EP4073533A1 - Ensemble comportant un système de localisation d'émetteurs et une plateforme mobile; système de localisation d'émetteurs, plateforme mobile et procédé de mesure de direction d'arrivée associés - Google Patents
Ensemble comportant un système de localisation d'émetteurs et une plateforme mobile; système de localisation d'émetteurs, plateforme mobile et procédé de mesure de direction d'arrivée associésInfo
- Publication number
- EP4073533A1 EP4073533A1 EP20820438.8A EP20820438A EP4073533A1 EP 4073533 A1 EP4073533 A1 EP 4073533A1 EP 20820438 A EP20820438 A EP 20820438A EP 4073533 A1 EP4073533 A1 EP 4073533A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- arrival
- location system
- mobile platform
- transmitter location
- module
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
- G01S3/02—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using radio waves
- G01S3/14—Systems for determining direction or deviation from predetermined direction
- G01S3/46—Systems for determining direction or deviation from predetermined direction using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
- G01S3/48—Systems for determining direction or deviation from predetermined direction using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
- G01S3/02—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using radio waves
- G01S3/023—Monitoring or calibrating
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
- G01S3/78—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using electromagnetic waves other than radio waves
- G01S3/782—Systems for determining direction or deviation from predetermined direction
- G01S3/783—Systems for determining direction or deviation from predetermined direction using amplitude comparison of signals derived from static detectors or detector systems
- G01S3/784—Systems for determining direction or deviation from predetermined direction using amplitude comparison of signals derived from static detectors or detector systems using a mosaic of detectors
Definitions
- the field of the invention is that of systems for locating transmitters, for example in electromagnetic listening devices.
- electromagnetic listening consists of receiving and measuring the characteristics of electromagnetic signals coming, for example, from a radar transmitter, then performing various processing operations in order to collect strategic information on the transmitters of these signals. Based on this information, an appropriate response can be provided, such as triggering countermeasures.
- a localization processing makes it possible to obtain information on the position of the transmitter of an electromagnetic signal of interest.
- Such processing is based on a measure of the direction of arrival - DoA ("Direction of Arrival") of the signal of interest.
- a measurement of the DoA makes it possible to position the transmitter on a line of sight.
- the interception of the signal of interest from several distinct positions allows the precise location of the transmitter by cross-checking the various lines of sight obtained.
- the calibration biases limit the number of measurements which can be integrated during the movement of the wearer. If the measurements were independent of each other, the angular precision obtained on a train of N measurements would be VIV times better than for one measurement. Since calibration biases are strongly correlated with measurement on the other, it is not possible to benefit from this gain in integration in V ⁇ V on the accuracy of the location of the transmitter.
- the vector direction finding is limited because the polarization and the site are, a priori, neither known nor measured.
- the antenna environment is not under control.
- Vector direction finding is also very sensitive to noise and only resolves the case of constant or very slowly varying calibration biases. It does not compensate for the evolution of a defect over time.
- the aim of the present invention is to solve this problem.
- the assembly includes one or more of the following characteristics, taken individually or in any technically possible combination:
- the data stream consists of time samples of the incident signal
- the mobile platform comprises: a transmitter of a reference radio signal; and a light source; and the transmitter location system comprises: a DoA estimation device, suitable for estimating the true DoA of the reference radioelectric signal, comprising a camera and a DoA estimation module suitable for estimating a true DoA from the images output from the camera; a labeling module making it possible to associate with the data flow produced by the reception chain upon detection of the reference signal, the true DoA estimated by the DoA estimator; and a training database suitable for storing the labeled samples output from the labeling module as training data to properly set up the DoA measurement module;
- the mobile platform is a drone
- the transmitter location system operates in the radiofrequency domain
- the subject of the invention is also a system for locating transmitters capable of cooperating with a mobile platform to constitute an assembly in accordance with the previous assembly.
- the transmitter locator system uses the transmitter locator system to measure the DoA of any incident signal.
- FIG. 1 is a schematic representation of an assembly comprising a transmitter location system and a mobile platform according to a preferred embodiment of the invention
- FIG. 2 is a representation in the form of blocks of a preferred embodiment of a method for estimating the direction of arrival - DoA of an electromagnetic signal of interest using the assembly shown in FIG. 1 .
- a transmitter location system implements a machine learning algorithm, preferably of the network type. artificial neurons - RNA. This makes it possible to relax the constraints design techniques related to the complex issue of correcting calibration biases for DoA measurement. Indeed, an automatic learning algorithm, once suitably configured by means of training data, allows automatic correction of imperfections affecting the measurements made by the transmitter location system.
- the antennas are non-linearly spaced so as to be able to resolve ambiguities when the wavelength of the incident signal is short, as is known to those skilled in the art.
- the spatial distribution of the antennas takes place in two dimensions in order to be able to carry out a measurement of DoA in bearing and in elevation.
- a receiver 22 comprises, for example, one or more amplifiers, a demodulator, and a serial digitizer. The different receivers 22 are synchronized on a common clock.
