EP2649465A1

EP2649465A1 - Device for detecting events

Info

Publication number: EP2649465A1
Application number: EP11794480.1A
Authority: EP
Inventors: Thierry Guignard; Sébastien LESTIEUX
Original assignee: Thales SA
Current assignee: Thales SA
Priority date: 2010-12-10
Filing date: 2011-12-09
Publication date: 2013-10-16
Also published as: US20140321243A1; AU2011340433B2; US9057777B2; WO2012076711A1; FR2968793B1; FR2968793A1; AU2011340433A1

Abstract

The invention relates to a multi-sensor device for detecting events, comprising: first acquisition means (101) including at least one first sensor and operating in a first frequency band, and second acquisition means (102) including at least one second sensor and operating in a second frequency band other than the first frequency band; a means (103) for processing raw data coming from the acquisition means (101, 102), and comprising means (103.1) for detecting events in the raw data and for determining the geographic location (103.2) of said events; a means (104) for transmitting an alert if an event is detected by the processing means, characterized in that said device further comprises a means for storing the raw data, said storage means being capable of restoring the stored raw data in a synchronized manner, and a monitoring means, which, following the detection of an event in the raw data of said acquisition means, enables said processing means to be adapted to detect events in said stored raw data from said other acquisition means.

Description

Device for the detection of events

The invention relates to multi-sensor detection and direction-finding systems, capable of detecting electromagnetic, sound or light radiation and more particularly their integration on mobile platforms.

Systems for detecting electromagnetic, sound or light radiation comprising a plurality of independent sensors are already known. The integration of such systems on mobile platforms requires managing a large number of mechanical, electrical or software type interfaces.

Each of the radiations of interest requires a dedicated sensor to perform detection: a camera for light radiation, microphones for sound radiation or antennas for electromagnetic radiation. The use of independent sensors implies a penalizing volume and weight as part of an integration on a mobile platform such as a vehicle. All these independent sensors also increase the overall cost of the platform.

The diversity of systems makes it particularly difficult to integrate on the same vehicle various products, either for lack of space or for compatibility problems.

The use of independent sensors makes it necessary to merge the information from integrated information (synthesis) delivered from the sensors. This bottom-up approach does not allow the extraction algorithms of each sensor to interact with each other and possibly modify their behavior as a function of the activity present.

The present invention aims in particular to remedy these problems by proposing an event detection device incorporating within the same device all of these sensors and facilitating its integration on a mobile platform.

For this purpose, the subject of the invention is a multi-sensor device for the detection of events comprising

first acquisition means comprising at least a first sensor operating in a first frequency band and second acquisition means comprising at least a second sensor, operating in a second frequency band different from the first frequency band,

means for processing raw data from the acquisition means, and comprising means for detecting events in the raw data and for determining the geographical location of said events,

means for issuing an alert if an event is detected by the processing means

characterized in that it furthermore comprises means for storing the raw data, said storage means being able to restore the stored raw data in a synchronized manner and supervisory means allowing, following the detection of an event in the data raw of one of said acquisition means, adapting said processing means for the detection of events in said stored raw data from said other acquisition means.

The invention has the advantage of simplifying the implementation of a system integrating sensors operating on different frequency bands. The invention allows a high frequency coverage with a single detection device. The prior art uses independent sensors. It is therefore not possible to rationalize the elementary building blocks of the system, each brick being developed independently for each of the systems. The invention makes it possible to use a single processing unit common to all the sensors as well as elements complementary to the device: orientation of the sensor (compass), positioning (GPS) and especially synchronization between sensors (time reference). The invention thus greatly reduces the costs of integration of a multi-sensor system on a platform.

According to one characteristic of the invention, said processing means comprise improved detection means adapted to increase the number of buffer zones for temporary storage of samples of said stored raw data. This makes it possible to be more sensitive and thus to make detection more efficient and more reliable (better protection against false detection) and to keep a good temporal accuracy for the dating of events and this is achievable for example by increasing the number of zones buffer (buffer in English) used for the realization of different treatments.

According to a characteristic of the invention, said supervision means are adapted from the detection of an event in a time interval, to parameterize said processing means in order to carry out the detection from the raw data stored from said other means of acquisition in said same time interval.

This technical characteristic makes it possible to reduce the detection time by focusing the algorithm on the time interval where an event has already been detected.

According to one characteristic of the invention, the multi-sensor detection device further comprises means for determining an orientation of said device, said orientation being transmitted to the processing means.

According to another characteristic of the invention, the multi-sensor detection device further comprises means for determining a common time reference to the sensors.

The invention has the advantage of pooling different resources for each acquisition means. By way of example, mention may be made of: the power supply, the processing means, the means for orientation (including in particular a compass or a GPS) and the means for determining a time reference.

