GNSS Receiver Signal Acquisition via Cyclic Buffer and Coherent Accumulation
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Solution Overview
Problem
Global navigation satellite system (GNSS) receivers face significant challenges in efficiently detecting satellite signals due to the large memory and power consumption required for signal acquisition and tracking, especially as the number of Doppler/GNSS satellite combinations increases.
Innovation Solution
The implementation of a GNSS receiver configuration that includes a buffer, Doppler derotation block, accumulator block, register array, and correlator engine, which performs cyclic loading of sample sets, coherent accumulation, and scheduling of searches based on a pre-determined coherent accumulation period to optimize processing load and reduce memory and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of Doppler/GNSS satellite combinations increases to improve signal detection capability, then the reliability of satellite signal detection is improved, but the memory requirement and power consumption increase significantly
Solution Approach 1:
The patent divides the signal processing into separate functional blocks: a buffer for storing sample sets, a Doppler derotation block for frequency correction, an accumulator block for coherent integration, and a correlator engine for code correlation. This segmentation allows each block to handle specific tasks efficiently, reducing the overall memory footprint while maintaining detection capability across multiple Doppler combinations.
Solution Approach 2:
The buffer is pre-configured to store a predetermined number of sample sets (e.g., 20 samples) before processing begins. This preliminary storage eliminates the need for dynamic memory allocation during signal acquisition, reducing peak memory requirements while enabling comprehensive search across all Doppler frequencies and satellite combinations.
2Reliability
If the number of Doppler/GNSS satellite combinations increases to improve signal detection capability, then the reliability of satellite signal detection is improved, but the power consumption increases significantly
Solution Approach 1:
By segmenting the processing into distinct blocks (buffer, Doppler derotation, accumulation, correlation), the system can power down inactive blocks or operate them at reduced capacity when not needed, significantly reducing overall power consumption while maintaining the ability to process multiple Doppler combinations when required.
Solution Approach 2:
The system performs coherent accumulation over predetermined periods (e.g., 1ms, 5ms, 11ms, 19ms) and processes samples in cyclic batches. This periodic operation allows the receiver to enter low-power states between processing intervals while still maintaining detection capability across all Doppler frequencies through the pre-configured buffer.
3Measurement precision
If coherent accumulation is performed for longer periods to improve signal detection sensitivity, then the measurement precision is improved, but the processing load on the correlator engine increases
Solution Approach 1:
The correlator engine is separated from the accumulation function, with the accumulator block handling the computationally intensive coherent integration over extended periods. This segmentation allows the correlator to focus solely on code correlation while the accumulator manages the time-consuming accumulation, effectively distributing the processing load and reducing the correlator's burden.
Solution Approach 2:
The accumulator block acts as an intermediary between the Doppler derotation block and the correlator engine. It receives derotated samples, performs coherent accumulation over the desired period, and outputs accumulated results to the correlator. This intermediary handles the computational complexity of long-period accumulation, allowing the correlator to operate with reduced processing load.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables efficient detection of GNSS satellite signals with reduced area and power consumption, allowing for parallel processing of multiple searches and optimized processing load on the correlator engine, thereby improving the overall performance of the GNSS receiver.
Implementation Method 1
The Doppler derotation block is configured to receive a sample set from among the sample sets loaded in the buffer and perform a Doppler derotation based on one or more Doppler frequencies on the sample set
Data Source
AI summary
A GNSS receiver configured to detect a presence of at least one GNSS satellite signal in a received signal is provided. The GNSS receiver includes a buffer loaded with sample sets corresponding to the received signal and a Doppler derotation block configured to perform a Doppler derotation corresponding to at least one Doppler frequency on a sample set received from the buffer. The GNSS receiver further includes an accumulator block configured to perform a coherent accumulation of a plurality of sample sets upon or subsequent to the Doppler derotation corresponding to a Doppler frequency, and, a first memory configured to store the results of the coherent accumulation. A register array is configured to be loaded with the results stored in the first memory and a correlator engine is configured to generate correlation results by correlating the results in the register array with a plurality of code phases of GNSS satellites.