1 files changed, 62 insertions, 0 deletions
diff --git a/src/include/sgp4.h b/src/include/sgp4.h
new file mode 100644
index 0000000..289b969
--- /dev/null
+++ b/src/include/sgp4.h
@@ -0,0 +1,62 @@
+/* H+
+ *      Title     : sgp4.h
+ *      Author    : Bryce A. Roberts
+ *      Date      : 23 February 1999
+ *      Synopsis  : header file for SGP4 propagation routines
+ *      SCCS      : @(#)sgp4.h	1.1 03/04/03
+ *      Revisions :
+ *      mm/dd/yy name   description
+ * H-
+ */
+
+#ifndef _SGP4_H
+#define _SGP4_H
+
+#include <math.h>
+#include <stdlib.h>
+#include <time.h>
+#include <strings.h>
+
+#define MJD2000      (51544.0)
+
+/* the data structure itself */
+struct sgp4_st {
+  /* NORAD tle components */
+  double epochTime, n0, n0dt, n0dt2, bstar, i0, raan, e0, w0, M0;
+
+  /* derived variables */
+  double n0dp, a0dp, q0ms4, theta, theta_2, zeta_4, beta0_2, eta, C1, 
+    C1_2, C1_3, C1_4, C3, C4, C5, D2, D3, D4, mdot, wdot, raandot; 
+  };
+
+typedef struct sgp4_st * SGP4;
+
+/* create a new instance of SGP4 */
+extern SGP4 SGP4_create(void);
+
+/* destroy an instance of SGP4 */
+extern void SGP4_destroy(SGP4 sgp4);
+
+/* convert NORAD time string to TJD */
+extern int SGP4_getTime(const char *str, double *t);
+
+/* do time-invariant initializations */
+extern void SGP4_init(SGP4 sgp4);
+
+/* get a state vector at a point in time */
+extern void SGP4_getStateVector(SGP4 sgp4, double t, double pos[3], 
+			       double vel[3]);
+
+/* finds the pole (orbit plane normal) */
+extern void SGP4_getPole(double pos[3], double vel[3], double pole[3]);
+
+/* sets the elements of an instance of SGP4 */
+extern void SGP4_set(SGP4 sgp4, double epochTime, double n0dt, double n0dt2,
+		     double bstar, double i0, double raan, double e0,
+		     double w0, double M0, double n0);
+
+/* precesses a direction vector from t1 to t2 */
+void SGP4_precess(double v[3], double t1, double t2);
+
+
+#endif