Abstract: The present disclosure relates to a method for determining an angle of arrival, AoA, of received radio frequency, RF, measurement signals. The method comprises obtaining measurement data based on the received RF measurement signals from an antenna array, wherein the RF measurement signals are representative of multiple frequency channels. The method further comprises determining power spectra, comprising determining at least one power spectrum for each of the multiple frequency channels by using the measurement data. The method further comprises providing a machine learning algorithm, which is pre-trained to determine an AoA based on power spectra of multiple frequency channels. The method further comprises determining the AoA of the received RF measurement signals by using the machine learning algorithm and the determined power spectra.

Abstract: A system for tracking multiple projectiles includes a first radar device aimed so that a field of view of the first radar device covers at least a portion of a target area into which projectiles are to be launched from a plurality of launch locations and a processor receiving data from the radar and identifying from the data tracks of a plurality of projectiles. The processor determines for each projectile track identified a specific one of the launch locations from which the projectile was launched and provides to the launch location associated with each projectile data corresponding to a trajectory of the projectile.

Abstract: A system and method to eliminate false detections in a radar system involve arranging an array of antenna elements into two or more sub-arrays with a spacing between adjacent ones of the antenna elements of one of the two or more sub-arrays being different than a spacing between adjacent ones of the antenna elements of at least one other of the two or more sub-arrays. The method includes receiving reflected signals at the two or more sub-arrays resulting from transmitting transmit signals from the antenna elements of the two or more sub-arrays, and processing the reflected signals to distinguish an actual angle from the radar system to an object that contributed to the reflected signals from ambiguous angles at which the false detections of the object are obtained. A location of the object is determined as a result of the processing.

Abstract: Systems and methods to identify an object using a radar system involve arranging an array of antenna elements into two or more subarrays with a tilt angle relative to each other. Each of the two or more subarrays includes two or more antenna elements among the array of antenna elements. A method includes receiving reflected signals at each of the two or more subarrays resulting respectively from transmitting transmit signals from the two or more subarrays, and processing the reflected signals at each of the two or more subarrays to obtain an amplitude associated with each azimuth angle in a range of azimuth angles. A location of the object is determined as the azimuth angle in the range of azimuth angles at which the amplitude exceeds a threshold value.

Abstract: The disclosed method may include (1) receiving, at a receiving vehicle from a first transmitting vehicle, a first wireless signal carrying first data indicating a first location of the first transmitting vehicle, (2) determining a first bearing from which the first wireless signal is received at the receiving vehicle, (3) receiving, at the receiving vehicle from a second transmitting vehicle, a second wireless signal carrying second data indicating a second location of the second transmitting vehicle, (4) determining a second bearing from which the second wireless signal is received at the receiving vehicle, and (5) determining a receiving location of the receiving vehicle by triangulation using the first location, the first bearing, the second location, and the second bearing. Various other methods, systems, and computer-readable media are also disclosed.

Abstract: Systems, methods, and devices are disclosed herein for Doppler based position estimation. Systems may include an antenna configured to receive a radio frequency (RF) signal from an emitter, and configured to generate an output signal based on the received RF signal. Systems may also include a receiver configured to receive the output signal from the antenna. The receiver may include one or more processors configured to identify a plurality of initial conditions for a plurality of state variables associated with the emitter, obtain a measurement of the RF signal from the emitter and an estimate of an uncertainty associated with the measurement, and generate an output based, at least in part, on an updated estimate of the plurality of state variables, the output identifying a position, velocity, and carrier frequency of the emitter. Systems may also include a communications interface configured to communicatively couple the antenna with the receiver.

Abstract: A system and method that can determine the direction of origin within 360 degrees around an antenna array for an emitted signal with a high degree of accuracy, even when the array is installed in a corrupted or “unclean” environment. Further, the provided system and method can provide a more accurate indication of direction despite polarization of the detected signal. Finally, the provided system and method can provide accurate results from phase measurements, amplitude measurements, or both phase and amplitude measurements, from an emitted signal where a phase network can be used to tailor the amplitude and phase variations versus spatial angle to best match the receiver measurement accuracies.

