Method, device and system of multi-carrier constant envelope GNSS waveforms compatible with existing user equipment
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Solution Overview
Problem
Existing multi-carrier constant envelope modulation techniques for GNSS are not compatible with existing user equipment, requiring redesign of demodulators, which is costly and inefficient.
Innovation Solution
A method to generate multi-carrier constant envelope waveforms by combining GNSS channels using subcarriers and adding inter-modulation terms, ensuring compatibility with existing user equipment by maintaining a constant envelope property.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing multi-carrier constant envelope modulation techniques are used, then constant envelope property is achieved, but user equipment compatibility deteriorates requiring demodulator redesign
Solution Approach 1:
The patent applies parameter changes by carefully selecting modulation indices and carrier frequencies to ensure the generated waveforms maintain constant envelope property while being compatible with existing user equipment demodulators. The modulation index is specifically chosen to satisfy constant envelope requirements, and the carrier frequencies are configured to work with existing receiver hardware.
Solution Approach 2:
Instead of designing new demodulators to support new modulation schemes, the patent inverts the approach by designing modulation waveforms that can be processed by existing demodulators. The waveform generation is adjusted to be compatible with conventional receiver architecture, effectively solving the compatibility problem by adapting the transmitter side rather than the receiver side.
2Device complexity
If separate transmitters are used for different GNSS bands, then system complexity is reduced, but coherency between channels deteriorates
Solution Approach 1:
The patent merges multiple GNSS band transmitters into a single integrated transmitter that generates multi-carrier waveforms for different bands (L1, L2, L5) simultaneously. This consolidation maintains coherency by ensuring all channels share the same timing reference and signal generation process, while reducing the number of separate transmitters and RF chains required in the system.
3Stability of the object's composition
If wideband multi-carrier modulation is implemented, then coherency among channels is improved, but device complexity increases requiring waveform generation algorithm updates
Solution Approach 1:
The patent segments the wideband multi-carrier modulation into discrete, manageable components by assigning specific subcarriers to different GNSS bands (L1, L2, L5). Each band is handled as a separate subcarrier group within the overall multi-carrier framework, which simplifies the waveform generation process while maintaining coherency across all bands through a unified modulation architecture.
Data Source
AI summary
A global navigation satellite system (GNSS) is disclosed comprising a transmitter. The transmitter is configured to: receive a plurality of frequencies; determine a minimum frequency from the plurality of frequencies; determine a maximum frequency from the plurality of frequencies; determine a carrier from the minimum frequency and the maximum frequency; determine a set of subcarriers from the carrier and the plurality of frequencies; identify optimal radius of desired phase points to select optimal subcarriers from the set of subcarriers; determine inter-modulation terms with a minimal energy based on the optimal subcarriers; and generate multi-carrier constant envelope waveforms based on the inter-modulation terms.