172 results about "Tracking loop" patented technology

The invention provides a GNSS deception jamming detection method and system based on LSTM, and relates to the technical field of global satellite navigation systems. Acquiring a target signal through a receiver in the GNSS tracking loop model; acquiring output information of the tracking loop; selecting four types of basic SQM detection quantities of Ratio, Delta, ELP and PCS as a detection quantity set; generating a characteristic parameter set according to the output information and the detection quantity set; preprocessing the feature parameter set by using a sliding window technology to generate standardized data; and inputting the standardized data into a preset LSTM model to obtain a detection result corresponding to the target signal. The technical effect of effectively identifying the navigation deception is realized.

The invention relates to the technical field of inertial assistance, in particular to a Beidou high-precision space-time reference dynamic compensation system based on inertial assistance, which is characterized in that an inertial measurement unit module is used for measuring original measurement data, and the original measurement data comprises a carrier phase and a Doppler observation value; the processing unit module is used for fusing the inertial measurement unit, executing real-time environment perception and dynamic modeling, classifying an operation environment and predicting error characteristics; performing an adaptive robust fusion filtering algorithm that dynamically adjusts filter parameters and switches a filter model to estimate the position and attitude of the carrier; and in combination with radio wave precision single-point positioning enhancement service, super-tight combination signal tracking and integrity monitoring are realized, an estimated inertial assistance system state is fed back to a tracking loop of the multi-frequency Beidou receiving module, and real-time fault detection is performed on original measurement data.

The invention provides a GNSS deception jamming detection method and system, and relates to the technical field of GNSS. GNSS signals of a plurality of satellites are collected, and self-correlation power information of each channel is obtained through a tracking loop; acquiring lead, instant and lag correlator outputs of each channel from the self-correlation power information of each channel, and constructing a tracking loop self-correlation power detection quantity of a single satellite; performing moving average filtering processing on the tracking loop autocorrelation detection quantity to generate a TLAP-MA detection quantity; combining the TLAP-MA detection quantities of the plurality of satellites to construct a multi-satellite combined matrix, and performing dynamic classification judgment based on a preset judgment threshold; and according to the dynamic classification judgment result, multi-path interference and spoofing attack are distinguished, and a detection result is output. The technical effect of effectively detecting and distinguishing GNSS deception jamming and multipath jamming is achieved.

A self-adaptive high-dynamic spread spectrum tracking receiver relates to the technical field of satellite communication and comprises an AGC loop, an A / D converter, a PN code capturing and tracking loop, a single carrier loop, a despreading device, a phase discriminator, a phase shift signal generator and a low-pass processor. The method comprises the following steps of: converting a signal into a digital signal, subsequently generating an output tracking signal through a PN code capturing and tracking loop, processing through a single carrier loop to obtain a captured tracking signal and an amplitude excitation signal, and finally carrying out de-spreading and phase discrimination to generate an azimuth error voltage signal and a pitching error voltage signal; the receiver can stably receive and process spread spectrum signals sent by a high-speed target.

One general aspect includes a method of wireless communication performed by a user equipment (UE). The method of wireless communication also includes receiving a configuration defining uneven reference signals in a time domain, including defining the uneven reference signals to be received before a paging early indication (PEI) and between the PEI and a paging occasion (PO); exiting a sleeping mode to receive the uneven reference signals before the PEI and between the PEI and the PO, performing a tracking loop adjustment based on the uneven reference signals, decoding a paging message after the tracking loop adjustment, and returning to the sleeping mode. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.

The invention discloses an airborne low-detectability photoelectric long-distance stable tracking and aiming method based on a time-sensitive opposite target, and belongs to the technical field of airborne photoelectric detection and target tracking. The method comprises the following steps: step 1, target detection and miss distance calculation: in a level flight section of an airplane, imaging a target in a field of view, carrying out target detection by adopting an optical flow method, and detecting a moving target by analyzing a motion vector of pixel points in an image sequence; and resolving the deviation amount of the target image relative to the visual axis in real time, namely the target pixel miss distance. 2, designing a stable tracking loop: designing a two-layer control structure for the stable tracking loop, stably inhibiting high-frequency disturbance by a gyroscope of an inner loop, performing tracking correction on low-frequency deviation by an outer loop based on pixel miss distance, and finally realizing high-precision tracking. On the basis of real-time pixel miss distance feedback, a two-layer control structure is designed, the miss distance fed back by an outer ring tracking loop is converted into an inner ring control instruction, and the tracking precision and stability are improved.

