

Obviously not.  Count rates are too low and signal rise times too long
for this to be possible.  The CGRO, is, what, 10 meters long?  You'd
need to time to an accuracy of nanoseconds to do this.

What BATSE actually does is measure the relative strength in each of
the detectors (also as a function of photon energy).  Each of the
detectors does not have isotropic response.  To do this right one must
model the scattering of photons in the material around each detector,
and even scattering of photons off the Earth's atmosphere back onto
the spacecraft.  I believe they have now reduced the error to about 2
degrees.