Abstract: An antenna receiver has antenna elements that are arranged in an array and spaced apart from each other at a distance greater than one-half wavelength of the highest operating frequency of a signal that is to be detected by the antenna receiver. The antenna receiver has geolocation logic that uses the inter-element phase difference measurements to obtain a location of the signal source. The change in the inter-element phase differences enables the elements to be spaced apart at great distances, which is beneficial for the physical construction of the platform, as the elements may be easily placed at convenient locations for conformal aerodynamic properties.

Abstract: Machine-readable media, methods, apparatus and system for automated vehicle with target localization are disclosed. In some embodiments, the system may comprise at least three receivers on a first vehicle, wherein each of the at least three receivers is to receive a first signal of a first wavelength from a transmitter of a second vehicle; and a controller to calculate one or more first location candidate of the second vehicle with respect to the first vehicle, at least in part based on differences among first signal path lengths for the first signal to travel from the transmitter to each of the at least three receivers.

Abstract: The present invention generally relates to an electromagnetic field vector sensing receive antenna array system for installation and deployment on a structure. A multipolarized array of collocated antenna elements is used to provide calibrated amplitude and phase radiation patterns with monopole, dipole, and loop modes generated from crossed loops connected to a beamformer. The invention has applications for installation and deployment on a tower, balloon, satellite for radio frequency sensing and location of low-frequency galactic emissions. The novel receive antenna array system comprises a multipolarized vector sensor antenna array. The disclosed direction-finding vector sensor can be installed and deployed on a structure and can detect and locate radio frequency emissions from galactic sources. The key system components of the receive antenna array system consist of deployable antennas, receivers, signal processing computer, and communications link.

Abstract: A method and receiver for determination of angle of arrival in one or two planes of a beam received at an antenna array comprising at least two pairs of antenna elements are provided. In some embodiments, a method includes computing a pair of difference signals, each difference signal being computed from signals from a different one of the at least two pairs of antenna elements. The method further includes determining a directional angle of arrival of the beam in one plane based on the pair of difference signals.

Abstract: In an embodiment, an antenna subsystem includes a sparse receive antenna and an electronically steerable transmit antenna. The sparse receive antenna includes an array of receive elements each configured to receive a respective signal having a wavelength and each spaced apart from each adjacent one of the receive elements by a respective first distance that is more than one half of the wavelength. And the electronically steerable transmit antenna includes an array of transmit elements each configured to radiate a respective signal having the wavelength and each spaced apart from each adjacent one of the transmit elements by a respective second distance that is less than one half of the wavelength. To reduce aliasing, such an antenna subsystem can be operated to filter, spatially, a receive beam pattern generated by the receive antenna with a transmit beam pattern generated by the transmit antenna.

Abstract: Techniques are presented herein for computing angle-of-arrival estimates while switching antenna states during a packet unit for the general Orthogonal Frequency Division Multiple Access (OFMDA) case (including a single user). A wireless device computes channel estimates throughout the entire frame and not only during the training symbols. Consequently, the wireless device computes channel estimates for all antennas in its array within a single frame instead of having to wait for multiple frames.

Abstract: A method is disclosed for determining an angle of arrival of an incident plane wave received by an antenna array. The method includes receiving signals from a plurality of antenna receiving channels, determining a set of possible angles of arrival of the incident plane wave based on the signals received at the plurality of receiving channels, measuring a pulse delay of the incident plane wave between the signals received at the plurality of receiving channels, and calculating the angle of arrival of the incident plane wave based on the set of possible angles of arrival and the measured pulse delay.

Abstract: Each of a plurality of signal measurement circuits is included in a terminal. Each measurement circuit receives a signal from a transmitter in a satellite and measures characteristics of the signal. A computer is programmed to receive data from the signal measurement circuits. The data indicates characteristics of the signal, including a strength of the signal. The computer determines an initial estimated satellite pointing direction, and generates subsequent estimated satellite pointing directions. For the initial and subsequent estimated pointing directions, the strength of the signal received by each measurement circuit is compared with an expected strength of the signal based on the respective estimated pointing direction. Each subsequent estimate is based at least in part on the comparison of the immediately preceding estimate. Based on the comparisons, the computer estimates a current satellite pointing direction.

Abstract: A device for estimating a two-dimensional direction of arrival (DOA) of an electromagnetic beam includes an antenna system, and a signal processor operatively coupled to the antenna elements of the antenna system. The antenna system includes a plurality of antenna elements arranged in a rectangular planar array and configured to receive signal components of the electromagnetic beam. The signal processor estimates the two-dimensional DOA of the electromagnetic beam based on relative phases of the signal components of the electromagnetic beam.