The invention discloses a GNSS (Global Navigation Satellite System) signal spoofing detection method, device and equipment, a storage medium and a program product. The method comprises the following steps: tracking and monitoring a plurality of GNSS satellite signals, calling a tracking loop correlator to carry out autocorrelation operation to obtain the autocorrelation power of each satellite signal, constructing the AP detection quantity of each satellite signal based on the autocorrelation power, verifying the Gaussian property of the AP detection quantity, and carrying out moving average filtering processing on the AP detection quantity conforming to Gaussian distribution to obtain the AP detection quantity of each satellite signal. The method comprises the following steps: acquiring Gaussian distribution characteristic information of a GNSS satellite signal, constructing an AP-MA detection quantity, determining a detection threshold according to the Gaussian distribution characteristic information, detecting the AP-MA detection quantity based on the detection threshold, and judging whether the GNSS satellite signal has deception jamming or not; the AP detection quantity is constructed based on the self-correlation power to carry out signal spoofing detection, so that the detection range and the detection precision are effectively improved, and the timeliness and the stability of spoofing detection are ensured under the condition of not increasing additional equipment and algorithm complexity.

The invention discloses a converter grid following-grid construction control mode smooth switching method suitable for wide-range source-grid state change. The method comprises the following steps: constructing a phase-locked loop control loop, a power outer loop control loop and a current inner loop control loop of a grid following type converter based on constant power control; constructing a voltage control loop, a phase control loop and a voltage and current double-closed-loop control loop of the network construction type converter based on the virtual synchronous generator VSG; calculating real-time output active power P and reactive power Q of the converter; constructing a voltage phase synchronization loop switching control loop and a current instruction tracking loop, and realizing smooth switching of dq-axis current instruction values output by a power outer loop of a following network type and a voltage outer loop of a construction network type; and the output dq-axis current instruction value is transmitted to a current inner loop to generate a final voltage signal, and a PWM wave is output to the converter through a modulation link. According to the method, a voltage phase synchronous switching compensation mechanism is adopted, a voltage amplitude and a phase signal are synchronously corrected in the mode switching process, and smooth change of an inner ring current reference signal is achieved.

The invention relates to a satellite navigation baseband processing device optimized by a coprocessor. A core processing part of the device adopts a realization framework of a main processor and a coprocessor; the coprocessor is used for scheduling hardware acceleration computing resources in real time under exchange control of the main processor, and completing high-real-time processing tasks such as signal capture and tracking loop processing of satellite navigation; an instruction set and an external interface of the coprocessor are subjected to targeted optimization, the bus bit width and the internal storage width of the coprocessor are expanded, and the in-situ width of an ALU and a register of the coprocessor is reserved; performing bus data access and storage by adopting an external port access instruction and an internal memory access instruction which are matched with the expanded bus according to the expansion state; and performing access and storage of single register data by adopting a bus write enable, an access instruction and a storage instruction which are matched with the expanded internal storage width. According to the invention, the function load of the main processor is effectively reduced, and the implementation cost of the baseband processing device is reduced.

The invention relates to the technical field of high-precision anti-interference satellite navigation, and particularly discloses a high-precision anti-interference navigation antenna array attitude autonomous estimation method, which comprises the following steps: designing a multi-antenna carrier tracking loop, and measuring a carrier phase in an interference environment; clock difference and ionosphere and troposphere delay are eliminated by means of carrier phase double difference between array elements. Solving a unique solution of each baseline vector from a carrier phase double-difference equation by utilizing the constraint that the array element spacing does not exceed the carrier half-wavelength; rough estimation of the array attitude is obtained according to the least square solution of the equation set satisfied by each baseline vector; compensating the phase error of each array element by utilizing rough attitude estimation; according to the sequence of inter-array element carrier phase double-difference calculation, multiple baseline vector solution, array plane attitude rough estimation and array element phase error compensation, performing iteration for three times to obtain array plane attitude accurate estimation; an attitude sensor, an INS antenna and a GNSS antenna do not need to be additionally installed, the method does not depend on other navigation sources, calibration is not needed, estimation errors are not accumulated, and the initialization time is short.

