search

csete / gpredict

Gpredict satellite tracking application
http://gpredict.oz9aec.net/
GNU General Public License v2.0
861 stars 252 forks source link

Gpredict hangs when attempting to use a TLE with a zero eccentricity. #156

Closed darksidelemm closed 5 years ago

darksidelemm commented 5 years ago

The following TLE (created during pre-launch of the SSO-A mission) causes gpredict to hang badly:

SSO-A
1 70003U 18835A   18336.80285382  .00000000  00000-0  00000-0 0    05
2 70003  97.8442  45.4226 0000000 100.4497 180.6751 14.96286186    03

In fact, I have to kill -9 to be able to exit out of gpredict. This bug is reproducible, just try and use the above TLE. Probably something to do with the zero eccentricity term.

csete commented 5 years ago

Confirmed and definitely a bug. It is indeed the 0 eccentricity that makes it malfunction.

A temporary workaround suggested for those who can build from source:

diff --git a/src/sgpsdp/sgp_in.c b/src/sgpsdp/sgp_in.c
index 5a23d54..c7e3e16 100644
--- a/src/sgpsdp/sgp_in.c
+++ b/src/sgpsdp/sgp_in.c
@@ -214,6 +214,8 @@ Convert_Satellite_Data (char *tle_set, tle_t *tle)
        strncpy (&buff[1], &tle_set[95], 7);
        buff[8] = '\0';
        tle->eo = g_ascii_strtod (buff, NULL);
+    if (tle->eo == 0.0)
+        tle->eo = 0.0001;

        /* Satellite's Argument of Perigee (degrees) */
        strncpy (buff, &tle_set[103], 8);
kerel-fs commented 3 years ago

I just re-discovered this bug while trying to load a pre-launch TLE for Qubik. While fixed in master, there was no release of gpredict done since this was fixed in Dec 2018.