GNSS Signal Chain With Diplexer Splitting and Low-Loss Filtering

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Solution Overview

Problem

Current GNSS receivers face challenges in efficiently processing and distributing navigation satellite signals on different carrier frequencies with minimal insertion loss, interband aliasing, and group delay, while maintaining a compact design.

Innovation Solution

A signal processing chain comprising a diplexer and Wilkinson divider, coupled with band-pass and low-pass filters, splits and distributes signals from an antenna array to multiple GNSS receivers, effectively filtering out-of-band interference and reducing interband aliasing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a signal processing chain processes navigation satellite signals on different carrier frequencies, then multi-frequency reception capability is improved, but insertion loss and group delay increase

Engineering Contradiction:

Improvemulti-frequency reception capabilityVSAvoidinsertion loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The signal processing chain is segmented into distinct frequency paths using diplexers and Wilkinson dividers, separating different carrier frequencies (L1, L2, L5) into independent processing channels. This segmentation allows each frequency to be processed with optimized components, minimizing overall insertion loss while maintaining multi-frequency capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Wilkinson dividers act as intermediary components between the diplexer and individual GNSS receivers, providing impedance matching and isolation. These intermediaries reduce signal reflections and minimize insertion loss by ensuring proper power transfer across frequency bands.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a signal processing chain processes navigation satellite signals on different carrier frequencies, then multi-frequency reception capability is improved, but interband aliasing increases

Engineering Contradiction:

Improvemulti-frequency reception capabilityVSAvoidinterband aliasing

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

Band-pass filters are strategically placed in each frequency path to extract and isolate specific carrier frequency bands (L1, L2, L5) from the composite signal. This extraction prevents out-of-band signals from interfering with the reception of targeted frequencies, eliminating interband aliasing while maintaining multi-frequency operation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Each frequency path is equipped with locally optimized band-pass filters tuned to specific carrier frequencies. This local quality approach ensures that each processing channel has the appropriate filtering characteristics for its designated frequency band, preventing aliasing without compromising other frequency receptions.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If a signal processing chain distributes signals to multiple GNSS receivers, then reception coverage is improved, but device complexity increases

Engineering Contradiction:

Improvereception coverageVSAvoidsignal distribution complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Multiple frequency paths are merged at the diplexer output, allowing a single antenna array to serve multiple GNSS receivers simultaneously. This merging approach consolidates the signal distribution architecture, reducing the number of separate signal paths needed while maintaining comprehensive reception coverage across multiple frequencies and receivers.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The signal processing chain is designed with universal components like Wilkinson dividers and diplexers that can handle multiple frequency bands and serve multiple receivers. This multi-functionality allows the same hardware architecture to support various GNSS constellations and frequencies, reducing overall system complexity while expanding reception coverage.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Measurement precision

If band-pass filters with narrow passband widths are used, then frequency selectivity is improved, but signal loss increases

Engineering Contradiction:

Improvefrequency selectivityVSAvoidsignal loss

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The passband widths of the band-pass filters are optimized to match the specific bandwidth requirements of each GNSS carrier frequency. By adjusting the filter parameters (center frequency and bandwidth) to precisely match the signal characteristics, the system achieves high frequency selectivity while minimizing signal attenuation within the passband.

Inventive Principle:

Principle #35Parameter changes

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

The solution achieves low insertion loss and group delay, enabling precise position determination with reduced interband aliasing, suitable for high-precision GNSS receivers, particularly in vehicle navigation systems.

Implementation Method 1

a first signal splitting with a diplexer for splitting signals to a first main path and a second main path... the diplexer is configured in such a way that at least two different frequency channels for the first GNSS receiver and the second GNSS receiver are transmitted to the first main path

Methodology Applied

Scientific EffectFrequency selective signal splitting: Filter (electronic)

Implementation Method 2

a second signal splitting with a Wilkinson divider for splitting signals from the first main path to a first subpath and a second subpath

Methodology Applied

Scientific EffectSignal power division: Filter (electronic)

Implementation Method 3

a respective band-pass filter is connected in the first main path and in the second main path, the passband widths of which are set taking into account at least one GNSS receiver connected downstream of this band-pass filter

Methodology Applied

Scientific EffectFrequency filtering: Filter (electronic)

Implementation Method 4

a respective low-pass filter capable of suppressing high-frequency interference in a signal received by the antenna array is further connected in the first main path and in the second main path

Methodology Applied

Scientific EffectHigh-frequency interference suppression: Filter (electronic)

Data Source

PatentUS12523779B2Signal processing chain for a GNSS receiver for processing and distributing signals received with an antenna array to GNSS receivers

Publication Date: 2026.01.13 ROBERT BOSCH GMBH

AI summary

A signal processing chain includes a common input for signals received with an antenna array, a diplexer splitting signals to a first path and a second path and a Wilkinson divider splitting signals from the first path to a two subpaths. One GNSS receiver is connected to the first subpath, a second GNSS receiver is connected to the second subpath and a third GNSS receiver is connected to the second path. The diplexer is configured to transmit two different frequency channels for the first GNSS receiver and the second GNSS to the first path. Respective band-pass filters are connected in the first and second path, the passband widths of which are set taking into account at least one GNSS receiver connected downstream of this band-pass filter. Respective low-pass filters suppressing high-frequency interference in a signal received by the antenna array is connected in the first and second path.