The present invention discloses a GNSS spoofing interference detection method based on combined SQM square, which includes the following steps: obtaining the carrier-to-noise ratio, correlator spacing, and coherent integration time of a GNSS receiver, and calculating the coherent integration values of the early path, prompt path, and late path of the tracking loop; calculating three SQM metrics, namely Delta, Ratio, and ELP, according to the coherent integration values; calculating the statistical characteristics of the SQM metrics based on the carrier-to-noise ratio, correlator spacing, and coherent integration time of the receiver; establishing a combined detection quantity; setting a false alarm rate, and determining a decision threshold according to the statistical distribution of the combined detection quantity; setting a time window length, and making a decision according to the decision threshold within the detection time to achieve spoofing interference detection. The method disclosed by the present invention does not need to change the receiver structure, has a wide range of applicable scenarios, can be applied to static and dynamic receivers, and has good detection effects on small-delay spoofing interference and complex offset spoofing interference.

The invention belongs to the technical field of wireless communication, and particularly discloses a high-dynamic stable tracking method for non-spread-spectrum continuous wave signals. The method comprises the following steps: obtaining a digital signal based on ADC sampling, and carrying out digital frequency conversion on all sampling points of a current symbol according to a current estimated frequency result to obtain a digital baseband signal; a digital baseband signal under 4 times of oversampling is obtained through multi-stage downsampling, matched filtering processing is carried out on the digital baseband signal under 4 times of oversampling, and an output result of a preset position in matched filtering output is determined as an optimal sampling point to serve as output of a tracking loop; and performing timing error estimation according to an output result of the matched filtering, adjusting the sampling deviation of the next section of data by using a timing error estimation result, solving a phase discrimination value according to the optimal sampling point, and adjusting the digital frequency conversion of the next section of data by using the phase discrimination value. According to the scheme, the technical problem that the non-spread-spectrum continuous wave signal cannot be continuously and stably tracked in a high-dynamic scene is solved.

The invention discloses a GNSS-R terminal baseband three-ring cooperative tracking method, system and device and a medium, and belongs to the technical field of satellite navigation signal processing, and the method comprises the steps: receiving a digital intermediate frequency BOC modulation satellite navigation signal; establishing a carrier tracking loop, a subcarrier tracking loop and a code tracking loop; performing frequency mixing operation on the digital intermediate frequency BOC modulation satellite navigation signal and a local carrier wave; performing correlation operation on the signal after the frequency mixing operation and a local subcarrier and a local pseudo-random code in sequence; carrying out accumulation processing on a correlation operation result to obtain a correlation accumulation value; respectively calculating error adjustment parameters of the carrier tracking loop, the subcarrier tracking loop and the code tracking loop based on the correlation accumulation values; and when the error adjustment parameters of the carrier tracking ring, the subcarrier tracking ring and the code tracking ring are all within a preset range, outputting navigation data. According to the invention, the problem that a traditional double-ring method cannot fully utilize subcarrier components is solved.

The invention discloses a lunar exploration cubesat measurement and control responder system and a transmitting signal coherent carrier generation method thereof, and the system comprises a frequency mixer, a receiving local oscillator phase-locked loop, an intermediate frequency sampling analog-to-digital converter, a voltage-controlled oscillator, a digital-to-analog converter, a transmitting local oscillator phase-locked loop and a carrier tracking loop. Wherein the frequency mixer generates an intermediate-frequency signal according to radio frequency input and a local oscillation signal, the intermediate-frequency signal is output to the intermediate-frequency sampling analog-to-digital converter after band-pass filtering, and the intermediate-frequency sampling analog-to-digital converter outputs the intermediate-frequency signal to the carrier tracking loop after the intermediate-frequency signal is subjected to down-conversion processing of an X-band radio frequency signal; the carrier tracking loop outputs a digital signal to the digital-to-analog converter to generate an analog voltage for controlling the voltage-controlled oscillator; the voltage-controlled oscillator controls the output frequency through the voltage of the digital-to-analog converter; receiving a reference signal output by the local oscillator phase-locked loop according to the voltage-controlled crystal oscillator, performing phase-locked frequency multiplication processing and generating a local oscillator signal; and the transmitting local oscillator phase-locked loop performs phase-locked frequency multiplication processing on the reference signal. According to the invention, in an analog-digital combination mode, a digital frequency-locked phase-locked loop is used for controlling the output voltage of a DAC to control the frequency of a reference VCXO, so that carrier tracking of a radio frequency-intermediate frequency-digital large loop closed loop is completed; downlink coherent carriers can be directly obtained by PLL (Phase Locked Loop), and the requirement of downlink / uplink forwarding ratio 880 / 749 is strictly met.

