Shared ROM Architecture for Multi-Channel PRN Code Generation

Solution Overview

Problem

Generating pseudo-random noise (PRN) codes for multiple tracking channels and satellite-based navigation systems is computationally intensive, requiring significant silicon area and power consumption due to the need for multiple read-only memories (ROMs) to store Legendre sequences.

Innovation Solution

A shared read-only memory (ROM) architecture is used to generate PRN codes, allowing simultaneous access to Legendre sequences for multiple tracking channels and satellite systems, reducing the number of ROMs required and optimizing power consumption and silicon area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple read-only memories (ROMs) are used to store Legendre sequences for multiple tracking channels, then PRN code generation capability is improved, but silicon area and power consumption increase

Engineering Contradiction:

ImprovePRN code generation capabilityVSAvoidsilicon area

Core Design Contradiction:

ProductivityVSArea of stationary object

Solution Approach 1:

Multiple separate ROMs storing Legendre sequences are merged into a single shared ROM. The patent implements a unified memory structure where all tracking channels access the same ROM resource, eliminating redundant storage of identical code sequences across multiple memory devices.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The shared ROM is designed to serve multiple tracking channels simultaneously through time-multiplexed access. The single ROM structure performs the function of multiple ROMs by serving different tracking channels at different time slots, achieving multi-functionality without requiring multiple physical memory devices.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Productivity

If multiple read-only memories (ROMs) are used to store Legendre sequences for multiple tracking channels, then PRN code generation capability is improved, but power consumption increases

Engineering Contradiction:

ImprovePRN code generation capabilityVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSUse of energy by stationary object

Solution Approach 1:

Multiple separate ROMs storing Legendre sequences are merged into a single shared ROM. The patent implements a unified memory structure where all tracking channels access the same ROM resource, eliminating redundant storage of identical code sequences across multiple memory devices.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The shared ROM is designed to serve multiple tracking channels simultaneously through time-multiplexed access. The single ROM structure performs the function of multiple ROMs by serving different tracking channels at different time slots, achieving multi-functionality without requiring multiple physical memory devices.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Area of stationary object

If a shared read-only memory (ROM) is used for multiple tracking channels, then silicon area and power consumption are reduced, but access latency may increase

Engineering Contradiction:

Improvesilicon areaVSAvoidmemory access latency

Core Design Contradiction:

Area of stationary objectVSLoss of time

Solution Approach 1:

The patent implements time-multiplexed access to the shared ROM where different tracking channels are served in periodic time slots. The arbitration mechanism allocates memory access rights in a periodic fashion, ensuring that each tracking channel receives timely access to the required Legendre sequences while maintaining efficient utilization of the shared resource.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The arbitration mechanism in the patent performs preliminary allocation of memory access rights before actual data retrieval. By pre-establishing access priorities and time slots for different tracking channels, the system minimizes waiting time and ensures that no channel experiences excessive latency when accessing the shared ROM.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12554022B2Shared read-only memory architecture for pseudo-random code generation in a satellite-based navigation system architecture

Publication Date: 2026.02.17 STMICROELECTRONICS INT NV

AI summary

An apparatus, method, and portable navigation device for determining a PRN code to correlate with a ranging code on a satellite-based navigation system receiver are provided. An example satellite-based navigation system receiver may include a plurality of tracking channels, wherein each tracking channel of the plurality of tracking channels is configured to generate a pseudo-random code based at least in part on a first code value from a first position in a code sequence and a second code value from a second position in the code sequence. The example satellite-based navigation system receiver may further comprise a read-only memory configured to store the code sequence. A second plurality of the plurality of tracking channels may be configured to receive the first code value and the second code value from the read-only memory.