Survey system with field calibration

A field calibration method for a survey system including a survey pole, a GNSS receiver with an IMU mounted to the survey pole, and a data collector, comprising:

• receiving a first set of measurements collected by the GNSS receiver while facing a first direction and with a tip of the survey pole at a user-selected location;
• receiving a second set of measurements collected by the GNSS receiver while facing a second direction offset from the first direction by a rotation angle and with the tip of the survey pole at the user-selected location;
• and
• with a calibration module, processing the first and second sets of measurements to calculate a set of corrections including at least one of a pitch correction, a roll correction, and a yaw correction,
• wherein the first and second sets of measurements include sensor attitude measurements provided by the IMU,
• wherein the set of corrections are calculated based on the sensor attitude measurements,
• wherein the sensor attitude measurements are used by the calibration module to determine a first position of the tip of the survey pole based on the first set of measurements and a second position of the tip of the survey pole based on the second set of measurements, and
• wherein the set of corrections define a true position of the tip of the survey pole during collection of the first and second sets of measurements based on the first and second positions of the tip of the survey pole.

A system for performing field calibration of a survey system, comprising:

• memory storing a first set of samples measured by a GNSS receiver with an embedded IMU while facing a first direction and with a tip of the survey pole at a user-selected location and further storing a second set of samples measured by the GNSS receiver while facing a second direction offset from the first direction by a rotation angle and with the tip of the survey pole at the user-selected location;
• a processor managing the memory;
• and
• a calibration module, run by the processor, processing the first and second sets of samples to calculate a set of corrections for use by the GNSS receiver when determining a position of the tip of the survey pole based on later-collected measurements,
• wherein the first and second sets of samples include sensor attitude measurements provided by the IMU,
• wherein the set of corrections are calculated based on the sensor attitude measurements,
• wherein the sensor attitude measurements are used by the calibration module to determine a first position of the tip of the survey pole based on the first set of samples and a second position of the tip of the survey pole based on the second set of samples, and
• wherein the set of corrections define a true position of the tip of the survey pole during collection of the first and second sets of samples based on the first and second positions of the tip of the survey pole.

A survey system adapted for field calibration, comprising:

• a survey pole extending linearly from a tip to a top end;
• a Global Navigation Satellite System (GNSS) receiver;
• mounting hardware attaching the GNSS receiver to the top end of the survey pole;
• and
• a calibration module processing first and second sets of data collected by the GNSS receiver with the GNSS receiver facing a first direction and a second direction, differing from the first direction, and with the tip of the survey pole at a point on a surface to calculate a correction to apply to measurements of the GNSS receiver when determining, with calibration to account for a bend in the survey pole or misalignments caused by use of the mounting hardware, a position of the tip of the survey pole,
• wherein the GNSS receiver comprises an embedded inertial measurement unit (IMU),
• wherein output of the IMU is used to determine when the GNSS receiver is oriented to face in the first and second directions,
• wherein the second direction is offset from the first direction by a rotation angle, and
• wherein the output of the IMU is used to determine when the survey pole has been rotated through the rotation angle.

A field calibration method for a survey system including a survey pole, a GNSS receiver with an IMU mounted to the survey pole, and a data collector, comprising:

• receiving a first set of measurements collected by the GNSS receiver while facing a first direction and with a tip of the survey pole at a user-selected location;
• receiving a second set of measurements collected by the GNSS receiver while facing a second direction offset from the first direction by a rotation angle and with the tip of the survey pole at the user-selected location;
• with a calibration module, processing the first and second sets of measurements to calculate a set of corrections including at least one of a pitch correction, a roll correction, and a yaw correction;
• and
• processing output of the IMU to measure rotation of the GNSS receiver and operating a display of the data collector to show the measured rotation of the GNSS receiver to indicate when the survey pole has been rotated through the rotation angle.

A field calibration method for a survey system including a survey pole, a GNSS receiver with an IMU mounted to the survey pole, and a data collector, comprising:

• receiving a first set of measurements collected by the GNSS receiver while facing a first direction and with a tip of the survey pole at a user-selected location;
• receiving a second set of measurements collected by the GNSS receiver while facing a second direction offset from the first direction by a rotation angle and with the tip of the survey pole at the user-selected location;
• and
• with a calibration module, processing the first and second sets of measurements to calculate a set of corrections including at least one of a pitch correction, a roll correction, and a yaw correction,
• wherein the processing of the first and second sets of measurements includes determining first and second mounting angles between an axis of the survey pole and first and second vectors orthogonal to attitude of the GNSS receiver measured by the IMU, and
• wherein the set of corrections correct for a non-zero value of the first and second mounting angles.

A system for performing field calibration of a survey system, comprising:

• memory storing a first set of samples measured by a GNSS receiver with an embedded IMU while facing a first direction and with a tip of the survey pole at a user-selected location and further storing a second set of samples measured by the GNSS receiver while facing a second direction offset from the first direction by a rotation angle and with the tip of the survey pole at the user-selected location;
• a processor managing the memory;
• and
• a calibration module, run by the processor, processing the first and second sets of samples to calculate a set of corrections for use by the GNSS receiver when determining a position of the tip of the survey pole based on later-collected measurements,
• wherein the calibration module processes output of the IMU to measure rotation of the GNSS receiver and, in response, operates a display to show the measured rotation of the GNSS receiver to indicate when the survey pole has been rotated through the rotation angle.

A system for performing field calibration of a survey system, comprising:

• memory storing a first set of samples measured by a GNSS receiver with an embedded IMU while facing a first direction and with a tip of the survey pole at a user-selected location and further storing a second set of samples measured by the GNSS receiver while facing a second direction offset from the first direction by a rotation angle and with the tip of the survey pole at the user-selected location;
• a processor managing the memory;
• and
• a calibration module, run by the processor, processing the first and second sets of samples to calculate a set of corrections for use by the GNSS receiver when determining a position of the tip of the survey pole based on later-collected measurements,
• wherein the processing of the first and second sets of samples includes determining first and second mounting angles between an axis of the survey pole and first and second vectors orthogonal to attitude of the GNSS receiver measured by the IMU, and
• wherein the set of corrections correct for a non-zero value of the first and second mounting angles.