Abstract: Provided is an apparatus for detecting airborne objects comprising a kill vehicle bus having a radar sensor. The radar sensor may be an interferometric sensor comprising a plurality of transmit-receive arrays. Each of the transmit-receive arrays may be adapted to be stowed in a stowed position in or on the kill vehicle bus, and may be adapted to be expandable from the stowed position to an operable position.

Abstract: Techniques are presented herein for computing angle-of-arrival estimates while switching antenna states during a packet unit for the general Orthogonal Frequency Division Multiple Access (OFMDA) case (including a single user). A wireless device computes channel estimates throughout the entire frame and not only during the training symbols. Consequently, the wireless device computes channel estimates for all antennas in its array within a single frame instead of having to wait for multiple frames.

Abstract: An antenna array can be quickly and efficiently designed to meet specified performance criteria. A system can be configured to receive various performance criteria as inputs, and from these inputs, identify how elements of an antenna array should be arranged so that the antenna array will meet the performance criteria. An iterative process can be performed to identify at least one arrangement of elements that will best meet the performance criteria while also complying with specified structural constraints.

Abstract: A method for improving direction finding and geolocation error estimation in direction finding and geolocation systems is disclosed. The corresponding phases of the received signals are determined. After an initial target estimation point of the received signals has been identified, the initial target estimation point is projected onto the earth's surface. A search grid having multiple grid points is then overlaid on the projected initial target estimation point, surrounding the projected initial target estimation point. The phase of signals emitting from a theoretical emitter located at each of the grid points of the search grid is estimated. Correlation coefficients between the estimated phases of the emitting signals and the determined phases of the received signals are determined. An error ellipse can be generated around one of the grid points having the highest correlation coefficient, and a source emitter is likely to be located within the error ellipse.

Abstract: A system and method for recovering from a failure during the position tracking of an RF-transmitting device includes tracking the position of the radio frequency (RF) transmitting device based on RF signals emitted by the RF-transmitting device. If the tracking loses the position of the RF-transmitting device, new phase difference data are calculated from the RF signals transmitted by the RF-transmitting device and received at four or more antennas. A subset of candidate position solutions for evaluation is identified based on the new phase difference data. One or more of the candidate position solutions in the subset is evaluated to find an acceptable position solution. The tracking of the position of the RF-transmitting device resumes using the acceptable position solution.

Abstract: A system and method for testing the integrity of signals incoming to a satellite navigation system. The method is implemented with an array of antenna elements, and a receiver connected to each antenna element. The receivers simultaneously and continuously make measurements on all tracked signals. Each receiver measures the carrier phase of an incoming signal. Based on the carrier phase differences between antenna elements and the distance between them, the azimuth and elevation of the signal source can be calculated. This measured angle of arrival can then be compared to an expected angle of arrival to determine if the signal source is legitimate. The system and method can be also applied to determining the angle of arrival of sources of interference, and to mitigating the effects of both illegitimate and interfering signals.

Abstract: A cover assembly is provided, for use with an instrument package having a common aperture. The cover assembly includes an inner cover member and an outer radome member. The inner cover member is substantially transparent to electromagnetic (EM) radiation of at least a first wavelength range. The radome member is configured for selectively and reversibly covering the inner cover member and transparent to EM radiation of at least a second wavelength range different from the first wavelength range. The second wavelength range includes a radio frequency wavelength range. The outer radome member is configured for being mounted in overlying relationship with respect to the common aperture of the instrument package. The radome member is configured for being initially in overlying relationship with respect to the inner cover member and for being selectively removed from the overlying relationship with respect to the inner cover member at least during flight conditions.

Abstract: A method for estimating an angle of arrival of multiple targets moving at a high speed includes defining a range and a resolving power of an angle of arrival and an angular velocity of a plurality of direction finding targets (S1100), setting minimum values of the angle of arrival and the angular velocity within the range to be a set angle of arrival and a set angular velocity (S1200), and adding angle of arrival resolution and angular velocity resolution to the set angle of arrival and the set angular velocity, respectively, deriving a two-dimensional spatial spectrum of a transformed incident signal using a pre-steered vector until the angle of arrival and the angular velocity become a maximum value, and estimating a peak value of the spatial spectrum as a measured angle of arrival and a measured angular velocity of the target (S1300).

