422 results about "Step frequency" patented technology

Methods and apparatus are presented which reduce the overall cost and increase the imaging capability for medium and long range automotive radar sensing applications through the combination of a high signal-to-noise ratio and wide dynamic range radar waveform and architecture, antenna arrangement, and a low cost packaging and interconnection method. In accordance with aspects of the present invention, one way a high signal-to-noise ratio and wide dynamic range imaging radar with reduced cost can be achieved is through the combination of a pulsed stepped-frequency-continuous-wave waveform and electrically beam-switched radar architecture, utilizing a planar package containing high-frequency integrated circuits as well as integrated high-frequency waveguide coupling ports, coupled to a multi-beam waveguide-fed twist-reflector narrow beam-width antenna. Other methods and apparatus are presented.

Methods and apparatus are presented that reduce the overall system cost for automotive radar sensing applications through reduction of the number of the radar sensors required. In accordance with aspects of the present invention, one way sensor count reduction can be achieved is through the combination of target range, direction, and velocity determination capability with wide angular field of view coverage within a single sensor unit. One embodiment combines a transmit-pulsed, linearly stepped frequency modulated, transmit power limited radar architecture with a spatially separated receiver antenna array, intermediate frequency down-conversion, and a digital multi-zone monopulse (DMM) signal processing technique for high-resolution target range, velocity, and azimuth angle determination and fast update rate capability in a low cost, mass-production-capable design.

A ground-penetrating radar comprises a software-definable transmitter for launching pairs of widely separated and coherent continuous waves. Each pair is separated by a constant or variable different amount double-sideband suppressed carrier modulation such as 10 MHz, 20 MHz, and 30 MHz Processing suppresses the larger first interface reflection and emphasizes the smaller second, third, etc. reflections. Processing determines the electrical parameter of the natural medium adjacent to the antenna.

The modulation process may be the variable or constant frequency difference between pairs of frequencies. If a variable frequency is used in modulation, pairs of tunable resonant microstrip patch antennas (resonant microstrip patch antenna) can be used in the antenna design. If a constant frequency difference is used in the software-defined transceiver, a wide-bandwidth antenna design is used featuring a swept or stepped-frequency continuous-wave (SFCW) radar design.

The received modulation signal has a phase range that starts at 0-degrees at the transmitter antenna, which is near the first interface surface. After coherent demodulation, the first reflection is suppressed. The pair of antennas may increase suppression. Then the modulation signal phase is changed by 90-degrees and the first interface signal is measured to determine the in situ electrical parameters of the natural medium.

Deep reflections at 90-degrees and 270-degrees create maximum reflection and will be illuminated with modulation signal peaks. Quadrature detection, mixing, and down-conversion result in 0-degree and 180-degree reflections effectively dropping out in demodulation.

A mobile software application may issue an alert when a user is not achieving a heath objective based on track movement of a mobile computer system that is running the application and being carried by the user and physical characteristics of the user. The software application may map information about the physical characteristics of the user to a user model and determine the energy being expended by the user based on the user model and movement information provided by the mobile computer system. The software application may determine the frequency of steps taken by the user by: bandpass filtering a time domain signal that is representative of the movement, transforming the filtered time domain signal into a frequency domain signal, and equating the step frequency with the frequency of the highest peak in the frequency domain signal.

The invention discloses a digital modulation signal generator based on DDS; a modulation source selection switch selects modulation waveform data and outputs the same to a frequency modulation operation circuit, is multiplied by a frequency step factor Kstep, and then pluses an initial frequency control word Kstart and serves as a frequency control word KH of high-speed DDS; the high-speed DDS is produced under the control of a sampling clock clkH, the frequency control word KH is accumulated in a high-speed phase accumulator, the high MH bit thereof is output to the high-speed waveform RAM and serves as a data address of the high-speed waveform RAM, outputs modulation waveform data, passes through D/A conversion and a low-pass filter and outputs digital modulation signals corresponding to the modulation waveform. The digital modulation signal generator based on DDS can regulate the modulation signal frequency only by changing a low-speed frequency control word KL, can change the modulation waveform only by changing the storage waveform data of the low-speed waveform RAM, can changing the carrier frequency and the modulation depth only by regulating the initial frequency control word Kstart and the step frequency control word Kstep, and has high precision and high switching speed because the control words are digital signals.

The invention discloses a determination method and a device of movement distance. According to the invention, APP in a mobile terminal is used for acquiring a plurality of state corresponding relationships, step number corresponding relationships, and distance corresponding relationships; step length key values are determined based on the plurality of the state corresponding relationships, the step number corresponding relationships, and the distance corresponding relationships, and are stored in a memorizer of the mobile terminal; when it is determined that positioning information of the mobile terminal is not capable of satisfying positioning requirements, real-time movement states and real-time step frequency of the user are determined; the real-time movement states and the real-time step frequency are taken as matches, and real-time matching with the step length key values stored in the memorizer is carried out; user movement distance is calculated based on the step length of matched step length key values, and the movement distance is accurately calculated based on step length and step frequency. The determination method is capable of increasing accuracy of movement distance determination using APP when it is impossible to relay on the positioning information, and user experience is excellent.