The invention provides a deception jamming detection method, electronic equipment, a storage medium and a product. The method comprises the following steps: acquiring in-phase channel outputs and orthogonal channel outputs of a plurality of correlators; constructing a first detection quantity of the correlator according to the in-phase channel output and the orthogonal channel output of the correlator; constructing a second detection quantity of the correlator according to the first detection quantity of the correlator within a period of time; and taking the processed second detection quantity of the correlator as the input of a machine learning network model, and training the machine learning network model to obtain a deception jamming detection model. According to the method, the amplitude output of a plurality of correlators of a receiver tracking loop is utilized, the distortion effect of a deception signal invading the tracking loop on a correlation peak can be fully reflected, and the influence of carrier phase difference of the deception signal and a real signal on an algorithm can be relieved; dynamic changes caused by deception jamming can be captured, and the detection sensitivity and accuracy are improved.

A demodulator comprises a first-stage carrier demodulator and a second-stage carrier demodulator. The first-stage carrier demodulator is configured to remove or compensate for the tracking error in the baseband signal, where the tracking error comprises aggregate, channel tracking error of carrier phase for the same received band, sub-band, (baseband) GNSS satellite channel, or set GNSS channels. The second stage carrier demodulator is configured to remove or strip a carrier signal component without any unwanted image or carrier-related frequency artifacts and to prepare for correlation-based decoding or demodulation of the encoded baseband signal by the correlators. First correlators are configured to determine correlations for code phase tracking loop, where the code phase tracking loop is configured to estimate a corresponding code error component of the tracking error for the code local oscillator for a respective channel. Secondary correlators are configured to determine correlations for a carrier phase tracking loop, where the carrier phase tracking loop configured to estimate a corresponding aggregate feedback error for multiple channels or a set of channels.

The invention relates to the technical field of satellite navigation meteorological remote sensing, and discloses a water vapor ionized layer snow depth integrated detection method and system. The method comprises the steps that direct and reflected signals of a Beidou satellite are received through fusion antenna array differentiation, carrier phase and pseudo-range observation values are obtained through carrier tracking loop synchronous demodulation, the total atmospheric rainfall amount and the total ionosphere electron content are extracted through a troposphere and ionosphere combined calculation algorithm, the snow depth is inverted through reflection path geometric difference, and the snow depth is calculated. And carrying out space-time synchronization constraint processing on the extended Kalman filter to realize multi-parameter integrated detection. The problems of low efficiency, insufficient precision and lack of cooperative processing caused by independent observation of water vapor, ionized layer and accumulated snow parameters in the prior art are solved, and the observation efficiency and the measurement precision of multi-parameter integrated detection are improved.

A clock and data recovery circuit includes a frequency tracking loop and a phase tracking circuit. The frequency tracking loop includes an injection locked oscillator configured to adjust an oscillation frequency to generate an output signal, receive an input data signal, and extract an output clock from the input data signal, where the output signal has a frequency tracking a reference clock frequency. The phase tracking circuit is coupled to the frequency tracking loop and includes a phase interpolator and a finite state machine. The phase interpolator is used for receiving an output clock and adjusting the phase of the output clock according to an input program code to generate a sampling clock for sampling a signal to generate an anti-serialized signal. The finite-state machine is coupled to the phase interpolator and is used for outputting the program code to the phase interpolator according to the anti-serialization signal of the multiplexer so as to adjust the phase of the output clock.

The invention provides a frame header synchronization method based on a CPM constant envelope spread spectrum sequence, and belongs to the technical field of satellite-borne satellite communication. A traditional recursive feedback type structure based on a phase-locked loop (PLL) is optimized, and a matched filter, a resampling module and a delay locked tracking loop (DLL) module are added after frame header pulse detection and frequency offset estimation are completed by utilizing the differential self-correlation characteristic of a synchronous sequence. The single symbol rate timing error estimation result serves as negative feedback and is fed back to the matched filter for resampling operation, the optimal resampling point is continuously adjusted, the symbol synchronization establishment time is greatly shortened, and then frame header synchronization of LINK20 received signals is achieved. The method has the advantages of being easy to implement, low in complexity and high in real-time performance and synchronization precision.

The invention provides a space laser communication optical axis control device and method, a first-stage fine tracking loop uses a photoelectric detector to cooperate with a fast reflector 1, a second-stage fine tracking loop uses a nutation assembly to cooperate with a fast reflector 2, and the tracking zero position of the first-stage fine tracking loop is corrected according to the offset of a second-stage fast reflector. The light beam control system is applied to space laser communication, and through cooperation of the two stages of fine tracking loops, the light beam control system has the advantage of being capable of restraining light beam jitter caused by high frequency and strong vibration and has the advantage of compensating deviation of a communication optical axis and a tracking optical axis in real time.