According to one characteristic of the invention, the means for the processing further comprise means for correlating the raw data from the acquisition means.

The use of heterogeneous data fusion methods from different sensors can reduce false event detection alarm rates. The cross-checking of the information provided by the various sensors makes it possible to check their coherence. According to the prior art, no fusion of the data produced by each sensor is performed; and, in the case where a merger is performed, it is performed at a higher level from synthesis data produced by the different sensors.

According to an alternative embodiment of the invention, the sensor of one of the at least two acquisition means is a camera.

According to another embodiment of the invention, which the sensor of one of the at least two acquisition means is a seismic detector.

Advantageously, one of the at least two acquisition means is an array comprising a plurality of sensors configured for a goniometric detection.

Advantageously, the sensors are microphones.

Advantageously, the sensors are antennas.

In one embodiment of the invention, the multi-sensor device for the detection of events further comprises means for activating and deactivating the acquisition means, said acquisition means being able to be activated if an event is detected. The invention will be better understood and other advantages will appear on reading the detailed description given by way of non-limiting example and with the aid of the figures among which:

FIG. 1 represents a first example of the device according to the invention.

FIG. 2 represents a second example of implementation of a device according to the invention.

Figure 3 shows frequency bands of interest for use of a detection device.

FIG. 4 shows an exemplary embodiment of a detection device according to the invention.

The invention relates to a multi-sensor device for the detection of events. Such a device can be easily mounted on a mobile vehicle. It is useful in a civilian or military setting. In the military context, the events to be detected are the actions of an adversary for example a rocket fire or telephone communications between attackers.

The device comprises at least two acquisition means 101, 102 operating in different frequency bands. By different, we mean that can overlap in part or not at all.

In the example presented hereinafter (FIG. 2), the frequency bands in which the different acquisition means 101, 102 (camera, antennas and microphone) operate do not overlap.

Figure 3 shows frequency bands of interest for use of a detection device. :

- frequencies greater than 10 ¹⁵ Hz: visible and ultraviolet spectrum,

frequencies from 10 ¹² Hz to 10 ¹⁵ Hz: infrared,

frequencies from 10 ¹⁰ Hz to 10 ¹² : microwaves,

frequencies from 10 ⁷ Hz to 10 ¹⁰ : radio frequencies,

frequencies below 10 ⁷ : mechanical (resonance / vibration).

The sensors are directly integrated into the device. The data, from the sensors and transmitted to the processing means 103, are raw data, that is to say elementary data that have not undergone prior processing (for example filtering).

The processing means 103 comprise means for the detection 103.1 of events in the raw data. The detection makes it possible to identify a particular "motif" in the data, for example, a telephone communication in the data coming from the antennas or a blast of a shot in the data coming from the microphones.

The device comprises means for the emission 104 of an alert if an event is detected by the processing means. This alert can be visual or audible.

According to one characteristic of the invention, the multi-sensor device for event detection further comprises means 105 for determining an orientation of said device. This orientation is transmitted to the processing means 103. The means 105 for determining an orientation may comprise, for example, a GPS type satellite receiver providing position information and / or a compass indicating a heading. According to another characteristic of the invention, the multi-sensor detection device further comprises means 107 for determining a time reference common to the acquisition means 101, 102. This characteristic is achievable thanks to the integration of the sensors within the device. Thanks to it, all the sensors share a common temporal reference. This feature makes it possible in particular to avoid, during the correlation of the raw data, prior steps of data synchronization. These synchronization steps are necessary with the use of independent sensors (not integrated with the detection device).

The correlation or fusion is provided from raw data, in other words, elementary data from each sensor. In addition, all raw data is sent to the detection algorithms to increase the probability of detection and to reduce the risk of false alarms.

FIG. 2 represents a second exemplary implementation, for example in a military setting for so-called multi-band direction finding, of a device according to the invention. The device comprises three different acquisition means 201, 202, 203.

The sensor of the first acquisition means is a camera 203 for detection in the visible frequency spectrum used, for example, to detect the flash of a firearm when fired.

The second 202 and third 201 acquisition means are sensor networks. The sensors of the second acquisition means are microphones for identifying and locating a rocket fire, for example. The sensors of the third 201 acquisition means are antennas for detecting the emission of a radio wave during an opponent's communication by cell phone or PMR (for Private Mobile Radio).

On such a device, each of the sensor networks is installed so as to minimize the nuisance between the sensors. The networks generally comprise at least three sensors to perform the function of direction finding. The processing means comprise means for determining the geographical location of said events, which in particular make it possible to process the raw data from the sensor networks to determine geographic coordinates of the source at the origin of the event (a telephone or a telephone). radio in the case of a communication, a weapon in the case of a shot).

