Time Weighted BPSK Code Combining for GPS III
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Solution Overview
Problem
The Global Positioning System (GPS) III faces challenges in combining additional binary phase shift key (BPSK) codes with existing GPS IIF codes while maintaining constant power, as existing solutions like Interlace combining require a uniform random number generator, which may not ensure backward compatibility with existing GPS receivers.
Innovation Solution
A method for time-weighted combining of BPSK code sequences using a majority vote (MV) technique, where samples are selected based on their respective gains, forming a time multiplexed composite BPSK code sequence without the need for a uniform random number generator, ensuring compatibility and constant power transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Interlace combining technique is used to combine additional BPSK codes, then the codes can be combined with existing GPS IIF codes, but the requirement for a uniform random number generator compromises backward compatibility with existing GPS receivers
Solution Approach 1:
The patent extracts and removes the dependency on uniform random number generators from the code combining process. By eliminating this component, the system achieves backward compatibility with existing GPS receivers while maintaining the ability to combine multiple BPSK codes through deterministic time-weighted majority vote combining.
Solution Approach 2:
The patent creates a simplified version of the Interlace combining technique that copies its core functionality (time-multiplexed code combining) while replacing the random number generator component with a deterministic time-weighted selection mechanism, thus preserving compatibility.
2Ease of operation
If a uniform random number generator is used in Interlace combining, then code sequences can be randomly selected for combination, but the authenticity and authenticity period of the random generator affect receiver integration time
Solution Approach 1:
The patent replaces the mechanical/random system (uniform random number generator) with a deterministic time-weighted system. This substitution eliminates the authenticity period requirement and allows receivers to achieve lock faster, reducing integration time while maintaining code combining flexibility through time-proportional selection.
3Quantity of substance
If additional BPSK codes are combined with existing GPS codes, then more information can be transmitted, but maintaining constant power becomes more difficult
Solution Approach 1:
The patent changes the selection parameter from random to time-weighted, where the probability of selecting each code sequence is proportional to its weight. This parameter change allows multiple codes to be combined while maintaining constant average power through deterministic time-multiplexing rather than random selection.
Data Source
AI summary
A method for time weighted combining of a plurality of binary phase shift key (BPSK) code sequences that is implemented by providing first, second and third sequences of chips of a BPSK code having a first, second and third code powers, respectively. A majority vote (MV) sequence of chips from the first, second and third sequences of chips is determined and a time multiplexed composite BPSK composite code sequence is formed by selecting a specific number of samples from each of the MV sequence of chips, and the two sequences of chips of the first, second and third sequences of chips that have the highest code powers, to form samples in a unit duration.