GNSS Receiver Memory Squeezing for Search Capacity
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Solution Overview
Problem
GNSS receivers face inefficiencies in searching for visible satellites due to high costs and memory wastage from parallel searches and varying memory allocation requirements, which prolong the time-to-position fix.
Innovation Solution
A method involving sequential searches, memory squeezing, and dynamic allocation of concatenated free sections in the memory to optimize memory usage and reduce unnecessary searches, utilizing a correlator, memory, and memory squeezing unit with status and configuration registers to detect and allocate resources efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If parallel searches are performed using several correlators, then search capacity is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the search process into sequential phases (first search phase and second search phase) handled by a single correlator. The first phase searches for satellites in a first region, and the second phase searches for satellites in a second region. This segmentation allows the single correlator to handle multiple search tasks sequentially rather than requiring multiple correlators to work in parallel, thus improving search capacity without increasing device complexity.
Solution Approach 2:
The patent implements dynamic memory allocation where the correlator can be assigned to different search phases dynamically. The memory is allocated to store results from different searches, and the correlator transitions between processing different search phases. This dynamic approach allows a single correlator to perform multiple search functions that would traditionally require multiple static correlators, resolving the contradiction between search capacity and device complexity.
2Reliability
If memory is allocated for worst case search requirements, then search reliability is improved, but memory wastage increases
Solution Approach 1:
The patent implements dynamic memory allocation based on actual search requirements rather than fixed worst-case allocation. The memory is allocated to store results from the first search phase and second search phase as needed. When the first search phase completes, its memory is freed and reallocated for the second search phase. This dynamic approach ensures sufficient memory for reliability while avoiding wastage from over-allocation, as memory is only allocated when actually needed for current search operations.
Solution Approach 2:
The patent discards memory allocation for completed search phases and recovers it for subsequent search phases. After the first search phase completes, its dedicated memory is discarded/freed and then recovered/reallocated for the second search phase. This cycle of discarding and recovering memory ensures that memory is only held when necessary for active searches, preventing wastage while maintaining reliability through adequate allocation during each phase.
3Device complexity
If sequential searches are performed, then device complexity is reduced, but time required for position fix increases
Solution Approach 1:
The patent segments the satellite search process into distinct first search phase and second search phase, each handled by the single correlator. The first phase searches for satellites in a first region and the second phase searches for satellites in a second region. By segmenting the search space rather than searching all satellites sequentially in one phase, the patent reduces the time required while maintaining the simplicity of a single correlator architecture.
Solution Approach 2:
The patent performs preliminary actions by conducting the first search phase before the second search phase. The correlator completes the first search for satellites in the first region, stores the results, and only then proceeds to the second search for satellites in the second region. This preliminary completion of the first phase allows for efficient memory management and ensures that when the second phase begins, the correlator is already positioned and ready, minimizing total search time while maintaining sequential simplicity.
Data Source
AI summary
Enhancing search capacity of Global Navigation Satellite System (GNSS) receivers. A method for searching satellite signals in a receiver includes performing a plurality of searches sequentially. The method also includes storing a result from each search of the plurality of searches in a consecutive section of a memory. Further, the method includes detecting free sections in the memory. The method also includes concatenating the free sections in the memory to yield a concatenated free section. Moreover, the method includes allocating the concatenated free section for performing an additional search.