Position determination using iterative range reduction

A method for determining a position of a device using a set of nodes, referred to as anchor nodes, the method comprising:

• providing a set of initial ranges in time or space between the set of anchor nodes and the device;
• executing one or more times a position determination operation, the position determination operation comprising:
• determining a first set of initial ranges;
• estimating a first position of the device using the first set of initial ranges and positions of the corresponding anchor nodes;
• estimating a second position of the device using a second set of initial ranges and positions of the corresponding anchor nodes;
• providing either the first position or the second position as the device's position based on fulfillment of an estimation position improvement criterion;
• wherein the second set of initial ranges is the first set of initial ranges with a predefined reduction in the number of initial ranges;
• the predefined reduction being a removal of one initial range, wherein the first set of initial ranges is the set of initial ranges in the initial execution of the position determination operation or otherwise is the second set of initial ranges of a last execution of the position determination operation;
• wherein the position determination operation is executed until the provision of the position.

A non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform:

• providing a set of initial ranges in time or space between the set of anchor nodes and the device;
• executing one or more times a position determination operation, the position determination operation comprising:
• determining a first set of initial ranges;
• estimating a first position of the device using the first set of initial ranges and positions of the corresponding anchor nodes;
• estimating a second position of the device using a second set of initial ranges and positions of the corresponding anchor nodes;
• providing either the first position or the second position as the device's position based on fulfillment of an estimation position improvement criterion;
• wherein the second set of initial ranges is the first set of initial ranges with a predefined reduction in the number of initial ranges;
• the predefined reduction being a removal of one initial range, wherein the first set of initial ranges is the set of initial ranges in the initial execution of the position determination operation or otherwise is the second set of initial ranges of a last execution of the position determination operation;
• wherein the position determination operation is executed until the provision of the position.