Resistor grounded at both ends
"SYSGND" is only ground by name (with respect to the power supply ground). Truth of the matter is that it isn't directly connected to the ACTUAL ground (of the power supply - the battery in this case). Instead it connects to the ACTUAL ground through the resistor which has a resistance of 0.010 ohms. This means that when current is flowing from the negative side of the battery into the circuit (electron flow, not conventional current flow) there is a very small voltage drop across the resistor proportional to the current being drawn by the circuit. This IC measures this tiny voltage drop and uses it to calculate the current. For all practical purposes, however, this voltage drop is so low that "SYSGND" is close enough to the actual GND that it is considered "GND".