MONITORING

Technical Field

The present disclosure relates to radar systems, for example a radar system that is operable to emit and receive electromagnetic radiation at a frequency in a range of 50 GHz to 100 GHz, and more optionally at a frequency of substantially 77 GHz, for interrogating a spatial region. Moreover, the present disclosure concerns methods of operating aforesaid radar systems. Furthermore, the present disclosure is concerned with computer program products comprising a non-transitory computer-readable storage medium having computer-readable instructions stored thereon, the computer-readable instructions being executable by a computerized device comprising processing hardware to execute aforesaid methods. Furthermore, the present disclosure provides radar calibration targets for calibrating and/or verifying operation of the aforementioned radar systems when in operation.

Background

In overview, radar systems are well known in the art. Typically, a radar system includes an emitting arrangement for emitting electromagnetic radiation towards a region of interest (ROI) and a receiving arrangement for receiving a portion of the emitted electromagnetic radiation that is reflected back from the region of interest (ROI). On account of the emitting arrangement and/or the receiving arrangement having polar characteristics having directions of greater gain, the radar system is capable of mapping out the region of interest (ROI). Moreover, time-of-flight and Doppler frequency shift information included in the portion of the emitted electromagnetic radiation that is reflected back from the region of interest (ROI) enables one or more objects in the region of interest (ROI) to be monitored, for example as in Doppler radar systems for selectively measuring speeds of road vehicles.

In a European patent application EP 2394882 A1 , "Scanner with Secured Function" (inventor: Heinrich Laumen; applicant: Scheldt & Bachmann GmbH), there is described a method of monitoring a functionality of a scanner system, for example, such as a radar scanner system and a laser scanner system, that is used for inspection of security-relevant areas, for example, such as level crossings. Gates are positioned in scanning regions at defined positions and detected by radar scanners. The method includes detecting and evaluating scanning signals of the scanning regions in a scanning process, wherein evaluation of the scanning process, shows whether or not the gates are detected at the defined positions. Accordingly, the scanning regions are adjusted.

In a Japanese patent JP 2006007940 (A), "Calibration Method of Radar Device, Radar Device, Monitoring System, and Program" (inventors: Satoshi Ishii, Yoshikazu Doi, Hiroyuki Hachitsuka, Tetsuo Seki, Masayoshi Moriya and Kazusuke Hamada; applicant: Fujitsu Ltd.), there is described a method of calibrating radar devices that are used to monitor a railroad crossing, whereat a railroad and a road intersect. When installing the radar devices, the position of the railroad is recognized by actually measuring a moving trajectory of trains traveling on the railroad using the radar devices. During calibration of a given radar device, a conversion matrix is generated to convert measurement data of an obstacle measured in a local coordinate system of the given radar device into a traffic road coordinate system of a side of the railroad. The calibration is performed autonomously at individual radar devices without requiring placement of a target reflector for calibration in the rail road crossing, and without increasing man-hours or time required in the calibration even if the number of installations of the radar devices is increased.

In a United States patent US 7, 969, 349 B2," System and Method for Suppressing Close Clutter in a Radar System" (inventors: Timothy R. Holzheimer and Vernon R. Goodman; applicant: Raytheon Company, USA), there is described a system for processing electromagnetic waves in a radar system; the radar system is, for example, mounted upon a road vehicle when in operation. The system includes a transmitter that is operable to transmit operating waves and calibration waves. Moreover, the system includes one or more receivers that are operable to receive reflected calibration waves and operating waves. Furthermore, the system includes a system controller that is operable to process the received calibration waves and operating waves. Optionally, the system controller processes the received waves by generating a threshold signal based upon the calibration waves, and comparing the threshold signal to the operating waves. Moreover, optionally, the system controller also processes the operating waves and the calibration waves in accordance with one or more signal conditioning algorithms. Furthermore, optionally, the system controller displays an image representing a target on a display by comparing the received operating waves with the generated threshold signal.

In a United States patent application US 2005/0128136 A1 , "System and Method for Radar Detection and Calibration" (inventors: Peter S. Wittenberg and John Hayn), there is described a system and method for radar detection and calibration. By measuring a true range of a calibration target on entry to a radar system's detection zone, an actual detection capability of the radar system in given atmospheric conditions can be determined. The radar system is also described as being adapted to determine a sensed position at a sensed time of a target in the radar system's detection zone. A calibration target, for example an unmanned air vehicle (UAV), includes a position device for determining an actual spatial position of the calibration target. A calibration device communicates with the radar system and the calibration target and receives the sensed and actual positions of the calibration target. The calibration device calculates an error between the sensed position and the actual position and adjusts the radar system to reduce, for example to minimize, the error. The calibration target optionally includes a signal augmentation device to augment an associated radar cross-section of the calibration target to replicate radar cross- sections of targets of various types. In such a manner, a true detection range of the radar system is determined for various types of targets under the given current atmospheric conditions.

In a European patent application EP 2722250 A1 , "System and method for object detection" (inventors: Alessandro Agostini, Andrea Ricci and Marco Tili), there is described a system and a method for detecting an object at a railway crossing. The system comprises radar transmitters for scanning a surveillance zone, a passive target for use in determining alignment of a scanning zone of each radar transmitter, and a control unit for use in evaluating the energy signals received by the radar receivers. Moreover, the method comprises activating the radar transmitters, determining alignment of the scanning zone of each radar transmitter with a passive target and scanning a surveillance zone for an object upon positive determination of alignment.

