Generalized BOC Signal Acquisition via Side Band Product Detection
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Solution Overview
Problem
The existing signal acquisition methods for Generalized Binary Offset Carrier (BOC) modulated signals face significant squaring losses, particularly in the acquisition of signals like BOC(15,2.5), which reduces code binwidth and increases the number of correlators required, leading to inefficiencies in the acquisition process.
Innovation Solution
A method for signal acquisition of Generalized BOC modulated signals, involving coherent integration over a time duration independent of symbol or data duration, and using a Side Band Product (SBP) detector that multiplies complex correlation outputs from left and right side lobes, reducing squaring losses and improving acquisition performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional acquisition methods are used for Generalized BOC modulated signals, then the Auto-Correlation Function contains multiple peaks, but this forces reduction of code binwidth and increases the number of correlators required
Solution Approach 1:
The patent segments the BOC signal into left and right side lobes separated by the sub-carrier frequency. By processing each side lobe independently and combining their correlation outputs, the method effectively narrows the Auto-Correlation Function main peak without requiring reduction of code binwidth, thus avoiding the need for increased number of correlators
Solution Approach 2:
The patent introduces an intermediary processing step where the correlation outputs from left and right side lobes are combined through multiplication rather than direct addition. This intermediary combination method enhances the main peak of the Auto-Correlation Function while maintaining adequate code binwidth, resolving the contradiction between measurement precision and device complexity
2Measurement precision
If coherent integration time is extended to improve detection sensitivity, then detection sensitivity improves, but symbol or data duration constraints limit the integration time
Solution Approach 1:
The patent segments the signal processing into separate left and right side lobe correlations, each processed independently. This segmentation allows the coherent integration time to extend beyond symbol or data duration because the side lobe structures maintain their correlation properties over longer periods, enabling extended integration for improved detection sensitivity
Solution Approach 2:
The patent enables continuous useful action by allowing coherent integration to proceed without being interrupted by symbol or data transitions. The side lobe correlation method maintains signal structure integrity over extended periods, permitting continuous integration that accumulates signal energy and improves detection sensitivity beyond traditional symbol-duration limits
3Reliability
If squaring losses are reduced to improve acquisition performance, then acquisition performance improves, but conventional methods incur significant squaring losses
Solution Approach 1:
The patent introduces an intermediary multiplication operation between the left and right side lobe correlation outputs. This intermediary step combines the side lobe correlations in a manner that preserves signal energy and avoids the squaring losses inherent in conventional methods, thereby improving acquisition performance while minimizing energy loss
Solution Approach 2:
The patent changes the combination parameter from conventional addition or squaring to multiplication of complex correlation outputs. This parameter change in the combination operation reduces squaring losses by maintaining the phase and amplitude information from both side lobes, thereby improving acquisition reliability while reducing energy loss
Data Source
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AI summary
The present invention provides a method for signal acquisition of a Generalized Binary Offset Carrier, G-BOC, modulated signal comprising K elementary BOC(Mk,Nk)-modulated signals. The method comprises retrieving for each of the K elementary BOC(Mk,Nk)-modulated signals a lower sideband signal and an upper sideband signal by respectively up-converting and down-converting the respective elementary BOC(Mk,Nk)-modulated signal under use of a sub-carrier frequency fsc,k corresponding to the respective elementary BOC(Mk,Nk)-modulated signal and by respectively lowpass filtering the up-converted and down-converted respective elementary BOC(Mk,Nk)-modulated signal. The method comprises respectively correlating a replica modulated with the primitive pulse shape involved in the generation of the BOC(Mk,Nk)-modulated signal such as binary phase shift keying, BPSK, pulse shape with the retrieved lower and upper sideband signals. The replica has a chip rate, for example fc,k=Nk×f0, and a spreading sequence according to the respective elementary BOC(Mk,Nk)-modulated signal. The chip rate can be expressed as chips per second, abbreviated Cps. The spreading sequence can be a binary noise like sequence. The replica is generated on the basis of a code delay hypothesis and a Doppler frequency hypothesis. The method comprises multiplying the respective correlation results by complex or complex conjugate multiplication. The method further comprises generating a first detector output by adding the corresponding K complex or K complex conjugate multiplications and/or generating a second detector output by adding NNC successive detector outputs, each being the sum of the K complex or K complex conjugate multiplications. The method comprises acquiring the G-BOC-modulated signal corresponding to the code delay hypothesis and Doppler frequency hypothesis, when the first and/or second detector output being compared to a detection threshold indicates detection. Further, the present invention provides a device for signal acquisition of a Generalized Binary Offset Carrier, G-BOC, modulated signal comprising K elementary BOC(Mk,Nk)-modulated signals.