A unique hardware architecture that combines short pulse, stepped frequency and centerline processing. The inventive architecture implements a radar system having a transmitter for transmitting short pulses, each pulse being stepped in frequency and a receiver receiving the pulses and providing an output signal in response thereto. In the illustrative embodiment, the transmitter includes a frequency source, an RF switch coupled to the source and a controller for controlling the RF switch. The receiver includes a signal processor implemented with a center line roughing filter. The signal processor has multiple channels each of which has a range gate and a digital filter. The digital filter includes a Fast Fourier Transform adapted to output a range Doppler matrix.

The invention discloses a self-adaptive speed regulation system of running device based on a flexible array pressure transducer, comprising the flexible array pressure transducer, a data collection transmission module, a tablet computer, a computer control program, and a motor drive module, wherein the motor drive module is connected with a motor for driving the motor to rotate, and the motor drives the running belt of the running device to rotate. In the invention, stride frequency, stride length, ground-touching time, air time, rearward thrust and other parameters of a runner when in running can be obtained by installing the flexible array pressure transducer on the upper side of the running plate of the running device; acceleration can be calculated by an established relational model of difference of acceleration and the step length between two adjacent steps, the step frequency, the component force of the rearward thrust along the moving directing of the running belt, time for completing two steps (the ground-touching time + the air time), and the weight of the runner; a control command is sent to the motor drive module according to the obtained acceleration; and the motor rotation speed is adjusted; therefore, the speed self-adaption of the running device is realized.

The invention discloses a step counting method and apparatus based on a tri-axial acceleration sensor. The method comprises the following steps: detecting a peak point and a valley point in a waveform of a target acceleration signal, determining the peak point and the valley point as well as the number of the peak points and the number of the valley points according to a detection result, using the number of the peak point or the valley point as a step frequency feature, determining a motion type of a person according to the step frequency feature, determining a target peak point and a target valley point in the waveform of the target acceleration signal by using a preset time window and preset peak-valley value window corresponding to the motion type, and using the number of the target peak points or the number of the target valley points as the step number of the person motion. According to the method, different motion states of the person can be judged by extracting the step frequency feature of the person, and the interference can be effectively eliminated by using the characteristic that each motion state correspondingly has different time windows and peak-valley value windows, so that the calculated step number is more accurate.

The invention discloses an indoor fusion positioning method based on multi-features. The whole process of the method is divided into three parts such as Wi-Fi fingerprint probability calculation, inertial navigation calculation and particle filtering fusion, wherein the Wi-Fi fingerprint probability calculation uses a cosine similarity matching algorithm, the inertial navigation calculation is divided into three parts such as step number calculation, step size calculation and walking direction estimation, the step number calculation uses methods such as walking detection, center moving equating, window wave peak detection, dynamic time regularization, derivative analysis filtering and wave peak resurrection, the step size calculation uses a step size and step frequency relationship model, the walking direction estimation uses the time and frequency zone analysis of a horizontal direction acceleration and strategy adjusting based on a gravity direction, and finally in the particle filtering fusion part, the hidden markov model constructed based on the inertial navigation and the Wi-Fi fingerprint probability uses the particle filtering method and combines with the map information to calculate the position probability so as to finally obtain the positioning result.

The transfer function of the communication channel in a mud pulse telemetry system is determined by sending a known signal through the channel and spectral analysis of the received signal. The known signal may be a chirp signal or a stepped frequency signal. Based on the determined transfer function, operating parameters of the pulser are adjusted.

The invention discloses a frequency synthesizer and a frequency synthesis method. The frequency synthesizer comprises: a large-stepping phase lock loop and a direct digital frequency synthesizer, an orthogonal mixer and a tracking phase lock loop. The orthogonal mixer is connected with the large-stepping phase lock loop and the digital frequency synthesizer respectively for mixing the frequency generated by the large-stepping phase lock loop and the low frequency generated by the direct digital frequency synthesizer to generate a single-sideband single tone; the tracking phase lock loop is connected with the orthogonal mixer for receiving the single-sideband single tone output by the orthogonal mixer and filtering the sideband leakage and oscillation leakage of the signal. The invention provides a frequency synthesizer with wide band width, small stepping, low stray and low noise and a frequency synthesis method. The invention has simple hardware structure and is easy to accomplish.

A time needed until measurement values are obtained in a two-frequency continuous wave radar systems is reduced.

A target object detection system (1) that emits to target objects transmission signals (22), as transmission waves (23), whose frequencies have been modulated successively into a plurality of stepped frequencies, and receives echoes (24) of the transmission waves (23) reflected from the target objects, thereby to calculate relative velocities of the target objects by frequency-analyzing reception signals (25) obtained from the received echoes (24). The target object detection system (1) includes: a frequency modulation means (2) that executes a plurality of times frequency-modulation processes to successively modulate the transmission signals (22) into those of the stepped frequencies, within a minimum measurement time in which a desired velocity resolution is achieved; and a frequency-analysis means (6) that frequency-analyzes throughout the plurality of frequency-modulation processes the reception signals (25) obtained by receiving the echoes (24) of the transmission signals (22) modulated into those of an identical stepped frequency in the plurality of frequency-modulation processes iterated by the frequency-modulation means (2).

