Pseudolite Positioning Using Disjoint Satellite Codes
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Solution Overview
Problem
Existing pseudolite positioning systems cannot operate autonomously and continuously between constrained and open zones without assistance, and they require specific receivers to differentiate between pseudolite and satellite signals, making it impossible for standard receivers to determine their position without initial knowledge or assistance data.
Innovation Solution
A pseudolite positioning system that uses a constellation of satellites with disjoint visibility subsets, assigning pseudolites spreading codes from non-visible satellites, allowing standard receivers to autonomously detect and decode pseudolite signals, and switch between operating modes seamlessly between constrained and open zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pseudolites use spreading codes of visible satellites, then standard receivers can acquire signals, but receivers cannot differentiate between pseudolite and satellite signals to determine position autonomously
Solution Approach 1:
The patent applies copying by having pseudolites use spreading codes that are copies of satellite codes. This allows standard receivers to acquire pseudolite signals as if they were satellite signals, while the receiver's autonomous detection capability distinguishes them through geometric validation of signal coherence with visible satellite positions.
2Adaptability or versatility
If pseudolite systems operate in constrained zones, then positioning is available indoors, but seamless transition to open zones and cold starts without assistance are impossible
Solution Approach 1:
The patent applies dynamics by making the receiver's operating mode dynamic rather than static. The receiver autonomously transitions between assisted and unassisted modes based on real-time signal acquisition success. In unassisted mode, it uses geometric validation to verify pseudolite signals match visible satellite geometry, enabling seamless operation across zone transitions and cold starts without external assistance.
Solution Approach 2:
The patent applies feedback through the receiver's autonomous monitoring of signal acquisition results. When satellites are not visible or signals cannot be acquired, the receiver switches to unassisted mode and uses geometric feedback validation to confirm pseudolite positions, ensuring continuous positioning reliability across different operational environments.
3Reliability
If specific receivers are designed for pseudolite acquisition, then positioning works in constrained zones, but standard receivers cannot operate without assistance data
Solution Approach 1:
The patent applies universality by enabling standard multi-functional receivers to operate in both satellite and pseudolite modes. The receiver maintains its standard satellite acquisition capabilities while adding autonomous geometric validation functionality, allowing it to use pseudolite signals without requiring specialized hardware or assistance data, thus achieving positioning availability across diverse environments.
4Ease of operation
If pseudolites use satellite spreading codes, then signal acquisition is simplified, but receivers cannot autonomously detect pseudolite signals without assistance data
Solution Approach 1:
The patent applies self-service by enabling the receiver to autonomously detect and validate pseudolite signals using its own computational resources and geometric knowledge of visible satellite positions. The receiver independently determines whether acquired signals originate from pseudolites by checking geometric coherence, eliminating dependence on external assistance data while maintaining ease of signal acquisition through compatible spreading codes.
Data Source
Figure 1
AI summary
The subject of the present invention is a system for positioning an object in a constrained zone, comprising: - a set of pseudolites distributed in said constrained zone and each exhibiting a spreading code corresponding to the spreading code of a satellite belonging to a constellation of satellites of a satellite navigation system, said constellation of satellites comprising at least one first set of satellites (S1) and one second set of satellites (S2)of disjoint visibility, - and a receiver situated on the object to be located, the pseudolites being distributed in the constrained zone in such a way that at any point of the constrained zone, it is possible for the receiver of the object to acquire the positioning signals of at least two pseudolites exhibiting spreading codes corresponding, for the one, to a satellite of the first set (S1), and, for the other, to a satellite of the second set (S2) in such a way that the receiver receiving these positioning signals detects the impossibility of them being signals emitted by satellites of the constellation of satellites and consequently determines in a totally autonomous manner that it is receiving positioning signals emitted by pseudolites.