摘要:
In order to image test objects by electromagnetic waves, in particular millimetric waves, a test object is illuminated with the electromagnetic waves, the scattered waves are received, and are evaluated for a representation of the test object in the form of an image based on the principle of “synthetic aperture radar” (SAR). In order to allow as large an area as possible to be imaged with high resolution in a short time, the phase centres of the transmitting and receiving antennas are, according to the invention, moved on a circular path parallel to the respective digital focus planes of the imaging system, and are at the same time shifted linearly in a further direction parallel to the respective focus plane. The method can be used for monitoring people for suspicious objects, for example for monitoring airline passengers at an airport.
摘要:
A method for imaging test objects by means of electromagnetic waves, in particular for the purpose of checking individuals for suspicious articles, in which method the test object is illuminated by electromagnetic waves, the scattered waves are received and evaluated for an imaginal representation of the test object on the basis of the synthetic aperture principle (SAR). A synthetic aperture is produced by the waves output by an antenna being concentrated initially in spatial terms, the point of high concentration being moved on a reflector along a circle.
摘要:
In order to image test objects by electromagnetic waves, in particular millimetric waves, a test object is illuminated with the electromagnetic waves, the scattered waves are received, and are evaluated for a representation of the test object in the form of an image based on the principle of “synthetic aperture radar” (SAR). In order to allow as large an area as possible to be imaged with high resolution in a short time, the phase centres of the transmitting and receiving antennas are, according to the invention, moved on a circular path parallel to the respective digital focus planes of the imaging system, and are at the same time shifted linearly in a further direction parallel to the respective focus plane. The method can be used for monitoring people for suspicious objects, for example for monitoring airline passengers at an airport.
摘要:
1. A device and a method for the improved directional estimation and decoding by means of secondary radar signals. 2.1 Radio-based positioning systems on the basis of secondary radar signals are known. For this purpose special receiver systems are utilized for estimating the direction, and special receiver systems are utilized for decoding secondary radar signals. In particular, a secondary radar system is absent, which, among others, takes into consideration any shortcomings of the hardware used, such as coupled antenna elements, different low-end impedances, deviating distances between the antenna elements, manufacturing and installation tolerances, and the like. 2.2 The device for directional estimation and/or decoding secondary radar signals according to the invention comprises the following: —at least one array A comprising M antenna elements AE—an amplifier LNA and bandpass filter F1 combination connected to a plug-in connector S of the respective antenna element AE, at the filter output of said combination a first linear amplifier V1 being connected for amplifying the band-limited signal, —a mixer M connected to the first linear amplifier V1 for the frequency conversion into a ZF region, —a second linear amplifier V2 and bandpass filter F2 combination connected to the mixer output for amplifying and limiting the bandwidth of the signal in the ZF region, —a first analog-to-digital converter AD1 connected to the second bandpass filter F2 for scanning and quantifying the filter output signal, —a configurable signal processor FPGA/DSP connected to the first analog-to-digital converter AD1, said processor being connected to a PLL-VCO circuit for controlling the mixer frequency and receiving the data for processing, and—a
摘要:
The invention relates to a method for determining a distance (r) to a target object (200) consisting in transmitting electromagnetic waves in the form of a transmission signal (120a) by a transmitter (111a), receiving at least one part of said transmission signal (120a) reflected by a the target object (200) in the form of a reception signal (120c, 120d) by receiving device (111b) and evaluating the reception signal (120c, 120d) according a reference signal (1230b) which has a known phase difference with respect to the transmission signal (120a) and a frequency equal to the frequency thereof. The reference (120) and reception (120c, 120d) signal frequencies are reduced in a frequency divider (113) with the same predefined divider factor (x) while preserving the existing phase difference between the reference signal (120b) and the reception (120c, 120d) signal in such a way that a reduced frequency reception signal (120b′) and a reduced frequency reception signal (120d) are obtained. The frequency difference between the reduced frequency reception signal (120b′) and reduced frequency reception signal (120d′) is evaluated in order to determine the distance (R).
摘要:
A device and a method for the improved directional estimation and decoding by means of secondary radar signals. The device includes: at least one array of antenna elements; a low noise first amplifier and bandpass filter combination connected to a plug-in connector S of the respective antenna elements; a first linear amplifier being connected at a filter output of said combination for amplifying the band-limited signal; a mixer connected to the first linear amplifier for the frequency conversion into a ZF region; a second linear amplifier and bandpass filter combination connected to the mixer output for amplifying and limiting the bandwidth of the signal in the ZF region; a first analog-to-digital converter connected to the second bandpass filter; a configurable signal processor connected to the first analog-to-digital converter; and a processing unit connected to the configurable signal processors.
摘要:
An apparatus and a method for determining a distance (r) to a target object (200) proposes transmitting electromagnetic waves in the form of a transmission signal (120a) by a transmitter (111a), receiving at least one part of said transmission signal (120a) reflected by a the target object (200) in the form of a reception signal (120c, 120d) by receiving device (111b) and evaluating the reception signal (120c, 120d) according a reference signal (1230b) which has a known phase difference with respect to the transmission signal (120a) and a frequency equal to the frequency thereof. The reference (120) and reception (120c, 120d) signal frequencies are reduced in a frequency divider (113) with the same predefined divider factor (x) while preserving the existing phase difference between the reference signal (120b) and the reception (120c, 120d) signal in such a way that a reduced frequency reception signal (120b′) and a reduced frequency reception signal (120d) are obtained. The frequency difference between the reduced frequency reception signal (120b′) and reduced frequency reception signal (120d′) is evaluated in order to determine the distance (R).