Inertial measurement unit

An inertial measurement unit comprising:

• a sensor unit having an inertial sensor therein;
• a first substrate disposed below the sensor unit, a top surface of the first substrate facing a bottom surface of the sensor unit, the first substrate having a first plurality of openings therein, first, second, third, and fourth openings of the first plurality of openings being located at four corners of a virtual rectangle on the first substrate;
• a first plurality of spacers located at an outermost periphery of the top surface of the first substrate and coupling the sensor unit and the first substrate together;
• a second substrate disposed below the first substrate, a top surface of the second substrate facing a bottom surface of the first substrate;
• four attaching magnets disposed on a bottom surface of the second substrate and attaching the inertial measurement unit to a measurement target;
• a first elastic member provided on both the top and bottom surfaces of the first substrate via the first opening;
• a second elastic member provided on both the top and bottom surfaces of the first substrate via the second opening;
• a third elastic member provided on both the top and bottom surfaces of the first substrate via the third opening;
• a fourth elastic member provided on both the top and bottom surfaces of the first substrate via the fourth opening;
• a first fixing member penetrating, pressing and fixing the first substrate and the first elastic member to the second substrate via the first opening;
• a second fixing member penetrating, pressing and fixing the first substrate and the second elastic member to the second substrate via the second opening;
• a third fixing member penetrating, pressing and fixing the first substrate and the third elastic member to the second substrate via the third opening;
• and
• a fourth fixing member penetrating, pressing and fixing the first substrate and the fourth elastic member to the second substrate via the fourth opening,
• wherein each of the first, second, third, and fourth elastic members has a first part arranged between the sensor unit and the first substrate, a second part located between the first substrate and the second substrate, and a third part coupled to the second part and located inside one of the first, second, third, and fourth openings,
• a distance between the bottom surface of the sensor unit and the top surface of the first substrate is larger than a distance between the bottom surface of the first substrate and the top surface of the second substrate,
• first and second magnets of the four attaching magnets are respectively located adjacent to the first and second openings in a plan view,
• third and fourth magnets of the four attaching magnets are respectively located adjacent to the third and fourth openings in the plan view, and
• the first, second, third, and fourth elastic members completely overlap the sensor unit in the plan view.