Walking stick navigator for position determination
First Claim
1. A walking stick navigator (WSN) on a staff having a lower end, the WSN being carried by a surveyor and comprising:
- an Aided Inertial Navigation System (AINS) coupled to the staff, the AINS having an IMU providing inertial outputs, 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 digital computer running a position measurement program solving a position aiding algorithm responsive to the IMU outputs and the contact signal, the position measurement program providing an aiding signal to the AINS.
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Abstract
A walking stick navigator (WSN) apparatus and process comprises an aided INS (AINS) on a staff assembly similar in operation and appearance to a GPS survey instrument. However, 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.
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Citations
19 Claims
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1. A walking stick navigator (WSN) on a staff having a lower end, the WSN being carried by a surveyor and comprising:
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an Aided Inertial Navigation System (AINS) coupled to the staff, the AINS having an IMU providing inertial outputs, 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 digital computer running a position measurement program solving a position aiding algorithm responsive to the IMU outputs and the contact signal, the position measurement program providing an aiding signal to the AINS. - View Dependent Claims (2, 3, 4, 5)
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6. A walking stick navigator (WSN) apparatus 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 a start of a stride, and pivoting the staff assembly around the stationary point in the direction of surveyor movement, the surveyor lifting the staff assembly and repositioning the lower end of the staff assembly to a stationary point in the direction of surveyor movement at the conclusion of the stride, a 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 stationary interval signals characterizing each successive stationary interval, and a digital computer coupled to be responsive to AINS output signals and to the stationary interval signals running a program solving a position aiding algorithm providing at least one aiding input to the AINS for each successive stationary interval. - View Dependent Claims (7, 8, 9, 10, 11)
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12. The WSN of claim 111 wherein the position aiding algorithm further comprises:
a velocity measurement program responsive to the AINS output signals for providing a relative IMU velocity vector {overscore (v)}GR-IMU to the AINS during a portion of each step for each respective stationary interval to control the position error drift. - View Dependent Claims (13, 14, 15)
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16. A walking stick navigator (WSN) on a shaft assembly, a surveyor carrying the shaft assembly and positioning a shaft lower end to be in contact with the ground in front of the surveyor marking the start of
a stationary interval, the surveyor pivoting the shaft assembly in the direction of his movement, and raising the shaft assembly interrupting the shaft lower end being in contact with the ground at the conclusion of each step marking the end of the stationary interval, the WSN comprising: -
an AINS having an IMU providing output signals developed from the outputs of a plurality of inertial sensors, a digital computer running a position measurement aiding program, the digital computer being responsive to the AINS output signals for providing a position increment measurement vector {overscore (z)}SNV-PP to the AINS during a portion of each step for each respective stationary interval to control position error drift. - View Dependent Claims (17, 18, 19)
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Specification