Examples of systems and methods for locating movable objects such as carts (e.g., shopping carts) are disclosed. Such systems and methods can use dead reckoning techniques to estimate the current position of the movable object. Various techniques for improving accuracy of position estimates are disclosed, including compensation for various error sources involving the use of magnetometer and accelerometer, and using vibration analysis to derive wheel rotation rates. Also disclosed are various techniques to utilize characteristics of the operating environment in conjunction with or in lieu of dead reckoning techniques, including characteristic of environment such as ground texture, availability of signals from radio frequency (RF) transmitters including precision fix sources. Such systems and methods can be applied in both indoor and outdoor settings and in retail or warehouse settings.

An approach to determining vehicle usage makes use of a sensor that provides a vibration signal associated with the vehicle, and that vibration signal is used to infer usage. Usage can include distance traveled, optionally associated with particular ranges of speed or road type. In a calibration phase, auxiliary measurements, for instance based on GPS signals, are used to determine a relationship between the vibration signal and usage. In a monitoring phase, the determined relationship is used to infer usage from the vibration signal.

An approach to determining vehicle usage makes use of a sensor that provides a vibration signal associated with the vehicle, and that vibration signal is used to infer usage. Usage can include distance traveled, optionally associated with particular ranges of speed or road type. In a calibration phase, auxiliary measurements, for instance based on GPS signals, are used to determine a relationship between the vibration signal and usage. In a monitoring phase, the determined relationship is used to infer usage from the vibration signal.

An inertial measurement unit includes: a substrate including a first surface and a second surface orthogonal to a Z-axis and having a front-back relationship with each other; an inertial sensor installed at the first surface of the substrate; a semiconductor device installed at the second surface of the substrate and electrically coupled to the inertial sensor; and a plurality of lead terminals coupled to the substrate and configured to support the substrate to a mounting target surface. The plurality of lead terminals have a first part coupled to the substrate, a second part mounted at the mounting target surface, and a third part located between the first part and the second part and extending in a direction having a component along the Z-axis. The semiconductor device is exposed from between the plurality of lead terminals, as viewed in a plan view from a direction orthogonal to the Z-axis.

An inertial measurement unit includes: a substrate including a first surface and a second surface orthogonal to a Z-axis and having a front-back relationship with each other; an inertial sensor installed at the first surface of the substrate; a semiconductor device installed at the second surface of the substrate and electrically coupled to the inertial sensor; and a plurality of lead terminals coupled to the substrate and configured to support the substrate to a mounting target surface. The plurality of lead terminals have a first part coupled to the substrate, a second part mounted at the mounting target surface, and a third part located between the first part and the second part and extending in a direction having a component along the Z-axis. The semiconductor device is exposed from between the plurality of lead terminals, as viewed in a plan view from a direction orthogonal to the Z-axis.

A method for determining a rotational frequency of a positive displacement motor positioned in a downhole portion of a drill string, the method including: providing at least one measurement device for measuring a property of a part of the drill string; providing a processor for processing a signal output by the at least one measurement device; operating the positive displacement motor whilst the part of the drill string is in a non-driven state; receiving the signal at the processor; determining, using the processor, a frequency spectrum of the signal; and determining the rotational frequency of the positive displacement motor by: identifying a peak in the frequency spectrum in a pre-determined frequency range associated with an expected rotational frequency of the positive displacement motor; and/or identifying a peak in the frequency spectrum having a pre-determined peak width associated with an expected rotational frequency of the positive displacement motor.

A method for determining a rotational frequency of a positive displacement motor positioned in a downhole portion of a drill string, the method including: providing at least one measurement device for measuring a property of a part of the drill string; providing a processor for processing a signal output by the at least one measurement device; operating the positive displacement motor whilst the part of the drill string is in a non-driven state; receiving the signal at the processor; determining, using the processor, a frequency spectrum of the signal; and determining the rotational frequency of the positive displacement motor by: identifying a peak in the frequency spectrum in a pre-determined frequency range associated with an expected rotational frequency of the positive displacement motor; and/or identifying a peak in the frequency spectrum having a pre-determined peak width associated with an expected rotational frequency of the positive displacement motor.

A speed monitoring device and a passenger conveying device. The speed monitoring device includes a transmission rotor disposed on a shaft side surface of a shaft of which the speed is to be measured and rotating with rotation of the shaft of which the speed is to be measured; an encoder having an input shaft, the input shaft of the encoder being connected to the transmission rotor and rotating with rotation of the transmission rotor; and a mounting bracket for securing the transmission rotor and the encoder to a position where they are to be mounted.

A speed monitoring device and a passenger conveying device. The speed monitoring device includes a transmission rotor disposed on a shaft side surface of a shaft of which the speed is to be measured and rotating with rotation of the shaft of which the speed is to be measured; an encoder having an input shaft, the input shaft of the encoder being connected to the transmission rotor and rotating with rotation of the transmission rotor; and a mounting bracket for securing the transmission rotor and the encoder to a position where they are to be mounted.

A rotation detection device to solve the above-described problems includes: accelerometers installed to be spaced apart from each other at predetermined pitches around a rotating shaft of a rotary machine, the accelerometers detecting rotation vibration of the rotary machine and outputting vibration signals; and a signal processing unit that acquires the vibration signals from the accelerometers. The signal processing unit includes: an installation information acquisition means for acquiring installation radii of the accelerometers with respect to the rotating shaft; an analysis processing means for acquiring frequency responses and coherences for the vibration signals; a determination means for determining whether or not the coherences are greater than a predetermined threshold value; and a rotation period calculation means for calculating a rotation period of the rotating shaft from the frequency, the phase difference, the predetermined pitch, and the installation radii.