Cloud-Offloaded GNSS Positioning for Mobile IoT Energy Savings
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Solution Overview
Problem
Existing GNSS positioning methods for IoT devices face challenges with accuracy due to unreliable power measurements and high energy consumption, especially in urban environments, and require complex computational resources, making them unsuitable for mobile objects.
Innovation Solution
A cloud-offloaded GNSS positioning method that time-stamps code phases or samples using a network clock, allowing a computing server to estimate pseudoranges and calculate the object's position without requiring local time-stamping, suitable for both mobile and non-mobile objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GNSS positioning is implemented on mobile IoT devices, then positioning capability is provided, but energy consumption increases significantly
Solution Approach 1:
The patent extracts the computationally intensive GNSS processing tasks from the mobile IoT device and relocates them to a remote server. The device only performs simple signal reception and time-stamping, while the server handles satellite signal processing, pseudorange calculation, and position determination. This extraction resolves the contradiction by maintaining positioning capability while dramatically reducing energy consumption on the mobile device.
Solution Approach 2:
The patent introduces a remote server as an intermediary between the mobile IoT device and the GNSS positioning system. This intermediary handles the complex computational tasks that would otherwise burden the mobile device, enabling positioning capability without requiring the device to perform energy-intensive processing operations.
2Measurement precision
If local time-stamping is implemented in the GNSS receiver, then positioning accuracy is improved, but device complexity increases
Solution Approach 1:
The patent uses a network time-stamp clock as an intermediary to provide accurate time-stamping without requiring the mobile device to implement complex local timing mechanisms. The remote server, synchronized with network time standards, provides the time-stamp information needed for accurate positioning while keeping the device architecture simple.
Solution Approach 2:
Instead of implementing a complex local time-stamping system in the mobile device, the patent uses a simplified approach where the device merely records the time-stamp information provided by the network. The actual time-keeping function is copied and executed by the remote server, which has access to synchronized network time sources.
3Reliability
If mobile objects are positioned using conventional GNSS methods, then positioning is achieved, but computational resources required become too large for mobile devices
Solution Approach 1:
The patent extracts all computationally intensive GNSS processing operations from the mobile device and relocates them to a remote server. The device only performs simple signal reception and time-stamping, while the server handles satellite signal processing, pseudorange calculation, and position determination. This extraction resolves the contradiction by maintaining positioning capability while dramatically reducing computational requirements on the mobile device.
Solution Approach 2:
The patent segments the GNSS positioning system into two distinct parts: a simple mobile device component for signal reception and a powerful remote server component for computational processing. This segmentation allows the mobile device to remain simple and energy-efficient while the server handles all computationally intensive tasks.
4Use of energy by moving object
If cloud-offloaded GNSS processing is implemented, then energy consumption is reduced, but positioning accuracy may be compromised without local time-stamping
Solution Approach 1:
The patent introduces a network time-stamp clock as an intermediary that provides accurate time information to the remote server. This intermediary ensures that even though the mobile device performs minimal local processing, the positioning accuracy is maintained through precise time-stamping of the signal reception data.
Solution Approach 2:
The patent implements a feedback mechanism where the remote server receives time-stamped data from the mobile device, processes the GNSS signals, and calculates the position. The system ensures accuracy by continuously synchronizing the time-stamp clock with network time standards and using the precise time information in the position calculation feedback loop.
Data Source
AI summary
A cloud-offloaded GNSS (CO-GNSS) positioning method for locating a connected object. The signal received by the object is translated to an intermediate frequency before being sampled. The connected object acquires the satellites and estimates the code phases, which are transmitted to the server and then time-stamped. The server then determines a set of candidate points of a mesh network seeing the same set of satellites at the time-stamping instant of the packet, and then calculates for each candidate point and each possible transmission time the differences in pseudorange between the satellites and this point. It deduces from same a likelihood metric as a function of the difference between the differences in pseudorange corresponding to the code phases estimated for the object and those calculated for each candidate point. The candidate point maximising the likelihood metric provides a rough estimate of the position of the connected object.