Extending the Real-Time Kinematics Survey Method to Global Navigation Satellite System-Denied Areas Using a Low-Cost Inertial-Aided Positioning Pole

The global navigation satellite system (GNSS) real-time kinematics (RTK) survey method cannot be used in GNSS-denied areas largely due to signal block-age. In this work, we aim to extend high-precision RTK positioning capability to GNSS-denied areas via post-processing using an inertial-aided positioning pole that contains a inexpensive inertial measurement unit (IMU) chip and an RTK receiver. The positioning accuracy can be maintained at an acceptable level by using the pole as a walking stick with the pole periodically landing on the ground. Because the pole tip velocity is zero when it maintains contact with solid ground, lever-arm compensated zero-velocity updates (LA-ZUPTs) can be used to suppress errors in the inertial navigation system (INS) in GNSS-denied areas. Experimental results reveal that this method can be used to bridge up to a 60-meter GNSS gap to maintain sub-decimeter-level survey accuracy.