A stepped-frequency chirped waveform improves SAR groundmapping for the following reasons. Range resolution in SAR image is inversely proportional to the transmitted signal bandwidth in nominal SAR systems. Since there is a limit in the transmitted bandwidth that can be supported by the radar hardware, there is a limit in range resolution that can be achieved by processing SAR data in conventional manner. However, if the frequency band of the transmitted signal is skipped within a group of sub-pulses and received signal is properly combined, the composite signal has effectively increased bandwidth and hence improvement in range resolution can be achieved. The proposed new and practical approach can effectively extend the limit in range resolution beyond the level that is set by the radar hardware units when conventional method is used.

A method and structure receives a desired rotational speed and/or step frequency for an electric motor. If the desired rotational speed is above a predetermined limit, the method performs closed-loop mode control of coil current of the electric motor by varying the average voltage supplied to the electric stepper motor according to observed feedback current from the current feedback loop connected to the electric stepper motor. To the contrary, if the desired rotational speed is not above the predetermined limit, the method performs open-loop mode control of coil current of the electric stepper motor by setting the average voltage supplied to the electric stepper motor according to values computed from the step frequency, irrespective of the observed feedback current from the current feedback loop.

The invention discloses a terahertz inverse synthetic aperture radar imaging method based on a frequency modulation step frequency to solve the problem that in the prior art, the range resolution and the direction resolution of inverse synthetic aperture radar imaging in the microwave band are not high. The method includes the steps of firstly, obtaining a terahertz pulse echo signal; secondly, conducting pulse compression; thirdly, synthesizing a broadband; fourthly, conducting windowing and correcting; fifthly, conducting distance Doppler imaging; sixthly, obtaining an imaged picture. According to the method, the characteristic that the terahertz wave has the high frequency and the broadband is combined with the frequency modulation step frequency system so that the high-resolution terahertz inverse synthetic aperture radar imaging can be achieved through the method of synthesizing the broadband.

The invention relates to a system for recognizing human gait, real-time monitoring energy consumption thereof and guiding exercise training thereof, comprising a functional innersole, a data storage display system and a health auxiliary guidance system. The system is characterized in that the functional innersole comprises an amorphous wire pressure sensor measuring human pressure and a data acquisition processing system which are embedded; the data storage display system sets system initial parameters and individual parameters through the input of keys and sends the parameters to the data acquisition processing system in the functional innersole through a wireless communication module; the data of the data acquisition processing system are wirelessly sent to the data storage display system, and a display interface on the data storage display system displays the information such as gait, step number, step frequency, energy consumption, time for exercise, and the like; and the data stored in the data storage display system are uploaded to a personal computer, and energy metabolism analysis for an exerciser is carried out and training guidance and training reference are provided under the help of the health auxiliary guidance system in the personal computer. The invention has low energy consumption, high sensitivity, quick response time, high anti-interference ability and low cost.

The invention provides a combined positioning method based on inertial navigation, wi-fi or bluetooth signal fingerprints and an indoor electronic map, and can be widely applied in indoor positioning and seamless combination of indoor and outdoor positioning. The combined positioning method is characterized by comprising the steps: 1) coarse positioning is performed via the wifi or bluetooth network, then through an inertial navigation system of an intelligent terminal and with combination of the map, a precise position of a customer is obtained, and a walking track of the customer is real-timely and continuously obtained; 2) based on formation and use of the electronic map of an indoor planar graph, an indoor electronic map labeling method is included; 3) a particle filtering algorithm combining the several factors together includes detection of a moving state, detection and adjustment of the step length, the step direction and the step frequency, adaption for the electronic map and the wifi (bluetooth) signal fingerprints and the like; 4) based on a map matching algorithm, a correct and accurate walking path is guaranteed; and 5) the terminals not only include intelligent mobile phones and panel personal computers and also include intelligent wearable devices.

The invention relates to a stable ground moving/static target tracking method for airborne radar. According to the method, nonlinear frequency-modulated and stepped-frequency signals are simultaneously emitted to respectively detect moving/static targets according to the characteristics of the moving/static targets; the nonlinear frequency-modulated signals are mainly used for detecting the moving targets, and the stepped-frequency signals are mainly used for detecting the static targets; one-time point trajectories of the moving/static targets on the ground can be simultaneously obtained in one scan frame of the radar. Compared with the traditional methods, the method has the advantages that the moving/static targets on the ground can be noticed simultaneously, the overall situation of the targets on the ground is reflected, continuous tracking can be carried out when the targets become static from moving or become moving from static, and the continuity and stability of tracking of the moving/static targets on the ground are guaranteed.