GNSS Antenna Rotation for Portable Direction Finding
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Solution Overview
Problem
Existing navigation systems face challenges in accurately determining a reference direction, particularly when high accuracy is required, as current methods involving GNSS systems require significant distance between measurement points or are impractical for portable and field-use applications.
Innovation Solution
A method and apparatus that utilize a rigid structure with a GNSS antenna and an angular measurement device separated by at least 0.5 meters, where the antenna rotates around the device, acquiring velocity and angular velocity data to determine a reference direction through the lever arm effect, allowing for accurate orientation in the North East Down frame of reference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS velocity information is used to find a directional reference by moving in a straight line, then direction accuracy can be improved, but the requirement for 1 km separation between ground positions makes the system impractical for portable and field-use applications
Solution Approach 1:
The patent transitions from requiring long spatial separation (1 km) to utilizing temporal separation through rotation. By rotating the antenna around the angular measurement device, the system creates a lever arm effect that converts angular motion into linear velocity measurements, achieving accurate direction determination without requiring large physical distances.
Solution Approach 2:
The system employs dynamic rotation of the antenna around the angular measurement device to create measurable velocity changes. This dynamic approach allows the use of small physical separations (0.5 meters or more) while still achieving accurate direction references through the lever arm effect, making the system portable and field-useable.
2Measurement precision
If the separation distance between GNSS antenna and angular measurement device is increased to improve accuracy, then direction reference accuracy improves, but device size and complexity increase
Solution Approach 1:
The patent uses dynamic rotation to amplify the measurement effect. By rotating the antenna around the angular measurement device, the system creates a lever arm effect where even small separations (0.5 meters or more) produce measurable velocity changes that can be used to determine accurate reference directions, eliminating the need for large physical separations.
Solution Approach 2:
The system employs periodic rotation of the antenna around the angular measurement device to create repeated velocity measurements. This periodic action allows the system to accumulate accurate direction reference data through multiple measurements, improving accuracy without requiring increased device size.
3Measurement precision
If repeated measurements and data processing like Kalman filters are used to reduce noise and increase accuracy, then measurement precision improves, but processing time and computational complexity increase
Solution Approach 1:
The patent employs Kalman filters and other data processing techniques that use feedback from repeated measurements to progressively improve the accuracy of the reference direction determination. The feedback mechanism allows the system to reduce noise and increase precision through iterative processing, balancing accuracy improvements with acceptable processing times.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables highly accurate reference direction determination using inexpensive equipment, providing a compact and portable solution for navigation systems, suitable for field use and time-pressured scenarios, while reducing noise and increasing accuracy through repeated measurements and data processing techniques like Kalman filters.
Implementation Method 1
providing a rigid structure having an antenna for a global navigation satellite system fixed at a first point thereof
Implementation Method 2
A gyroscope measures angular velocity (i.e. rotation rate) relative to its inertial position
Implementation Method 3
while rotating the rigid structure so as to cause rotational movement of the antenna around the sensitive axis of the angular measurement device
Implementation Method 4
using the velocity measurement data and the angular velocity measurement data to determine a reference direction for the angular measurement device
Data Source
AI summary
A method of determining a reference direction for an angular measurement device, comprising: providing a rigid structure having an antenna for a global navigation satellite system (GNSS) fixed at a first point thereof; fixing the angular measurement device to a second point on the rigid structure, separated from the first point by at least 0.5 meters; while rotating the rigid structure so as to cause rotational movement of the antenna around the sensitive axis, acquiring velocity measurement data from the GNSS and angular velocity measurement data from the angular measurement device; and using the velocity measurement data and the angular velocity measurement data to determine a reference direction for the angular measurement device.