A method can include receiving sensor data, receiving satellite observations, determining a positioning solution (e.g., PVT solution, PVA solution, kinematic parameters, etc.) based on the sensor data and the satellite observations. A system can include a sensor, a GNSS receiver, and a processor configured to determine a positioning solution based on readings from the sensor and the GNSS receiver.

A method can include receiving sensor data, receiving satellite observations, determining a positioning solution (e.g., PVT solution, PVA solution, kinematic parameters, etc.) based on the sensor data and the satellite observations. A system can include a sensor, a GNSS receiver, and a processor configured to determine a positioning solution based on readings from the sensor and the GNSS receiver.

A method can include receiving sensor data, receiving satellite observations, determining a positioning solution (e.g., PVT solution, PVA solution, kinematic parameters, etc.) based on the sensor data and the satellite observations. A system can include a sensor, a GNSS receiver, and a processor configured to determine a positioning solution based on readings from the sensor and the GNSS receiver.

A method can include receiving sensor data, receiving satellite observations, determining a positioning solution (e.g., PVT solution, PVA solution, kinematic parameters, etc.) based on the sensor data and the satellite observations. A system can include a sensor, a GNSS receiver, and a processor configured to determine a positioning solution based on readings from the sensor and the GNSS receiver.

A distance measurement apparatus includes a calculation unit configured to calculate, based on phase information acquired by two distance measurement units at least one of which is movable, a distance between the two distance measurement units. One of the two distance measurement units includes an RSSI estimation unit configured to estimate, from respective three receiving signal intensities of three first carrier signals or respective three receiving signal intensities of three second carrier signals, the receiving signal intensity of a frequency having an average value, and a fading correction value calculation unit configured to calculate a fading correction value for the distance from the receiving signal intensity of a lowest frequency and the receiving signal intensity of a highest frequency. The calculation unit calculates the distance using a phase detection result obtained by receiving the three first carrier signals and the three second carrier signals and the fading correction value.

A position/posture computing section determines that an azimuth of an upper swing structure calculated at a GNSS receiver is of low quality when at least one of a posture angle of the upper swing structure acquired at a machine-body IMU and a posture angle of a front work implement acquired at a boom IMU is equal to or larger than a threshold value, executes a bias removal computation on the basis of the quality of the azimuth and the azimuth of the upper swing structure calculated at the GNSS receiver, calculates a corrected azimuth of the upper swing structure on the basis of the azimuth of the upper swing structure calculated at the GNSS receiver, and an angular velocity of the upper swing structure from which a gyro bias has been removed, and computes a three-dimensional position and posture of the front work implement by using the corrected azimuth.

A position/posture computing section determines that an azimuth of an upper swing structure calculated at a GNSS receiver is of low quality when at least one of a posture angle of the upper swing structure acquired at a machine-body IMU and a posture angle of a front work implement acquired at a boom IMU is equal to or larger than a threshold value, executes a bias removal computation on the basis of the quality of the azimuth and the azimuth of the upper swing structure calculated at the GNSS receiver, calculates a corrected azimuth of the upper swing structure on the basis of the azimuth of the upper swing structure calculated at the GNSS receiver, and an angular velocity of the upper swing structure from which a gyro bias has been removed, and computes a three-dimensional position and posture of the front work implement by using the corrected azimuth.

The present disclosure measures an attitude even when an antenna cannot receive a positioning signal a receiver cannot acquire positioning information from the signal. An attitude measuring device includes: antennas, receivers, and processing circuitry. The antennas receive positioning signals and output reception signals, respectively. There are four or more antennas. The receivers are provided for the respective antennas and output positioning data containing a carrier phase based on the reception signals. The processing circuitry calculates the position of each antenna using the relevant positioning data, estimates a reception state of the positioning data based on the calculated position, and selects between a first attitude calculation mode using four or more positioning data with a good reception state and a second attitude calculation mode using three or less positioning data with the good reception state. The processing circuitry calculates an attitude using the selected attitude calculation mode.

The present disclosure measures an attitude even when an antenna cannot receive a positioning signal a receiver cannot acquire positioning information from the signal. An attitude measuring device includes: antennas, receivers, and processing circuitry. The antennas receive positioning signals and output reception signals, respectively. There are four or more antennas. The receivers are provided for the respective antennas and output positioning data containing a carrier phase based on the reception signals. The processing circuitry calculates the position of each antenna using the relevant positioning data, estimates a reception state of the positioning data based on the calculated position, and selects between a first attitude calculation mode using four or more positioning data with a good reception state and a second attitude calculation mode using three or less positioning data with the good reception state. The processing circuitry calculates an attitude using the selected attitude calculation mode.

Systems and methods for estimating attitude and heading are provided. The systems and methods utilize carrier phase single difference (CSD) measurements or carrier phase double difference (CDD) measurements and a validation test for CSD or CDD measurement residuals. The systems and methods include applying a wrapping function with limit of ±half of the GNSS carrier signal wavelength to CSD or CDD measurement residuals to generate refined CSD or CDD measurement residuals and validating the refined CSD or CDD measurement residuals variance to determine valid CSD or CDD measurements. By using the validated CSD and CDD measurements, the systems and methods enable low grade hybrid inertial navigation systems to estimate attitude and heading with integrity and without a magnetometer or the need for integer ambiguity resolution even during the static or steady phases of flight/operation.