A method of estimating a location of a user terminal is provided. It is based on a difference between a true north and a magnetic north that may estimate a location of a user terminal on a magnetic field map based on a difference between a true north and a magnetic north corresponding to each location of the magnetic field map, and the user terminal thereof.

Dive computers in accordance with embodiments of the invention are disclosed that store information concerning a dive site. The stored information can be accessed during the dive to provide information concerning such things as points of interest and/or hazards. One embodiment of the invention includes a processor, memory connected to the processor, a pressure transducer connected to the processor and configured to measure depth, and a display connected to the processor. In addition, the memory contains factual information concerning a dive site, and the processor is configured to display at least a portion of the stored factual information concerning the dive site via the display.

Dive computers in accordance with embodiments of the invention are disclosed that store information concerning a dive site. The stored information can be accessed during the dive to provide information concerning such things as points of interest and/or hazards. One embodiment of the invention includes a processor, memory connected to the processor, a pressure transducer connected to the processor and configured to measure depth, and a display connected to the processor. In addition, the memory contains factual information concerning a dive site, and the processor is configured to display at least a portion of the stored factual information concerning the dive site via the display.

A method including operating a vehicle in a medium. The vehicle is subject to advection due to movement of the medium. The method also includes measuring, using a navigation system, positions of a vehicle over time. The method also includes measuring, using a directional sensor, a course-through-medium over the time. The method also includes calculating, using the positions and the course-through-medium, a variation of a speed-over-ground of the vehicle over the time as a function of the course-through-medium over the time. The method also includes concurrently estimating, using the variation, 1) an average speed-through-medium for the vehicle over the time, and 2) an advection rate of the medium, and 3) an advection direction of the medium.

A method including operating a vehicle in a medium. The vehicle is subject to advection due to movement of the medium. The method also includes measuring, using a navigation system, positions of a vehicle over time. The method also includes measuring, using a directional sensor, a course-through-medium over the time. The method also includes calculating, using the positions and the course-through-medium, a variation of a speed-over-ground of the vehicle over the time as a function of the course-through-medium over the time. The method also includes concurrently estimating, using the variation, 1) an average speed-through-medium for the vehicle over the time, and 2) an advection rate of the medium, and 3) an advection direction of the medium.

The present disclosure relates to a ranging method and a ranging system, the ranging method includes using a first laser emitting portion of a laser emitting device to emit a vertical laser beam rotating in a vertical plane at a first rotation speed; calculating a time difference between the vertical laser beam passing through a first optical detection component and a second optical detection component by using the first optical detection component and the second optical detection component on a laser receiving device at least partially on the same vertical plane, wherein a distance between the two optical detection components is a first spacing; and calculating a first distance between the laser emitting device and the laser receiving device based on the first rotation speed, the first spacing, and the time difference.

The present disclosure relates to a ranging method and a ranging system, the ranging method includes using a first laser emitting portion of a laser emitting device to emit a vertical laser beam rotating in a vertical plane at a first rotation speed; calculating a time difference between the vertical laser beam passing through a first optical detection component and a second optical detection component by using the first optical detection component and the second optical detection component on a laser receiving device at least partially on the same vertical plane, wherein a distance between the two optical detection components is a first spacing; and calculating a first distance between the laser emitting device and the laser receiving device based on the first rotation speed, the first spacing, and the time difference.

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.

A network of scopes, including one or more lead scopes and one or more follower scopes, is provided to allow scope operators of the respective scopes to track the same presumed target. A lead scope locates a target and communicates target position data of the presumed target to the follower scope. The follower scope uses the target position data and its own position data to electronically generate indicators for use to prompt the operator of the follower scope to make position movements so as to re-position the follower scope from its current target position to move towards the target position defined by the target position data received from the lead scope.

A network of scopes, including one or more lead scopes and one or more follower scopes, is provided to allow scope operators of the respective scopes to track the same presumed target. A lead scope locates a target and communicates target position data of the presumed target to the follower scope. The follower scope uses the target position data and its own position data to electronically generate indicators for use to prompt the operator of the follower scope to make position movements so as to re-position the follower scope from its current target position to move towards the target position defined by the target position data received from the lead scope.