SAR System Chirp Modulation for Satellite Weight Reduction

Solution Overview

Problem

Low-Earth orbit satellites require separate antennas and transceivers for SAR operations and data transmission, leading to increased weight and size due to the need for dual systems.

Innovation Solution

A synthetic aperture radar (SAR) system that uses chirp pulses and phase shift keying to modulate data transmission, allowing for simultaneous SAR operations and data transmission using a single transceiver and antenna.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate antennas and transceivers are installed for SAR and data transmission, then frequency overlap between SAR signals and data transmission signals is prevented, but satellite weight and size increase

Engineering Contradiction:

Improvefrequency separationVSAvoidsatellite weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent combines SAR imaging function and data transmission function into a single transceiver and antenna system. The modulator modulates SAR chirp signals with data signals, allowing both functions to share the same hardware components, thereby reducing satellite weight and component count while preventing frequency overlap through signal processing rather than physical separation

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The transceiver is designed to perform multiple functions: SAR imaging and data transmission. By making the transceiver universal and capable of handling both SAR chirp signals and data signals through modulation, the system eliminates the need for separate dedicated transceivers for each function, reducing overall system weight and complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If separate antennas and transceivers are installed for SAR and data transmission, then frequency overlap between SAR signals and data transmission signals is prevented, but satellite size increases

Engineering Contradiction:

Improvefrequency separationVSAvoidsatellite volume

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent combines SAR imaging function and data transmission function into a single transceiver and antenna system. The modulator modulates SAR chirp signals with data signals, allowing both functions to share the same hardware components, thereby reducing satellite weight and component count while preventing frequency overlap through signal processing rather than physical separation

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The transceiver is designed to perform multiple functions: SAR imaging and data transmission. By making the transceiver universal and capable of handling both SAR chirp signals and data signals through modulation, the system eliminates the need for separate dedicated transceivers for each function, reducing overall system weight and complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Weight of moving object

If a single transceiver is used for both SAR operations and data transmission, then satellite weight and size are reduced, but frequency overlap between SAR signals and data transmission signals occurs

Engineering Contradiction:

Improvesatellite weightVSAvoidfrequency separation

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The patent uses modulation to change the frequency parameters of the SAR chirp signals by embedding data signals within them. This frequency modulation allows the single transceiver to transmit both SAR imaging data and communication data on the same carrier frequency without interference, as the data is encoded in the frequency variations of the chirp signal

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The modulator acts as an intermediary component that combines the SAR chirp signal and the data signal before transmission. It embeds the data signal into the SAR chirp signal through modulation, allowing the single transceiver to handle both functions simultaneously while preventing frequency overlap through controlled signal mixing

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enables efficient data transmission and reception during SAR operations, reducing the need for separate systems and minimizing satellite size and weight, while maintaining effective SAR imaging capabilities.

Implementation Method 1

a chirp pulse modulation unit configured to generate modulated chirp pulses by modulating the chirp pulses through phase shift keying according to at least one bit value of the transmission data

Methodology Applied

Scientific EffectPhase shift keying: Phase Modulation

Data Source

PatentUS20250172692A1Synthetic aperture radar system

Publication Date: 2025.05.29 KOREA AEROSPACE RES INST

AI summary

A synthetic aperture radar (SAR) system includes a chirp pulse generation unit configured to generate chirp pulses with a frequency increasing with time, a data storage unit storing transmission data, a chirp pulse modulation unit configured to generate modulated chirp pulses by modulating the chirp pulses through phase shift keying according to at least one bit value of the transmission data, and a transceiver unit configured to convert the modulated chirp pulses into a radio signal and transmit the radio signal.