Removable GNSS Antenna for Pointing System Calibration
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Solution Overview
Problem
Existing pointing systems face challenges in accurately calibrating to absolute north and pitch, particularly in environments where GNSS signals are unavailable due to interference or cost constraints, and rely on expensive high-precision inertial sensors.
Innovation Solution
A pointing system utilizing two GNSS antennas with a fixed baseline, where one antenna is removable after calibration, allowing for accurate initial alignment using GNSS signals and subsequent operation without GNSS signals, leveraging low-cost sensors for cost-effectiveness and mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-precision inertial sensors are used for calibration, then alignment accuracy is improved, but system cost and complexity increase
Solution Approach 1:
The patent introduces a removable second GNSS antenna as an intermediary calibration aid. This temporary component enables accurate alignment by providing additional GNSS signal data during the calibration phase, eliminating the need for expensive inertial sensors. After calibration, the second antenna is removed, leaving a simple system without complex inertial measurement units.
2Measurement precision
If GNSS signals are used for calibration, then alignment accuracy is improved, but system cost increases
Solution Approach 1:
The patent performs alignment calibration in advance using GNSS signals before the system enters its operational phase. The second GNSS antenna is temporarily attached during this preliminary calibration action to establish accurate north and pitch references. Once calibration is complete, the antenna is removed, and the system operates without requiring continuous GNSS signals or additional expensive components.
3Measurement precision
If a fixed baseline between GNSS antennas is used, then attitude determination accuracy is improved, but system size increases
Solution Approach 1:
The patent makes the second GNSS antenna dynamically removable rather than permanently fixed to the system. During calibration, the antenna is attached to establish a fixed baseline for accurate attitude determination. After calibration, the antenna is removed, allowing the system to operate in a compact form without the permanent presence of additional antenna mounting structures.
Data Source
AI summary
An example pointing system includes a sensor that measures change in angular position, a first GNSS antenna, and a second GNSS antenna mounted to a rigid body that is removable from the pointing system after calibration of the sensor. The GNSS antennas have a fixed, known baseline. The pointing system includes at least one GNSS receiver with first and second RF inputs respectively coupled to the GNSS antennas. The at least one GNSS receiver includes respective paths to process GNSS signals received from the first and second RF inputs. The pointing system includes at least one processor, communicatively coupled to the sensor and receiver, configured to: determine initial attitude of the pointing system based on the processed GNSS signals; calibrate the sensor using the determined initial attitude; determine a pointing solution for the pointing system based on measurements from the calibrated sensor without GNSS signals from second GNSS antenna.