The invention relates to a satellite navigation signal weak signal tracking loop switching method. The method comprises the following steps: designing a loop filter of a double-frequency phase-locked loop, a loop filter of a double-frequency frequency-locked loop and a loop filter of a pilot component single-frequency frequency-locked loop based on a Kalman filtering algorithm; constructing observed quantity and state quantity of a Kalman filter based on phase discrimination, frequency discrimination and code discrimination results of the B2a signal and the B1I signal; the state quantity output by the loop filter is fed back to a local carrier generator and a composite spreading code generator for error correction; in the filtering process, the adopted loop filter is switched according to the carrier-to-noise ratio, the phase locking detection index and the frequency locking detection index of the two signals, the corresponding loop filter is adaptively selected to complete parameter estimation, loop locking is further carried out, and signal tracking and positioning are achieved.

The present invention discloses a debugging method for a tracking loop of a real-time zoom tracking control system, the method comprising: sampling a plurality of focal length values ​​within the focal length range of a television system of an optoelectronic tracker, obtaining tracking deviation pixels corresponding to each sampled focal length value; determining the correspondence between the focal length, tracking deviation pixels of the television system and the tracking deviation of the tracking loop of the optoelectronic tracker; obtaining the current focal length value of the television system and the current tracking deviation pixels of the tracking loop, determining the current tracking deviation of the tracking loop of the optoelectronic tracker, and compensating the tracking loop based on the current tracking deviation. The present invention can effectively ensure the tracking accuracy of the optoelectronic tracker at short focus, and at the same time ensure the tracking accuracy of the optoelectronic tracker at long focus, that is, ensure the tracking accuracy during the entire process of continuous zooming of the television system.

The invention belongs to the technical field of navigation receivers, and relates to a CP-OFDM signal navigation receiving method and a navigation receiver. The method comprises the following steps: performing down-conversion on a received CP-OFDM signal to obtain an intermediate frequency signal; sending the intermediate frequency signal into an incoherent delay tracking loop, wherein the incoherent delay tracking loop comprises a leading branch, an instant branch and a lagging branch; the leading branch and the lagging branch process the intermediate frequency signal to obtain coherent integral amplitudes respectively; when the two branches process the intermediate frequency signal, local copy signals are generated firstly, and the protection interval of the local copy signals is filled to be zero; calculating according to the amplitude of the coherent integration of the two branches to obtain signal propagation time delay; eliminating noise to obtain a filtered time delay value; and estimating the time delay experienced by the received signal based on the filtered time delay value, and estimating the position information of the receiver. The problem that the cyclic prefix and the adjacent frequency points in the CP-OFDM signal influence the navigation tracking precision is solved.

Methods, systems, and devices for wireless communications are described. In some examples, a user equipment (UE) may receive configuration information that indicates one or more paging occasions and an idle discontinuous reception (I-DRX) mode. The UE may monitor the one or more paging occasions based at least in part on a transition from a sleep state to a monitoring state in accordance with the I-DRX mode. The UE may receive a paging message associated with the one or more paging occasions based at least in part on the one or more paging occasions being monitored. The paging message is addressed to a different UE, and the paging message may include a demodulation reference signal (DMRS), data, or both. A tracking loop may be adjusted based on the DMRS, the data, or both.

The invention provides a high-mobility platform random access method and system for a low-orbit satellite data chain, and the method comprises the steps: taking a satellite ephemeris and platform navigation information as initial guidance, receiving and analyzing a satellite downlink signal, and carrying out the joint estimation to obtain a space-time frequency parameter; based on the estimated timestamp as a time reference of a frequency hopping pattern, driving a local frequency hopping sequence generator, predicting and verifying the current frequency hopping pattern, and performing frequency offset correction according to the estimated Doppler frequency offset; and in response to successful verification of the frequency hopping pattern, constructing a pre-compensated uplink and starting a frequency hopping pattern tracking loop for fine tuning of the time-space-frequency parameter and the frequency hopping pattern phase, so that the user accesses the low-orbit satellite data link at random and enters steady-state communication. The time-space-frequency alignment problem and the time-varying frequency hopping pattern capturing and tracking problem are synchronously solved, and rapid, reliable and anti-interference random access of the high-mobility platform is achieved.