Abstract: Methods and systems are provided for modifying spacing in between a plurality of antenna dipole columns on an antenna associated with a wireless communications network. A first signaling technology currently employed by a base station is determined, where the first signaling technology requires each of the antenna dipole columns to be separated from one another by a first distance. It is then determined that a second signaling technology is to be employed by the base station, the second signaling technology requiring each of the antenna dipole columns to be separated from one another by a second distance. A signaling message is communicated to a movement mechanism, causing at least one of the antenna dipole columns to move so that the columns are spaced at the second distance from one another.

Abstract: Systems, methods, and devices enable spectrum management by identifying, classifying, and cataloging signals of interest based on radio frequency measurements. In an embodiment, signals and the parameters of the signals may be identified and indications of available frequencies may be presented to a user. In another embodiment, the protocols of signals may also be identified. In a further embodiment, the modulation of signals, data types carried by the signals, and estimated signal origins may be identified.

Abstract: A method for detecting a radioactive source moving on a linear path substantially parallel to an alignment of N detectors. The method includes: forming N×Nt pulse counting values Mi,t (i=1, 2, . . . , N and t=1, 2, . . . , Nt) from N×Nt detection signals delivered by the N detectors in the form of a succession over time of Nt sets of N signals simultaneously detected by the N detectors over a same duration ?t, a pulse counting value representing a number of pulses detected by a detector over a duration ?t; and computing, using a computer: a set of Nt correlation products Rt, a static mean R of the N×Nt counting values, a correlation condition for each correlation product Rt.

Abstract: A method for estimating a boundary for a future location of a moving object includes: receiving location information about two previous locations of the moving object represented by a first and a second elliptical error probabilities (EEPs); representing each of the EEPs as a conic section via an implicit quadratic equation; defining four tangent lines from the implicit quadratic equation, each tangent line being tangent to both of the EEPs; determining two transverse tangent lines from the four tangent lines; forming a cone in a direction from the first EEP to the second EEP from the two transverse tangent lines; and estimating the boundary of the future location of the moving object as a first side of the cone formed by a first transverse tangent line and a second side of the cone formed by a second transverse tangent line, of the two transverse tangent lines.

Abstract: In one embodiment the quantizer includes a signal-to-phase converter configured to generate a phase signal according to an input signal and a phase difference digitization block configured to generate a quantization output according to differentiated samples of the phase signal, where the phase signal generated by the signal-to-phase converter has a sinusoidal shape.

Abstract: A receiver with a local oscillator, a quadrature modulator, a first mixer and a second mixer, wherein a first input of the quadrature modulator is connected to a second signal input of the receiver circuit and a second input of the quadrature modulator is connected to the local oscillator. Further, a first input of the first mixer is connected to a first signal input of the receiver circuit, a second input of the first mixer is connected to an output of the quadrature modulator, and an output of the first mixer is connected to a first signal output of the receiver circuit. A first input of the second mixer is connected to the second signal input, a second input of the second mixer is connected to the output of the quadrature modulator, and an output of the second mixer is connected to a second signal output of the receiver circuit.

Abstract: A system of geographical location of at least one radio signal transmitter located on the Earth's surface including: a set of satellites equipped with receiving antennas adapted for receiving said signals, forming a main extended interferometry device; an intersatellite relative metrology device for determining the relative positions of said satellites to one another, including at least one dedicated sensor for each satellite, and intersatellite communication means; a device for dating said received signals from said determining of the relative positions of said satellites to one another, issued by said intersatellite relative metrology device; a secondary interferometry device including at least one set of at least three antennas of a satellite; a ground base station; a device for transmitting measurements acquired on the satellites to the ground base station; and means of determining an absolute position of at least one of the satellites.

Abstract: An interferometer estimates at least one interferometric parameter of one or more signals emitted from a source. The interferometer has an array of antennas and at least one phase detector configured to determine a plurality of phase measurements of the one or more source signals. A combined estimator processes the plurality of phase measurements to provide estimates of at least one sought parameter, representing the at least one interferometric parameter, and at least one noise parameter associated with the plurality of phase measurements. A postprocessor processes estimates of the at least one sought parameter based on at least one noise parameter received from the combined estimator to improve an estimate of the at least one interferometric parameter. The combined estimator is configurable to produce a maximum likelihood estimate of the at least one sought parameter using at least one noise parameter calculated based on the plurality of phase measurements.

