_SUN_ELEVATION -12.0 ///Speed of light in vacuum #define SPEED_OF_LIGHT 299792458.0 ///Angular velocity of Earth in radians per seconds #define EARTH_ANGULAR_VELOCITY 7.292115E-5 ///@} /** \name Iteration constants * Constants used in iteration functions like predict_max_elevation(), * predict_next_aos() and predict_next_los(). */ ///@{ ///Threshold used for fine-tuning of AOS/LOS #define AOSLOS_HORIZON_THRESHOLD 0.3 ///Threshold used for comparing lower and upper brackets in find_max_elevation #define MAXELE_TIME_EQUALITY_THRESHOLD FLT_EPSILON ///Maximum number of iterations in find_max_elevation #define MAXELE_MAX_NUM_ITERATIONS 10000 ///@} /** \name General spacetrack report #3 constants * These constants are also used outside of SGP4/SDP4 code. The * constants/symbols are defined on page 76 to page 78 in the report. */ ///@{ ///k_e = sqrt(Newton's universal gravitational * mass of the Earth), in units (earth radii per minutes)^3/2 #define XKE 7.43669161E-2 ///Corresponds to 1/2 * J_2 * a_E^2. J_2 is the second gravitational zonal harmonic of Earth, a_E is the equatorial radius of Earth. #define CK2 5.413079E-4 ///@} /** \name Specific spacetrack report #3 constants * These constants are only used by SGP4/SDP4 code. The constants/symbols are * defined on page 76 to page 78 in the report. */ ///@{ ///Shorthand for 10^-6. #define E6A 1.0E-6 ///Distance units / Earth radii. #define AE 1.0 ///Corresponds to -3/8 * J_4 * a_E^4, where J_4 is the fourth gravitational zonal harmonic of Earth. #define CK4 6.209887E-7 ///Parameter for SGP4/SGP8 density function. #define S_DENSITY_PARAM 1.012229 ///Corresponds to (q_0 - s)^4 in units (earth radii)^4, where q_0 and s are parameters for the SGP4/SGP8 density function. #define QOMS2T 1.880279E-09 ///@} /** \name Constants in deep space subroutines * Not defined in spacetrack report #3. * * The constants might originally be defined in Hujsak (1979) and/or Hujsak * and Hoots (1977), but this is unavailable on the Internet. Reiterated in F. * R. Hoots, P. W. Schumacher and R. A. Glober, "A HISTORY OF ANALYTICAL * ORBIT MODELING IN THE UNITED STATES SPACE SURVEILLANCE SYSTEM", 2004. Page * numbers below refer to this article. */ ///@{ ///Solar mean motion (n_s in units radians/minute, p. 29) #define ZNS 1.19459E-5 ///Solar perturbation coefficient (C_s in units radians/minute, p. 29) #define C1SS 2.9864797E-6 ///Solar eccentricity (e_s, p. 29) #define ZES 1.675E-2 ///Lunar mean motion (n_m in units radians/minute, p. 29) #define ZNL 1.5835218E-4 ///Lunar perturbation coefficient (C_m in units radians/minute, p. 29) #define C1L 4.7968065E-7 ///Lunar eccentricity (e_m, p. 29) #define ZEL 5.490E-2 ///Cosine of the solar inclination (not defined directly in the paper, but corresponds with cos(I_s) with I_s as the solar inclination on p. 29) #define ZCOSIS 9.1744867E-1 ///Sine of the solar inclination (sin(I_s), I_s on p. 29. See comment above) #define ZSINIS 3.9785416E-1 ///Corresponds to sin(\omega_s) (\omega_s defined on p. 29, no description. See comment above) #define ZSINGS -9.8088458E-1 ///Corresponds to cos(\omega_s) (\omega_s defined on p. 29, no description. See comment above) #define ZCOSGS 1.945905E-1 ///Constants for one-day resonance conditions, satellite-independent for 1-day period satellites (Initialization of resonance effects of Earth gravity, Q_22, Q_31 and Q_33, p. 31) #define Q22 1.7891679E-6 ///See above #define Q31 2.1460748E-6 ///See above #define Q33 2.2123015E-7 ///Constants for secular update for resonance effects of Earth gravity (G_22, G_32, G_44, G_52 and G_54, p. 36) #define G22 5.7686396 ///See above #define G32 9.5240898E-1 ///See above #define G44 1.8014998 ///See above #define G52 1.0508330 ///See above #define G54 4.4108898 ///Constants for 1/2-day resonance conditions, satellite-independent for 1/2-day period satellites (Initialization for resonance effects of Earth gravity, sqrt(C_ij^2 + S_ij^2) where ij = 22, 32, 44, 52 and 54, p. 32) #define ROOT22 1.7891679E-6 ///See above #define ROOT32 3.7393792E-7 ///See above #define ROOT44 7.3636953E-9 ///See above #define ROOT52 1.1428639E-7 ///See above #define ROOT54 2.1765803E-9 ///The time-derivative of the Greenwich hour angle in radians per minute (\dot{\theta}, used on p. 36. Not directly defined in report, but values and naming are consistent with this) #define THDT 4.3752691E-3 ///@} #endif