The invention discloses a searching and tracking method for high-real-time flight path updating, and the scheme mainly comprises the steps: (1) initializing a system, and confirming the parameters and thresholds of all modules; (2) receiving trace points and carrying out sidelobe interference suppression; (3) calculating an effective target of a target threat degree selection wave position; (4) carrying out high-precision distance measurement based on a centroid positioning algorithm and distance-Doppler coupling solution and high-precision angle measurement based on a sum-difference amplitude comparison angle measurement algorithm; (5) plot condensation of adjacent wave position detection targets in the same circle; (6) associating trace points of adjacent beam position detection targets in adjacent circles; (7) performing tracking loop construction on the effective target group; and (8) after the tracking loop is successfully constructed, the state is not searched before the target is completely lost, and a new tracking loop is constructed. According to the high-precision and high-updating-rate searching and tracking method, target track information is updated at a high speed after a tracking loop is constructed, and compared with traditional TWS and TAS, target real-time information can be obtained more timely for stable tracking.

The invention discloses an automatic bandwidth adjustment system and a rotary transformer digital converter, and relates to the technical field of rotary transformer digital converters, and the system comprises an angle error calculation module, a tracking loop module and an automatic bandwidth adjustment module. The angle error calculation module is used for outputting a first angle error signal and a second angle error signal to the tracking loop module and the automatic bandwidth adjustment module; the tracking loop module is used for receiving the first angle error signal, performing phase tracking on the sine and cosine signals to obtain a second speed signal and a rotating phase signal, and sending the second speed signal to the automatic bandwidth adjusting module; the automatic bandwidth adjusting module is used for comparing the second angle error signal with a preset angle threshold value to obtain a first comparison signal, comparing the second speed signal with a preset speed threshold value to obtain a second comparison signal, and sending the first comparison signal and the second comparison signal to the tracking loop module. Therefore, different system bandwidth coefficients can be switched.

The invention discloses a navigation deception detection method and device based on multiple correlators and variance filtering, equipment and a storage medium, and relates to the technical field of GNSS detection, and the method comprises the steps: receiving a mixed signal containing a real satellite signal, a deception signal and a noise signal; on the basis of the mixed signal, an output amplitude is obtained through a correlator in a tracking loop, an MCTO first-level detection quantity is constructed, and the MCTO first-level detection quantity obeys Gaussian distribution; performing variance filtering processing on the MCTO primary detection quantity to obtain an MCTO-MV secondary detection quantity; determining a detection threshold based on the detection quantity distribution characteristics, and determining a detection probability based on the detection threshold; and obtaining a navigation deception detection result according to the MCTO-MV secondary detection quantity and the detection probability. According to the method, the induced navigation spoofing attack can be timely and effectively detected, and the safety and reliability of a navigation system are improved.

This invention relates to a method and system for monitoring and enhancing the power of GPS P(Y) signals based on civilian signal tracking. The method employs a carrier tracking loop to stably track civilian satellite navigation signals, generating a local carrier with the same frequency and phase as the GPS satellite navigation digital signal. The GPS satellite navigation digital signal is then orthogonally mixed with the local carrier to output the in-phase branch signal u. I (n) and the orthogonal branch signal u Q (n); the in-phase branch signal u I (n), Orthogonal branch signal u Q (n) Perform low-pass filtering and incoherent integration respectively to obtain the average power P of the baseband signal in the in-phase branch. IB Average power P of baseband signal in orthogonal branch QB The average power P of the baseband signal in the same phase branch IB Average power P of baseband signal in orthogonal branch QB The power enhancement state of the current P(Y) signal is determined by comparing it with the weak-state power threshold of the in-phase branch, the strong-state power threshold of the in-phase branch, the strong-state power threshold of the quadrature branch, and the weak-state power threshold of the quadrature branch.

The application relates to the technical field of fraud detection, and discloses a detection method and system for spoofing attacks / natural electromagnetic interference, which comprises: a first detection quantity based on absolute tracking loop output (ATLO); mobile variance filtering processing (ATLO-MV) is performed on the first detection quantity to construct a second detection quantity; and the detection probability information of the second detection quantity of ATLO-MV of multiple satellites is used to distinguish spoofing attacks, natural electromagnetic interference and no interference. Through construction of the first detection quantity based on absolute tracking loop output, subtle fluctuations in tracking loop output can be accurately captured; the second detection quantity of ATLO-MV obtained through mobile variance enhancement processing effectively improves detection sensitivity and anti-noise performance; finally, a new type of detection algorithm is constructed through multi-satellite joint processing (ATLO-MV-MSC) of ATLO-MV, the distinction between no interference, natural electromagnetic interference and spoofing attacks is realized, and the pain point of fuzzy judgment existing in traditional algorithms is solved.