Walking stick navigator for position determination
First Claim
1. A walking stick navigator (WSN) apparatus and process comprising:
- a staff assembly having a lower end and a top end, the staff assembly being carried by a surveyor moving along a path to be surveyed, the surveyor positioning the lower end of the staff assembly at a stationary point on the ground at the start of a stride, and pivoting the staff assembly around the stationary point substantially in the direction of surveyor movement, the surveyor lifting the staff assembly and repositioning the lower end of the staff assembly to a further stationary point in the direction of surveyor movement at the conclusion of the stride, the sequence being repeated with each successive stride interval, an Aided Inertial Navigation System (AINS), coupled to and aligned on the staff assembly, the AINS system providing output signals comprising position, velocity and platform angle signals, a switch means coupled to the lower end of the staff assembly for providing a stationary interval signals characterizing each successive stationary interval, and an input process coupled to be responsive to AINS output signals and to the stationary interval signals for providing at least one aiding input to the AINS for each successive stationary interval.
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Accused Products
Abstract
A walking stick navigator (WSN) apparatus and process comprises an aided INS (AINS) on a staff assembly that has the “look and feel” of a GPS survey instrument. When GPS is available, the AINS is aided by GPS data, and the surveyor manipulates the staff assembly like a standard GPS survey instrument. When GPS is not available due to signal obstruction, the surveyor manipulates the staff assembly as a walking stick. A switch means coupled to the lower end of the staff assembly provides a stationary interval signal when the surveyor plants and holds the WSN on the ground while walking. An input process is coupled to the AINS output signals and to the stationary interval signals and provides at least one aiding input signal to the AINS for each successive stationary interval, thereby allowing the AINS to control its velocity error and position drift during a GPS outage.
66 Citations
25 Claims
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1. A walking stick navigator (WSN) apparatus and process comprising:
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a staff assembly having a lower end and a top end, the staff assembly being carried by a surveyor moving along a path to be surveyed, the surveyor positioning the lower end of the staff assembly at a stationary point on the ground at the start of a stride, and pivoting the staff assembly around the stationary point substantially in the direction of surveyor movement, the surveyor lifting the staff assembly and repositioning the lower end of the staff assembly to a further stationary point in the direction of surveyor movement at the conclusion of the stride, the sequence being repeated with each successive stride interval, an Aided Inertial Navigation System (AINS), coupled to and aligned on the staff assembly, the AINS system providing output signals comprising position, velocity and platform angle signals, a switch means coupled to the lower end of the staff assembly for providing a stationary interval signals characterizing each successive stationary interval, and an input process coupled to be responsive to AINS output signals and to the stationary interval signals for providing at least one aiding input to the AINS for each successive stationary interval. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A walking stick navigator (WSN) formed on a staff assembly having a lower end terminating in a spike, and a top end, a surveyor supporting the staff assembly while walking, the surveyor positions the staff assembly lower end to be in contact with the ground at a fixed point in front of the surveyor at the beginning of a step marking the start of a stationary interval, the surveyor pivoting the staff assembly about the fixed point in the direction of his movement, and raising the staff assembly to interrupt the shaft lower end contact with the ground at the fixed point at the conclusion of each step marking the end of the stationary interval, the WSN comprising:
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an AINS having an IMU providing output signals developed at least partially from the outputs of a plurality of inertial sensors, a position measurement process responsive to the AINS output signals for providing a position increment measurement vector to the AINS during a portion of each step for each respective stationary interval to control position error drift. - View Dependent Claims (12, 13, 14)
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15. A walking stick navigator (WSN) method comprising the steps of:
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forming a WSN staff assembly having a lower end, a hand hold mid region and a top end, positioning an AINS having a Kalman filter on the staff assembly, positioning a switch means for signaling when the lower end of the staff assembly is stationary and in contact with the ground and for sending a contact signal to the AINS, the contact signal defining each interval during which the lower end of the staff assembly is in contact with the ground, supporting the staff assembly by holding the hand hold mid region, while walking, positioning the staff assembly lower end to be in contact with the ground at a fixed point in front of the surveyor at the beginning of a step marking the start of a stationary interval, the surveyor rotating the staff assembly about the fixed point in the direction of his movement, and raising the staff assembly to interrupt the staff assembly lower end contact with the ground at the fixed point at the conclusion of each step marking the end of the stationary interval, coupling the contact signal to the AINS to define the term of each respective stationary interval to the AINS, calculating aiding information for the AINS during and for the contact signal interval in response to contemporaneous IMU inertial measurements and the position of the AINS on the staff assembly. - View Dependent Claims (16, 17, 18, 19)
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20. A walking stick navigator (WSN) formed on a staff assembly having a lower end, the staff assembly being carried by a surveyor, the WSN comprising
an AINS coupled to the staff a switch coupled to the lower end to provide a contact signal indicating when the lower end of the staff assembly is stationary, the contact signal defining the duration of a stationary interval, a position measurement process using a computer running a program solving a position aiding algorithm responsive to the contact signal, the position measurement process providing an aiding signal to an AINS coupled to the staff assembly.
Specification