Abstract: A sensing system includes integrated sensor locating capability. Sensors can transmit spread spectrum encoded data pulses which are received at mobile nodes. Based on time of arrival information and known locations of the mobile nodes, locations of the sensors can be determined.

Abstract: A maintenance system for an assembly comprises a storage medium containing an as-built computer-aided design model of the assembly, a displaying means for displaying the as-built computer-aided design model, a metrology device for measuring a location of at least one characteristic of the assembly and creating as-built data regarding the location, and a replacing means for replacing a part of the assembly with a replacement part. The replacing means determines the location for the replacement part on the assembly by analyzing the as-built computer-aided design model and the data created by the metrology device.

Abstract: A method for determining rotation bias in a sensor using a cooperative target that includes receiving, via a processor, sensor data acquired in a field of view of a sensor at a plurality of points in time. The method also includes receiving, via the processor, position data for a cooperative target travelling along a path through the field of view of the sensor at the plurality of points in time. The method also includes determining, via the processor, a rotation bias in the sensor based on a maximum likelihood estimate performed over the path based on the sensor data and the cooperative target position data.

Abstract: A system of geographical location of at least one radio signal transmitter located on the Earth's surface including: a set of satellites equipped with receiving antennas adapted for receiving said signals, forming a main extended interferometry device; an intersatellite relative metrology device for determining the relative positions of said satellites to one another, including at least one dedicated sensor for each satellite, and intersatellite communication means; a device for dating said received signals from said determining of the relative positions of said satellites to one another, issued by said intersatellite relative metrology device; a secondary interferometry device including at least one set of at least three antennas of a satellite; a ground base station; a device for transmitting measurements acquired on the satellites to the ground base station; and means of determining an absolute position of at least one of the satellites.

Abstract: An apparatus and method for receiving electromagnetic waves using photonics includes a transmission unit transmitting electromagnetic waves in intervals; a time delay unit coupled to the transmission unit and controlling the transmission unit to transmit the electromagnetic waves in the intervals; an antenna receiving the electromagnetic waves reflected from the target; an interferoceiver coupled to the antenna and receiving the electromagnetic waves from the antenna, the interferoceiver comprising an optical recirculation loop to produce replica electromagnetic waves; and a computer identifying the target from the reflected electromagnetic waves.

Abstract: A method of locating a terrestrial emitter of electromagnetic radiation in the midst of a plurality of emitters in a satellite in orbit about the earth which utilizes a location estimation and location probability determination process with respect to each possible emitter site and its corresponding error region and then using both feedback and feed forward interaction between location and phase ambiguity resolution processes to generate resolved phase from emitter location, update emitter location or some or all of the emitters, and subsequently utilizing the probabilities thus determined to produce a single estimate of the desired emitter's location.

Abstract: In a geolocation system for determining a geolocation of a target emitter, a method for determining the geolocation.

Abstract: A method for determining an angle-of-arrival for a detected signal. The method includes the steps of receiving the signal at a first antenna, receiving the signal at a second antenna, generating a plurality of spectral lines based on a complex multiplication of a complex conjugation of the signal received at the first antenna and the signal received at the second antenna, generating a delta phase difference for pairs of the spectral lines using frequency differences, and generating an angle-of-arrival for the detected signal based on an average of the delta phase difference.

Abstract: A method of integrating a detected signal along a given angle of arrival to improve detection. The method includes receiving the signal at a first antenna, receiving the signal at a second antenna, generating a phase difference trajectory based on the signal from the first antenna and the signal from the second antenna, and extracting a signal by integrating the phase difference trajectory over frequency for a plurality of angles of arrival.

Abstract: A method is provided for constructing a histogram to represent the root-mean-squared phase differences for a signal received at pairs of elements in an array. A pair-wise element phase difference (“PEP”) between a signal received at an angle of arrival ?1 and a signal received at an angle of arrival ?2 are determined. The difference ?? between the differential phase measurements at ?1 and ?2 is computed. The process is repeated for all unique pairs of angles (?1, ?2) from 0 to 359 degrees and the results are summed over all PEPs to calculate the root mean squared phase difference ?{square root over (??2(?1,?2))} between two different angles of arrival ?1 and ?2. A two-dimensional histogram is created by pairing the measurements ?{square root over (??2)} and ??, where ??=?2??1.

