Narrowband RSSI Circuit for Satellite Interference Rejection
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Solution Overview
Problem
Conventional systems for pointing and tracking earth-station antennas face challenges with adjacent satellite interference, especially with wide beamwidth antennas, and require costly, large, and heavy narrow-beam antennas, which are impractical for on-the-move systems and vulnerable to clock drift and Doppler frequency shifts.
Innovation Solution
A narrow-band Received Signal Strength Indicator (NbRSSI) circuit that tracks the actual communication signal, using a software-controlled Local Oscillator with high frequency stability, adjustable filters, and GPS synchronization to minimize interference and maintain accurate pointing, suitable for wide beamwidth antennas and various RF bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If narrow beamwidth antennas are used to reduce adjacent satellite interference, then interference rejection is improved, but antenna size, weight, and complexity increase
Solution Approach 1:
The patent replaces the mechanical solution of using narrow beamwidth antennas with an electronic signal processing solution. A narrowband RSSI circuit selectively measures signal strength within a specific frequency bandwidth, allowing wide beamwidth antennas to effectively reject adjacent satellite interference through frequency selectivity rather than spatial selectivity. This substitution of electronic filtering for mechanical antenna design resolves the contradiction between interference rejection and system complexity.
Solution Approach 2:
The patent changes the parameter of signal measurement from broad-spectrum power detection to narrowband frequency-selective detection. By measuring RSSI within a specific frequency bandwidth centered on the satellite signal frequency, the system achieves interference rejection equivalent to narrow beamwidth antennas while using simpler wide beamwidth antennas. This parameter change in the detection method resolves the contradiction.
2Object-affected harmful factors
If narrow beamwidth antennas are used to reduce adjacent satellite interference, then interference rejection is improved, but cost increases
Solution Approach 1:
The patent substitutes expensive narrow beamwidth antennas with a cost-effective combination of wide beamwidth antennas and narrowband RSSI measurement circuitry. The electronic frequency filtering approach is significantly less costly than manufacturing and deploying precision narrow beamwidth antennas, especially for satellite tracking applications. This substitution resolves the contradiction between interference rejection and manufacturing cost.
3Ease of operation
If wide beamwidth antennas are used for on-the-move systems, then mobility and ease of operation are improved, but adjacent satellite interference increases
Solution Approach 1:
The patent changes the measurement parameter from total received power (broad-spectrum) to frequency-selective power within a narrow bandwidth. This allows wide beamwidth antennas used in mobile systems to distinguish the desired satellite signal from adjacent satellite interference through frequency discrimination, maintaining mobility benefits while achieving interference rejection.
Solution Approach 2:
The patent replaces the mechanical/spatial filtering function of narrow beamwidth antennas with electronic frequency filtering in the signal measurement circuit. This substitution enables mobile systems using wide beamwidth antennas to achieve interference rejection that would otherwise require complex mechanical antenna systems, resolving the contradiction between mobility and interference rejection.
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 NbRSSI circuit enables efficient and accurate antenna pointing and tracking, reducing interference from adjacent satellites, and is cost-effective, low-power, and suitable for embedded systems, improving Signal to Noise Ratio and reducing setup time.
Implementation Method 1
vulnerable to clock drift and Doppler frequency shift
Data Source
Figure 1~3
Figure 2
Figure 4~5
AI summary
A device and method for tracking a signal of interest from a signal transmitting device, in the presence of cross-polarization or adjacent emitter interference, is provided. An antenna, which may have a beamwidth greater than an angular spacing of geo-stationary transmitting device, is used to receive the signal of interest from a transmitting device. The received signal of interest is analyzed to determine a frequency characteristic of the received signal of interest, and a filter of a plurality of filters (36a-36n) is selected based on the determined bandwidth of the signal of interest. The selected filter is applied to the received signal of interest.