- a receiver 22 which takes the form of an electronic card, performs for example the baseband transposition and the sampling on a 500 MHz band.
- the central frequency is advantageously adjustable between 2 and 18 GHz.
- the data stream at the output of the receivers 22 is for example applied to the input of the computer 25 via an Ethernet link.
- the computer 25 comprises a computing means, such as a processor (for example a multi-core processor or a graphics processor "GPU"), and an information storage means, such as a memory.
- the memory comprises in particular various computer programs, the instructions of which are specific to be executed by the processor.
- the computer 25 comprises a preprocessing module 23 and a module for estimating the DoA 24.
- the preprocessing module 23 which is optional, reduces the size of the data stream at the output of the reception chain 20. It advantageously takes into account certain relevant invariances in the data received, such as for example an invariance in amplitude. , an absolute phase invariance, etc.
- the transmitter location system 12 includes a DoA measurement module 24 capable of providing a measurement of the DoA of an RF signal of interest intercepted in the environment. This measurement is carried out from the time samples delivered by the reception chain 20 (possibly after preprocessing by the module 23) in an estimation time window.
- the DoA 24 measurement module implements a "machine learning" algorithm to perform the direction of arrival measurement - DoA.
- This algorithm which will be described in detail below, requires a learning phase, making it possible to determine the optimal values of the parameters of the module 24.
- training database comprising training data, training data associating the time samples of an incident signal with the true direction of arrival of this incident signal.
- a mobile platform is used allowing to move at convenience a transmitter of reference signals coupled to a light source allowing an estimation of the true DoA of the reference signals emitted by the transmitter and detected by the transmitter tracking system 12.
- the mobile platform is a rotary wing drone 14 on which is embarked:
- an RF transmitter 52 suitable for transmitting reference RF signals, advantageously with different waveforms (in particular at different frequencies), so as to be representative of the RF signals encountered in actual conditions of use of the system 12 ;
- an omnidirectional light source 51 such as for example a set of infrared LEDs.
- the system 12 comprises a measuring device, for example consisting of a camera 31, which is arranged in the vicinity of the antennas 21 of the system 12.
- the camera 31, preferably wide angle, has a sensitivity adapted to the frequency band of the light signal emitted by the light source 51.
- the camera 31 operates in the infrared range.
- the images delivered by the camera are applied to the input of the computer 25, which comprises, among the various programs that it is capable of executing, a DoA estimation module 32 suitable for delivering an estimate of the DoA of the light signal to from the images delivered by the camera 31 and consequently an estimate of the true DoA of the reference RF signal.
- the module 32 implements a simple image processing algorithm, making it possible to extract the position of a bright point corresponding to the light source, and making it possible to convert this position into a relative position measurement with respect to the system 12, for example a position in two dimensions, typically in bearing and elevation relative to a reference direction associated with the antennas 21.
- the system 12 comprises, among the different programs that the computer 25 executes, a labeling module 34 making it possible to associate with the time samples delivered by the reception chain 20 when receiving a reference RF signal, the true DoA measured by module 32 at the same time.
- the system 12 includes a training database 40 suitable for storing the labeled samples delivered at the output of the module 34, as training data.
- the artificial neural network implemented by the DoA 24 measurement module is advantageously of the MLP (“Multi Layer Perceptron”) type.
- MLP Multi Layer Perceptron
- This very simple architecture has a single hidden layer. According to the simulations which have been carried out, thanks to the simplicity of this architecture, good performance is obtained with very reasonable calculation times, both for the learning phase and for the use phase of the system 12.
- the different layers are completely interconnected.
- the DoA measurement module therefore advantageously takes as input the phase shifts between the antennas 21 calculated by the module 23.
- the structure of the input data is as follows: with i the index of the antenna (integer between 1 and the total number of antennas) and j the index of the time sample (integer between 0 and M-1, where McDG is the width of the time window considered for the measurement of the DoA and AT the temporal resolution of the sampling), f is the phase, and the index 1 corresponding to the real part of the complex signal S r and the index 2 corresponds to the imaginary part of the complex signal S '.
- this matrix structure of the input data is "flattened” and transformed into a vector.
- the RNA algorithm performs a classification.
- a class then corresponds to an interval of values of DoA (for example intervals of width of 1 ° in bearing).
- the output layer comprises a non-linear operation of the “softmax” type.
- the size of the output layer corresponds to the number of classes chosen.
- the output vector then corresponds to a probability distribution of the DoA over the angular range considered.
- cross-entropy The criterion to be optimized in the learning phase will be cross-entropy ("cross-entropy").
- the RNA algorithm performs a regression.
- the output is a scalar corresponding to the value of the DoA. This value of DoA can be normalized between 0 and 1.
- the output layer then preferably comprises a non-linear operation of the sigmoid type.
- the criterion to be optimized in the learning phase will then be the mean square error between the ground truth (true DoA) and the prediction (measured DoA).
- the assembly 10 allows the implementation of the DoA 100 measurement method of Figure 2.
