Phased Antenna Array Beam Alignment via Pilot Signal Phase Correction
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Solution Overview
Problem
Existing methods for co-phasing signals from a plurality of dish antennas are inefficient due to unknown cable lengths and differing phase responses, leading to prolonged phase adjustment times and potential beam misalignment, especially when communicating with moving targets.
Innovation Solution
A transceiver system that computes and transmits time delay and phase estimates for pilot signals to adjust the timing and phase of information modulated signals across a network of antennas, allowing them to form a narrow-beam phased antenna array by shifting and rotating signals accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If exhaustive phase adjustment methods are used to achieve proper co-phasing of antenna signals, then beam alignment accuracy is improved, but the time required for phase adjustment becomes unacceptably long
Solution Approach 1:
The system performs preliminary phase measurement using pilot signals transmitted from each antenna to a reference receiver. These measurements are stored and used to pre-determine phase correction values, eliminating the need for exhaustive real-time phase adjustment. The phase correction data is computed in advance and applied when forming beams, significantly reducing the time required for beam alignment while maintaining accuracy.
2Speed
If the antenna array is spread over large distances to achieve narrow beamwidth, then beam directionality is improved, but the difficulty of estimating relative phases increases due to unknown cable lengths and differing phase responses
Solution Approach 1:
A reference receiver is introduced as an intermediary device that receives pilot signals from each antenna and provides a common reference point for phase measurement. This reference receiver enables accurate phase comparison across all antennas by serving as a centralized measurement point, solving the problem of phase estimation difficulty that arises when antennas are spread over large distances with unknown cable lengths and varying phase responses.
Solution Approach 2:
The system uses feedback from the reference receiver to measure and determine the phase of signals from each antenna. These measured phase values are used to compute phase correction data, which is then applied to the antenna signals. This closed-loop feedback mechanism enables accurate phase estimation even over large distances by continuously referencing measurements back to the common reference point.
3Measurement precision
If traditional transmit chain phase correction methods are used, then phase alignment may be achieved, but the method is wholly inapplicable when cable lengths differ between transmit and receive chains
Solution Approach 1:
Instead of attempting to correct phase in the transmit chain as in traditional methods, the system inverts the approach by measuring phase in the receive chain using pilot signals transmitted from each antenna to a reference receiver. The phase correction data is then applied in reverse, adjusting the transmit signals based on receive chain measurements. This inversion makes the method applicable regardless of differences between transmit and receive cable lengths, as it directly measures the actual phase conditions in the receive path.
Data Source
AI summary
Method and apparatus for creating a pencil beam using a plurality of small diameter dish antennas. A plurality of small diameter dish antennas are spatially arranged and driven by varying electronic signals in such a way that the plurality of small diameter dish antennas co-operatively produce a pencil beam in the direction of a distant object.