Vehicle speed acquisition device and abnormal noise diagnostic system

A vehicle speed acquisition device that acquires a vehicle speed of a vehicle based on position information of the vehicle, the vehicle speed acquisition device comprising:

• a position information acquisition unit for acquiring the position information at a first time interval that is determined in advance;
• a sound pressure acquisition unit for acquiring a sound pressure of sound emitted from the vehicle at a second time interval that is shorter than the first time interval;
• a vehicle speed estimation unit for estimating the vehicle speed at an acquisition timing of the position information and the vehicle speed at an acquisition timing of the sound pressure, based on the position information acquired by the position information acquisition unit and the first and the second time intervals;
• a vehicle speed change rate acquisition unit for acquiring a change rate of the vehicle speed between acquisition timings of the position information, based on the vehicle speed at the acquisition timing of the position information estimated by the vehicle speed estimation unit, and the first time interval;
• a sound pressure change rate acquisition unit for acquiring a change rate of the sound pressure between acquisition timings of the sound pressure, based on the sound pressure acquired by the sound pressure acquisition unit, and the second time interval;
• and
• an estimation accuracy acquisition unit for acquiring an estimation accuracy of the vehicle speed by the vehicle speed estimation unit, based on the change rate of the vehicle speed and the change rate of the sound pressure, and associating the estimation accuracy that is acquired, with the vehicle speed at the acquisition timing of the sound pressure estimated by the vehicle speed estimation unit.