The means for the location 103.3 of an event are provided within the same processing unit 103 but implement different algorithms for each of the sensor networks, for example, (i) the location of a light flash in a a video sequence from a camera to locate the origin of a shot or (ii) a direction-finding treatment applied to data from a microphone array to determine the origin of a shot.

Figure 4 shows an example embodiment of a detection device. This device comprises three sensors i, j and k. Each of the sensors delivers a raw data stream. Each of these raw data streams is directed to detection means 401 .i, 401 .j, 401 .k and then to means for merging data 402. In this embodiment of the invention, the detection device it furthermore includes a delay line function (LAR) on each raw data stream of each sensor, this makes it possible to store the raw data in order to be able to consult them synchronously later.

The storage means (or delay lines) make it possible to replay a mission after it has been completed.

Following a detection result of an algorithm on a given sensor, for example the sensor i, a supervision module 403 of the detections controls an improved detection (404.i, 404J, 404.k). This improved detection uses the detection algorithms on all the sensors (in the example the sensors i, j and k) on a time window reduced in the past, this via the raw data streams present in the delay lines ( LAR). The integration parameters used to analyze the activity in the past are then improved with an integration (on time signals and / or on the spectra) more important. For example, in the case where the sensor i is a direction-finding sensor working from radio frequency signals, the detection algorithm 401. i can use as input 4 buffers of samples (respecting the Shannon theorem as a function of the size of the fast fourier transform (FFT) that will be performed according to the desired analysis band). Time integration is performed on 2 pairs of time buffers. Then two FFTs are made. Then a spectral integration of the 2 FFTs is realized. For the enhanced detection algorithm 404.i in order to improve the sensitivity performance and to limit the false detections, the number of sample buffers will increase, compared to the detection algorithm 404.i. This is to achieve a larger number of FFTs and then be able to integrate on a larger number of FFTs. It is for example possible to make an integration on 16 FFT, the FFTs themselves using as input an integration of 4 buffers of temporal samples.

This makes it possible to be more sensitive and thus to make detection more efficient and more reliable (better protection against false detection) and to keep a good temporal accuracy for the dating of events.

The width of the time window and its delay in time is to be determined as a function of the relative time differences of propagation of the signals of the different sensors and the average duration of the signals.

This is useful to understand the strategy of the opponent for example: a first telephone call, followed by a shot, followed by a second telephone call.

Claims

1. Multi-sensor device for event detection comprising

first acquisition means (101) comprising at least a first sensor, operating in a first frequency band and second acquisition means (102) comprising at least a second sensor, operating in a second frequency band different from the first frequency band,

means for the processing (103) of raw data from the acquisition means (101, 102), and comprising means for the detection (103.1) of events in the data, and for the determination of the location (103.2 ) the geographical location of the said events,

means for the emission (104) of an alert if an event is detected by the processing means

characterized in that it further comprises:

means for storing the raw data, said storage means being able to restore the raw data stored in synchronized manner and

- Supervisory means (403) allowing, following the detection of an event in the raw data of one of said acquisition means, to set said processing means for the use of said raw data stored from said other means d 'acquisition.

A multi-sensor device for event detection according to claim 1 wherein said processing means (103) comprises improved detection means (401) adapted to increase the number of temporary storage buffer zones of samples said raw data stored.

A multi-sensor device for event detection according to claim 1 or 2 wherein said supervisory means (403) is adapted from the detection of an event in the raw data of one of said plurality of means. acquisition during a time interval, for parameterizing said processing means (103) for the use of said stored raw data from said other acquisition means during said time interval.

4. Multi-sensor device for the detection of events according to one of the preceding claims, further comprising means

(105) for determining an orientation of said device, said orientation being transmitted to the processing means (103).

5. multi-sensor device for the detection of events according to one of the preceding claims further comprising means for the determination (107) of a time reference common to the acquisition means (101, 102).

6. multi-sensor device for the detection of events according to one of the preceding claims, wherein, the means for the processing (103) further comprise means for the correlation (103.3) raw data from the means acquisition (101, 102).

7. multi-sensor device for the detection of events according to one of the preceding claims, wherein the sensor of one of the at least two acquisition means (101, 102) is a camera (203).

8. Multi-sensor device for the detection of events according to one of the preceding claims, wherein the sensor of one of the at least two acquisition means (101, 102) is a seismic detector.

Multi-sensor device for the detection of events according to one of the preceding claims, characterized in that one of the at least two acquisition means (101, 102) is an array comprising a plurality of sensors configured to a goniometric detection.

The multi-sensor device for event detection according to claim 9, wherein the sensors are microphones (202).

1 1. The multi-sensor device for event detection according to claim 9, wherein the sensors are antennas (201).

12. Multi-sensor device for the detection of events according to one of the preceding claims, further comprising means for activating and deactivating the acquisition means, said acquisition means (101, 102) being able to be activated. if an event is detected.