Satellite Signal Receiver DOP Index Calculation
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Solution Overview
Problem
Global navigation satellite systems face challenges in selecting the most precise satellite signals for positioning due to variations in modulation types and transmission powers, leading to inconsistencies in pseudorange estimation and positioning accuracy.
Innovation Solution
A method is introduced to calculate a DOP index by applying pseudorange weights based on tracking error standard deviation (TESD) to a DOP matrix, allowing for the selection of satellite signal combinations with improved precision, incorporating signals from GPS, Galileo, and GLONASS systems, ensuring consistent carrier-to-noise ratio (CNR) across different satellite signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If satellite signals from different GNSS systems with different modulation types and transmission powers are used for positioning, then the quantity of available satellite signals increases, but the measurement precision of pseudorange estimation deteriorates due to inconsistencies across different signal types
Solution Approach 1:
The patent applies different weights to pseudorange measurements from different satellite signals based on their specific characteristics (modulation type, transmission power, CNR). This local quality adjustment ensures that each signal contributes appropriately to the positioning calculation according to its individual precision level, resolving the contradiction between using diverse signals and maintaining measurement consistency
Solution Approach 2:
The patent introduces weight parameters (w_i) that are calculated based on carrier-to-noise ratio (CNR) and tracking error standard deviation (TESD). By changing the parameter of pseudorange measurement precision through these weights, the system can accurately process signals with different qualities while maintaining overall measurement precision across multiple GNSS systems
2Device complexity
If uniform weight is applied to all satellite signals regardless of their signal characteristics, then the device complexity is reduced, but the positioning accuracy deteriorates due to ignoring signal quality differences
Solution Approach 1:
The patent performs preliminary calculations of weight parameters (w_i) based on CNR and TESD before the actual positioning computation. This preliminary action prepares the signal quality assessment in advance, allowing the main positioning algorithm to use pre-computed weights without significant additional complexity, thus maintaining positioning accuracy while limiting complexity increase
Solution Approach 2:
The patent introduces weight parameters as an intermediary between raw satellite signals and the positioning calculation. These weights mediate the contribution of each signal based on its quality, allowing uniform processing methodology while accounting for signal differences, thus improving accuracy without proportionally increasing system complexity
Data Source
AI summary
There is provided a method of selecting a satellite for positioning in a global navigation satellite system, which includes: receiving satellite signals from satellites that a receiver can receive; calculating DOP where pseudorange weight is applied for each of satellite signal combinations including at least four or more of the satellite signals by the receiver; and selecting a satellite signal combination having the smaller DOP than a standard in the satellite signal combinations by the receiver.