Method and system for determining core orientation

A method of determining core orientation of a core sample cut from the ground by a drill rig having a drill string and a drill bit, the method comprising:

• providing, within the drill string and proximate the drill bit, a downhole data acquisition tool (DAT) comprising:
• (a) a sensor assembly including at least one of a gyroscope, accelerometer, or magnetometer;
• (b) a downhole processor;
• and
• (c) a memory;
• continuously sampling sensory assembly data during drilling, sensor assembly data indicative of rotational and angular position of the DAT;
• acquiring, by one or more downhole sensors of the DAT and by one or more at-surface sensors, rig operational data, rig operational data constituting both near-bit rig data and at-surface rig data;
• storing the sensor assembly data and rig operational data;
• processing the sensor assembly data;
• computing a core orientation value;
• detecting a core break event via a specific pattern in the rig operational data;
• and
• updating, in response the core break event, the core orientation value.