Location of acceleration and gyro chip within Wireless Force Acceleration Sensor (PS-3202)

Where is the point at which the acceleration on the PS-3202 is measured?

The acceleration and gyroscope chip are located on the centerline of the sensor under the axis system printed on the top of the sensor. This is marked with the red dot in the diagram below.  The sensor chip is mounted on the same conductor plane as the board that the battery contacts are connected to.  The arch in the case on the back side of the sensor is there to accommodate the chip (as it stands a little bit off the surface of the board).