Abstract: A sparsely populated array of antenna elements on a plane is provided such that the angle of arrival (AoA) measurement for a radiofrequency signal received by the array has high resolution and is non-ambiguous within a 360-degree azimuthal field of view. The array comprises a two-dimensional antenna array developed using fuzzy genetic logic based on specified criteria. In response to one specified set of criteria, the array comprises having a first large element formation combined with a second smaller element formation. The first large element formation supports high DF accuracy while the second smaller cluster facilitates ambiguity resolution.

Abstract: A receiving system includes a combiner configured to receive signals from two or more antenna elements and to generate sum and difference outputs, and a switch configured to sequentially provide the sum and difference outputs as inputs to a receiver.

Abstract: A sparsely populated array of antenna elements on a plane is provided such that the angle of arrival (AoA) measurement for a radiofrequency signal received by the array has high resolution and is non-ambiguous within a 360-degree azimuthal field of view. The array comprises a two-dimensional antenna array developed using fuzzy genetic logic based on specified criteria. In response to one specified set of criteria, the array comprises having a first large element formation combined with a second smaller element formation. The first large element formation supports high DF accuracy while the second smaller cluster facilitates ambiguity resolution.

Abstract: A method of locating a terrestrial emitter of electromagnetic radiation in the midst of a plurality of emitters in a satellite in orbit about the earth which utilizes a location estimation and location probability determination process with respect to each possible emitter site and its corresponding error region and then using both feedback and feed forward interaction between location and phase ambiguity resolution processes to generate resolved phase from emitter location, update emitter location or some or all of the emitters, and subsequently utilizing the probabilities thus determined to produce a single estimate of the desired emitter's location.

Abstract: A method of locating a terrestrial emitter of electromagnetic radiation in the midst of a plurality of emitters in a satellite in orbit about the earth which utilizes a location estimation and location probability determination process with respect to each possible emitter site and its corresponding error region and then using both feedback and feed forward interaction between location and phase ambiguity resolution processes to generate resolved phase from emitter location, update emitter location or some or all of the emitters, and subsequently utilizing the probabilities thus determined to produce a single estimate of the desired emitter's location.

Abstract: A wireless communication method and antenna system for determining the direction of arrival (DOA) of received signals in azimuth and elevation, (i.e., in three dimensions), to form a beam for transmitting and receiving signals. The system includes two antenna arrays, each having a plurality of antenna elements, two first stage multi-mode-port matrices, at least one second stage multi-mode-port matrix, an azimuth phase detector, an elevation amplitude detector, a plurality of phase shifters and a transceiver. The antenna arrays and the first stage multi-mode-port matrices form a plurality of orthogonal omni-directional modes. Each of the modes has a characteristic phase set. Two of the modes' phases are used to determine DOA in azimuth. The second stage multi-mode-port matrix forms a sum-mode and a difference-mode used to determine the DOA of the received signals in elevation. A beam is formed in the direction of the received signals by adjusting the phase shifters.

Abstract: A method to passively locate an emitter using two aircraft to form a large baseline interferometer. The basic two element (two aircraft or helicopters) large baseline interferometer includes self-calibration and allows for various configurations for geo-location of ground-based emitters. The two aircraft large baseline interferometer can measure phase difference of arrival (PDOA) to very precisely locate the emitter in angle. Moving emitters can also be located and tracked using the method of the invention with greater accuracy than can be achieved from a single platform.

Abstract: In an ultra-wideband (“UWB”) receiver, a received UWB signal is periodically digitized as a series of ternary samples. During a carrier acquisition mode of operation, the samples are continuously correlated with a predetermined preamble sequence to develop a correlation value. When the value exceeds a predetermined threshold, indicating that the preamble sequence is being received, estimates of the channel impulse response (“CIR”) are developed. When a start-of-frame delimiter (“SFD”) is detected, the best CIR estimate is provided to a channel matched filter (“CMF”). During a data recovery mode of operation, the CMF filters channel-injected noise from the sample stream. Both carrier phase errors and data timing errors are continuously detected and corrected during both the carrier acquisition and data recovery modes of operation. The phase of the carrier can be determined by accumulating the correlator output before it is rotated by the carrier correction.