Alpha5 tle support

rffit.c

@@ -112,6 +112,7 @@ void format_tle(orbit_t orb,char *line1,char *line2)
   int i,csum;
   char sbstar[]=" 00000-0",bstar[13];
   char csumstr[2];
+  char satstr[6];
 
   // Format Bstar term
   if (fabs(orb.bstar)>1e-9) {
@@ -120,8 +121,10 @@ void format_tle(orbit_t orb,char *line1,char *line2)
     sbstar[4] = bstar[5];  sbstar[5] = bstar[6];  sbstar[6] = bstar[8];  sbstar[7] = bstar[10];  sbstar[8] = '\0';
   }
   // Print lines
-  sprintf(line1,"1 %05dU          %2d%012.8f  .00000000  00000-0 %8s 0    0",orb.satno,orb.ep_year-2000,orb.ep_day,sbstar);
-  sprintf(line2,"2 %05d %8.4f %8.4f %07.0f %8.4f %8.4f %11.8f    0",orb.satno,DEG(orb.eqinc),DEG(orb.ascn),1E7*orb.ecc,DEG(orb.argp),DEG(orb.mnan),orb.rev);
+  number_to_alpha5(orb.satno,satstr);
+  satstr[5]='\0';
+  sprintf(line1,"1 %5sU          %2d%012.8f  .00000000  00000-0 %8s 0    0",satstr,orb.ep_year-2000,orb.ep_day,sbstar);
+  sprintf(line2,"2 %5s %8.4f %8.4f %07.0f %8.4f %8.4f %11.8f    0",satstr,DEG(orb.eqinc),DEG(orb.ascn),1E7*orb.ecc,DEG(orb.argp),DEG(orb.mnan),orb.rev);
 
   // Compute checksums
   for (i=0,csum=0;i<strlen(line1);i++) {

satutl.c

@@ -4,13 +4,85 @@
 
 
 #include "sgdp4h.h"
-
 #include <ctype.h>
 
 static char *st_start(char *buf);
 static long i_read(char *str, int start, int stop);
 static double d_read(char *str, int start, int stop);
 
+// Fixed mapping
+// Only capital letters and numbers are used in Alpha-5. The letters “I” and “O” are omitted to avoid confusion with the numbers “1” and “0”. 
+const char mapping[] = "0123456789ABCDEFGHJKLMNPQRSTUVWXYZ";
+
+// Function to convert alpha5 format to number
+int alpha5_to_number(const char *s)
+{
+    // Split components
+    char first_char = s[0];
+    int digits = 0;
+    sscanf(s + 1, "%4d", &digits);  // Get the last four digits
+
+    // Decode first character
+    int first_digit = 0;
+    if (first_char == ' ') {
+        first_digit = 0;
+    } else if (isdigit(first_char)) {
+        first_digit = first_char - '0';
+    } else {
+        for (int i = 0; mapping[i] != '\0'; i++) {
+            if (mapping[i] == first_char) {
+                first_digit = i;
+                break;
+            }
+        }
+    }
+
+    // Create and return number
+    return first_digit * 10000 + digits;
+}
+
+// Function to convert number to alpha5 format
+void number_to_alpha5(int number, char *result)
+{
+    // Split components
+    int first_digit = number / 10000;
+    int digits = number % 10000;
+
+    // Get char
+    char first_char = mapping[first_digit];
+
+    // Create string
+    sprintf(result, "%c%04d", first_char, digits);
+
+    return;
+}
+
+// Function to strip leading spaces
+void strip_leading_spaces(const char *s, char *result)
+{
+    while (*s == ' ') {
+        s++;  // Skip leading spaces
+    }
+    strcpy(result, s);  // Copy the remainder of the string
+
+    return;
+}
+
+// Function to zero pad a string
+void zero_pad(const char *s, char *result)
+{
+    char stripped[6];  // Temporarily store the string without leading spaces
+    strip_leading_spaces(s, stripped);
+
+    if (isdigit(stripped[0])) {
+        int value = atoi(stripped);
+        sprintf(result, "%05d", value);
+    } else {
+        strcpy(result, stripped);  // No zero-padding for non-digit strings
+    }
+}
+
+
  /* ====================================================================
    Read a string from key board, remove CR/LF etc.
    ==================================================================== */
@@ -78,13 +150,17 @@ int read_twoline(FILE *fp, long search_satno, orbit_t *orb, char *satname)
   static char search[ST_SIZE];
   static char line1[ST_SIZE];
   static char line2[ST_SIZE];
+  char search_satstr[6];
   char *st1, *st2;
   int found = 0;
   double bm, bx;
 
   st1 = line1;
   st2 = line2;
 
