Position measuring method, position measuring apparatus, and position measuring system

A position measuring method for measuring a positon of a target, the method comprising:

• acquiring, using a first imaging device mounted on a first mobile object, a first image of the target from a first location;
• measuring, based on the first image, a first orientation of the target as viewed from the first location and a first orientation angular velocity of the target as viewed from the first location;
• transmitting the first orientation and the first orientation angular velocity to a calculator;
• acquiring, using a second imaging device mounted on a second mobile object, a second image of the target from a second location;
• measuring, based on the second image, a second orientation of the target as viewed from the second location and a second orientation angular velocity of the target as viewed from the second location;
• and
• transmitting the second orientation and the second orientation angular velocity to the calculator,
• wherein the calculator is configured to execute:
• correcting the first orientation and the second orientation respectively to the first orientation that is based on a first time at which the calculator has received the first orientation and the first orientation angular velocity and to the second orientation that is based on a second time at which the calculator has received the second orientation and the second orientation angular velocity, respectively on a basis of the first orientation, the first orientation angular velocity, and a first transmission time of transmitting a first signal from the first mobile object to the calculator and on a basis of the second orientation, the second orientation angular velocity, and a second transmission time of transmitting a second signal from the second mobile object to the calculator;
• and
• calculating an estimated position of the target, on a basis of the corrected first orientation as viewed from the first location and the corrected second orientation as viewed from the second location.

A position measuring apparatus mounted on one or more mobile objects and configured to measure a position of a target, the apparatus comprising:

• an imaging device mounted on a mobile object, the imaging device being configured to acquire a first image of the target from a first location and a second image of the target from a second location after acquiring the first image, the first location and the second location being different from each other;
• and
• a controller configured to
• measure, 1) based on the first image, a first orientation of the target as viewed from the first location, and 2) based on the second image, a second orientation of the target as viewed from the second location,
• calculate an estimated orientation of the target that is as viewed from the first location and at a time at which the second image is acquired, through correcting the first orientation based on a difference between a time at which the first image is acquired and the time at which the second image is acquired, and
• calculate, based on the second orientation and the estimated orientation, an estimated position of the target that is as viewed from the first location and at a time at which the second image is acquired.

A position measuring system configured to measure a position of a target, the system comprising:

• a first mobile object having a first imaging device, the first imaging device being configured to acquire a first image of the target from a first location;
• a second mobile object having a second imaging device, the second imaging device being configured to acquire a second image of the target from a second location;
• and
• a calculator configured to transmit signals between the calculator and the first mobile object and between the calculator and the second mobile object, the calculator being configured to
• measure, on a basis of the first image, a first orientation of the target as viewed from the first location and a first distance to the target from the first location, to thereby acquire a first position of the target determined at the first location,
• measure, on a basis of the second image, a second orientation of the target as viewed from the second location and a second distance to the target from the second location, to thereby acquire a second position of the target determined at the second location,
• calculate a time at which the first image is acquired at the first location and a time at which the second image is acquired at the second location, respectively on a basis of a time at which the calculator has received the first position and a time at which the calculator has received the second position, and
• calculate a middle position between the first position determined at the first location and the second position determined at the second location, and a middle time between the time at which the first image is acquired at the first location and the time at which the second image is acquired at the second location, the middle position being calculated as an estimated position of the target, the middle time being a time corresponding to the middle position.