TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2425 SUBJECT: IPN triangulation of GRB031020 (large error box) DATE: 03/10/23 16:56:06 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses, Konus, and Mars Odyssey GRB teams, I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and A. Sanin, on behalf of the HEND-Odyssey GRB team, W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of the GRS/Odyssey GRB team, and E. Mazets and S. Golenetskii, on behalf of the Konus-Wind GRB team, report: Ulysses, Mars Odyssey-HEND, and Konus-Wind observed this GRB at 07811 seconds. As observed by Ulysses, it had a duration of approximately 45 seconds, a 25-100 keV fluence of approximately 4.4E-06 erg/cm2, and a peak flux of approximately 4.6E-07 erg/cm2 s over 0.50 seconds. We have triangulated it to a preliminary, 3 sigma error box whose approximate area is 5000 sq. arcmin. and whose coordinates are: RA(2000) DEC(2000) ERROR BOX CENTER: 11 h 58 m 30.84 s -69 o 26 ' 9.93 " ERROR BOX CORNER 1: 11 h 45 m 46.63 s -69 o 40 ' 56.36 " ERROR BOX CORNER 2: 10 h 32 m 13.96 s -69 o 27 ' 47.92 " ERROR BOX CORNER 3: 13 h 13 m 6.26 s -66 o 58 ' 57.37 " ERROR BOX CORNER 4: 12 h 10 m 52.13 s -69 o 7 ' 59.60 " This error box may be improved, but as Ulysses, Earth, and Mars are still almost aligned, a small error box cannot be derived for this event.