- the method 100 begins with a learning phase making it possible to optimize the values of the RNA parameters of the DoA 24 measurement module.
- a step 105 the drone 14 is moved as desired around the antenna assembly of the system 12, making it possible to explore a wide angular range in elevation and bearing.
- This angular sweep can be programmed in advance and automated thanks to the autopilot on board the flight controller of the drone.
- the emission by the transmitter 52 of one or more reference RF signals (with advantageously different shapes) and by the light source 51 of an infrared signal is simultaneously controlled (step 110). .
- step 130 the antennas 21 of the transmitter location system 12 receive the reference RF signal.
- the phases delivered at the output of the preprocessing module 23 are transmitted to the labeling module 34.
- step 140 the labeling module 34 is executed to associate with the phases received from the preprocessing module 23, the true DoA received from the module 32.
- the labeled phases are stored in the training database 40.
- Steps 105 to 140 are iterated (loop 145) for different relative positions of the drone 14 with respect to the transmitter location system 12 so as to populate the learning database 40. It is necessary to have a number sufficient training data to properly sample the desired field of use.
- the method 100 proceeds to the training step 150 proper, in which the parameters of the RNA are optimized from the training data of the database 40.
- the phases of training data are applied at the input of the DoA measurement module 24, and the DoA measurement delivered at the output of the module 24 is compared with the true DoA training data.
- the difference between the measured DoA and the true DoA allows adjustment of the ANR parameters of the DoA 24 measurement module, using an optimization algorithm.
- the transmitter and the drone are turned off and the transmitter locator system 12 can be used (step 160) to measure the DoAs of any incident signals.
- An incident signal from an enemy transmitter arrives on antennas 21 and is digitized.
- the phases obtained feed the artificial neural network of module 24, now suitably configured, which then delivers a measurement of the direction of arrival of the incident signal.
- Tests on the complete assembly were carried out outdoors.
- the root mean square error of the DoA measurement on the test data was 2 °.
- the carrier frequency of the wave was 1 GHz.
- the light source and the camera operate in the visible spectrum.
- the camera is then advantageously provided with an optical bandpass filter for selecting the light signal emitted by the source on board the mobile platform.
- the architecture of the transmitter location system according to the invention incorporates a parametric component which makes it possible to automatically calibrate the antenna, microwave components, the electromagnetic environment, etc. and this without going through long and expensive measurements in an anechoic chamber to carry out the calibration steps as is the case for the state of the art.
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Position Fixing By Use Of Radio Waves (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR1914146A FR3104733B1 (fr) | 2019-12-11 | 2019-12-11 | Ensemble comportant un systeme de localisation d'emetteurs et une plateforme mobile ; systeme de localisation d'emetteurs, plateforme mobile et procede de mesure de direction d'arrivee associes |
PCT/EP2020/085583 WO2021116312A1 (fr) | 2019-12-11 | 2020-12-10 | Ensemble comportant un système de localisation d'émetteurs et une plateforme mobile; système de localisation d'émetteurs, plateforme mobile et procédé de mesure de direction d'arrivée associés |
Publications (1)
Publication Number | Publication Date |
---|---|
EP4073533A1 true EP4073533A1 (fr) | 2022-10-19 |
Family
ID=70456855
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP20820438.8A Withdrawn EP4073533A1 (fr) | 2019-12-11 | 2020-12-10 | Ensemble comportant un système de localisation d'émetteurs et une plateforme mobile; système de localisation d'émetteurs, plateforme mobile et procédé de mesure de direction d'arrivée associés |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP4073533A1 (fr) |
FR (1) | FR3104733B1 (fr) |
WO (1) | WO2021116312A1 (fr) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113534132B (zh) * | 2021-07-16 | 2023-02-10 | 西安电子科技大学 | 一种自适应无人机波达方向估计方法 |
CN113970718A (zh) * | 2021-10-27 | 2022-01-25 | 东南大学 | 一种阵列超分辨波达方向估计方法 |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5768477A (en) * | 1996-09-10 | 1998-06-16 | Southwest Research Institute | Radio direction finding system for narrowband multiple signals |
US10529241B2 (en) * | 2017-01-23 | 2020-01-07 | Digital Global Systems, Inc. | Unmanned vehicle recognition and threat management |
WO2019195327A1 (fr) * | 2018-04-05 | 2019-10-10 | Google Llc | Système radar faisant appel à un dispositif intelligent réalisant une estimation angulaire au moyen d'un apprentissage automatique |
-
2019
- 2019-12-11 FR FR1914146A patent/FR3104733B1/fr active Active
-
2020
- 2020-12-10 WO PCT/EP2020/085583 patent/WO2021116312A1/fr unknown
- 2020-12-10 EP EP20820438.8A patent/EP4073533A1/fr not_active Withdrawn
Also Published As
Publication number | Publication date |
---|---|
FR3104733A1 (fr) | 2021-06-18 |
FR3104733B1 (fr) | 2022-03-18 |
WO2021116312A1 (fr) | 2021-06-17 |
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