Programmable Satellite Waveforms for Interference-Resistant PNT
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current satellite communication systems, including LEO, MEO, and GEO systems, face interference issues due to shared uplink and downlink frequencies, and Global Navigation Satellite Systems (GNSS) suffer from narrow bandwidths, low broadcast angles, and vulnerability to jamming and spoofing, limiting location resolution and requiring extensive ground station updates.
Innovation Solution
A satellite communication system using reversed frequency bands for satellite-to-earth and earth-to-satellite communications, employing higher frequencies (25.5-27.0 GHz and 37.5-42.5 GHz) for improved interference avoidance, increased ranging accuracy, and enhanced signal security through direct spread or frequency hopped signals with selectable encryption and spreading factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If LEO, MEO, and GEO systems operate in co-channel diplex configuration with shared uplink and downlink frequencies, then spectrum utilization is improved, but interference between satellite transmissions and receivers increases
Solution Approach 1:
The patent applies frequency inversion by having LEO/MEO systems use the downlink frequency (20-30 GHz) for uplink communications and the uplink frequency (10-20 GHz) for downlink communications, opposite to conventional GEO systems. This inversion allows co-channel operation without interference because LEO/MEO uplink transmissions occur on frequencies where GEO satellites do not receive, and LEO/MEO downlink transmissions occur on frequencies where GEO satellites do not transmit.
2Adaptability or versatility
If GNSS systems use narrow bandwidths (approximately 10 MHz) and low broadcast angles, then compatibility with broad receiver sets is improved, but location resolution and anti-spoofing capability deteriorate
Solution Approach 1:
The patent changes key signal parameters including bandwidth (using wider bandwidths than traditional 10 MHz), broadcast angle (using higher elevation angles), and waveform characteristics (using spread spectrum and frequency hopping). These parameter changes improve location resolution and anti-spoofing capability while maintaining receiver compatibility through careful design of the signal structure and modulation schemes.
3Device complexity
If GNSS systems use static waveform parameters and low broadcast angles, then signal simplicity is improved, but vulnerability to jamming and spoofing increases
Solution Approach 1:
The patent introduces dynamic characteristics to the GNSS signal through spread spectrum techniques where the signal frequency and phase change rapidly according to a pseudorandom code, and frequency hopping where the carrier frequency changes over time. These dynamic parameters make the signal resistant to jamming and spoofing while maintaining compatibility with receivers that can track these changes.
4Measurement precision
If GNSS satellites rely on regular updates from ground stations for ionospheric calibration and atmospheric scintillation effects, then positioning accuracy is improved, but system complexity and cost increase
Solution Approach 1:
The patent enables satellites to self-correct for ionospheric and atmospheric effects by carrying onboard calibration instruments and using inter-satellite ranging measurements. Satellites autonomously determine and compensate for propagation delays without requiring frequent ground station updates, reducing ground infrastructure complexity while maintaining positioning accuracy.
Data Source
AI summary
A satellite system includes a processor. The processor is configured to determine a waveform and a set of data characteristics for transmitting position and time information using a transmitter of a satellite of the satellite system, wherein the waveform is selectable using a programmable setting; and transmit the position and time information.