+  // alpha5 designation to search
+  number_to_alpha5(search_satno, search_satstr);
+
   do {
     if(fgets(line1, ST_SIZE-1, fp) == NULL) return -1;
     st1 = st_start(line1);
@@ -93,11 +169,14 @@ int read_twoline(FILE *fp, long search_satno, orbit_t *orb, char *satname)
   } while((st1[0] != '1') || (st1[1] != ' '));
 
   if (search_satno != 0) {
-    sprintf(search, "1 %05ld", search_satno);
+    sprintf(search, "1 %5s", search_satstr);
   } else {
     // If no search_satno given, set it to the currently read one
     // so next do/while loop will find it
-    search_satno = atol(st1+2);
+    //search_satno = atol(st1+2);
+    strncpy(search_satstr, st1+2, 5);
+    search_satstr[5]='\0';
+    search_satno=alpha5_to_number(search_satstr);
     strncpy(search, line1, 7);
     search[7] = '\0';
   }

satutl.h

@@ -17,13 +17,17 @@ void conditional_copy_satname(char * satname, char * current_line);
 int  read_twoline(FILE *fp, long satno, orbit_t *orb, char *satname);
 void *vector(size_t num, size_t size);
 void print_orb(orbit_t *orb);
-
+int alpha5_to_number(const char *s);
+void number_to_alpha5(int number, char *result);
+void zero_pad(const char *s, char *result);
+void strip_leading_spaces(const char *s, char *result);
+
 /** aries.c **/
 double gha_aries(double jd);
 
 /** ferror.c **/
 void fatal_error(const char *format, ...);
-
+  
 #ifdef __cplusplus
 }
 #endif

tests/data/alpha5.tle

@@ -0,0 +1,6 @@
+0 ISS (ZARYA)
+1 B5544U 98067A   24356.58519896  .00014389  00000-0  25222-3 0  9992
+2 B5544  51.6403 106.8969 0007877   6.1421 113.2479 15.50801739487615
+0 ISS (ZARYA)
+1 Z9999U 98067A   24356.58519896  .00014389  00000-0  25222-3 0  9992
+2 Z9999  51.6403 106.8969 0007877   6.1421 113.2479 15.50801739487615

tests/tests_rftles.c

@@ -45,6 +45,18 @@ int setup(void **state) {
   return 0;
 }
 
+int setup_alpha5(void **state) {
+  tle_array_t * tle_array = load_tles("tests/data/alpha5.tle");
+
+  if (tle_array == NULL) {
+    return -1;
+  }
+
+  *state = tle_array;
+
+  return 0;
+}
+
 int teardown(void **state) {
   free_tles(*state);
 
@@ -212,6 +224,32 @@ void TLE_load_catalog_id_from_file(void **state) {
   assert_string_equal(tle->name, "OSCAR 7 (AO-7)");
 }
 
+void TLE_decode_alpha5_designation(void **state) {
+  tle_array_t tle_array = **(tle_array_t **)state;
+
+  assert_non_null(tle_array.tles);
+  assert_int_equal(tle_array.number_of_elements, 2);
+
+  // 1st element, B5544 - ISS
+  tle_t * tle = get_tle_by_catalog_id(&tle_array, 115544);
+
+  assert_non_null(tle->name);
+  assert_string_equal(tle->name, "ISS (ZARYA)");
+
+  assert_string_equal(tle->orbit.desig, "98067A");
+  assert_int_equal(tle->orbit.satno, 115544);
+
+  // 2nd element, 339999 - ISS
+  tle = get_tle_by_catalog_id(&tle_array, 339999);
+
+  assert_non_null(tle->name);
+  assert_string_equal(tle->name, "ISS (ZARYA)");
+
+  assert_string_equal(tle->orbit.desig, "98067A");
+  assert_int_equal(tle->orbit.satno, 339999);
+
+}
+
 // Entry point to run all tests
 int run_tle_tests() {
   const struct CMUnitTest tests[] = {
@@ -221,6 +259,7 @@ int run_tle_tests() {
     cmocka_unit_test_setup_teardown(TLE_load_index_from_file, setup, teardown),
     cmocka_unit_test_setup_teardown(TLE_load_invalid_catalog_id_from_file, setup, teardown),
     cmocka_unit_test_setup_teardown(TLE_load_catalog_id_from_file, setup, teardown),
+    cmocka_unit_test_setup_teardown(TLE_decode_alpha5_designation, setup_alpha5, teardown),    
   };
 
   return cmocka_run_group_tests_name("TLE", tests, NULL, NULL);