In a United States patent application US 2012/0001767 A1 , "Warning horn control system, radar system, and method' (inventors: Forrest H. Ballinger), there is described a radar system. The radar system includes an emitter system and a reflection target placed opposite to the emitter system to define an area of interest. The radar system also includes a controller configured to identify a reflection from the reflection target, and to stop sending a radar check signal if the reflection is not identified. The radar system may be a part of a warning horn control system, where the radar check signal is used as a control input for activating a warning horn.

In a United States patent application US 2006/0028356 A1 , "Microwave detection system and method for detecting intrusion to an off-limits zone" (inventors: Moreno Pieralli), there is described a system and method for automatically detecting intrusion in an off-limits zone. The system includes a transmitter for transmitting a signal along a path likely to encounter an intruder, and a modulating reflector for receiving the transmitted signal. The system further includes a processor coupled to the transmitter and the receiver.

In a German patent application DE 29623877 U1, " Risk space monitoring" (applicant: Honeywell AG), there is described an arrangement for monitoring an area of danger including a rotating radar range sensor for horizontal scanning at edge of the area of danger, reference markers on boundary of the area of danger, and a computer connected to the rotating radar range sensor. The computer contains data based on distance and angle of the reference markers, and sector wise reference data of scanned area. In a United States patent application US 2007/0040070 A1 , "Railroad crossing surveillance and detection system" (inventors: Bob Stevenson, Paul Calixto), there is described a railroad remote monitoring and detection system employing cameras, wherein the cameras are optionally remotely positionable and repositionable, and other motion and presence detection devices such as millimeter wave radar and/or passive infrared and or ultrasound detectors. The system uses multiple sensor devices to reduce an occurrence of false alarms. The system employs software and logic circuits to detect predetermined alarm conditions and then send a signal to a local or central command centre (US English: "center") and trains on the route. The system includes wireless receivers onboard the train that scan for monitoring information from one or more monitor stations in advance of the trains progressing, namely for giving the train engineer/ driver advanced warning of hazardous conditions on the train's route. A technical problem that is often faced in conventional radar systems is how to guarantee correct operation of a radar system in a safety-critical situation, where various factors can influence performance of the radar system. Examples of such factors include:

(i) vandalism, for example rotating a radar antenna to face away from a region of interest (ROI);

(ii) failure of radar parts, lack of calibration, and/or unexpected occluding objects placed near or over a radar antenna arrangement;

(iii) changing environmental circumstances, for example long-term growth of vegetation (for example, trees), snow, and ice;

(iv) system failure, for example, such as a railway barrier being down permanently, and a vehicle immobilized across rails at level-crossing in dark conditions where street illumination has failed; and

(v) spurious interference from other sources of radar radiation, for example from vehicle-mounted automatic radar braking systems and vehicle-mounted automatic radar steering systems.

Guaranteeing correct operation of a radar system in a safety-critical situation represents a technical problem that the present disclosure seeks to address. Sum mary

The present disclosure seeks to provide an improved radar system that is more reliable in its operation of monitoring a region of interest (ROI).

Moreover, the present disclosure seeks to provide an improved method of monitoring a region of interest (ROI) in a more reliable manner using a radar system.

Furthermore, the present disclosure seeks to provide an improved target for use in verifying operation and integrity of the aforementioned improved radar system.

According to a first aspect, there is provided a radar system for monitoring a region of interest (ROI), wherein the radar system includes an antenna arrangement for emitting and receiving electromagnetic radar radiation and a signal processing arrangement for generating signals to be emitted in operation as corresponding electromagnetic radar radiation from the antenna arrangement to the region of interest (ROI) and also for processing received signals resulting from reflections of the electromagnetic radar radiation from one or more objects present in the region of interest (ROI), characterized in that:

(i) the radar system is arranged such that at least one of the one or more objects present in the region of interest (ROI) includes a radar radiation reflecting target;

(ii) the signal processing arrangement is operable to determine a component of the received signals corresponding to the radar radiation reflecting target, and to monitor over a period of time changes in the component of the received signals, wherein changes in the component greater than at least one threshold value are indicative of a malfunction of the radar system and/or a change in a status of the region of interest (ROI) that is potentially hazardous;

(iii) the radar system is operable to compare additional sensor signals, wherein the additional sensor signals are other than the received signals resulting from reflections of the electromagnetic radar radiation from one or more objects present in the region of interest (ROI), against one or more associated threshold values to determine whether or not a malfunction or hazardous situation has arisen, and to fuse the additional sensor signals with an indication of the malfunction or hazardous situation as generated by the component of the received signals; and

(iv) the radar system is arranged to employ cued search capabilities for processing the received signals corresponding to the radar radiation reflecting target and the additional sensor signals.

The present invention is of advantage in that changes in the component of the received signals corresponding to the planar radar radiation reflecting target enable the radar system to identify malfunction in its operation and/or potentially hazardous situations in a more reliable manner.

Optionally, in the radar system, the radar radiation reflecting target is implemented to include one or more planar surfaces and is fabricated from a sheet or mesh of a conducting material whose one or more planar surfaces are substantially orthogonal in operation to aground surface in the region of interest (ROI). Optionally, the radar radiation reflecting target also serves to function as an advertising or visual information bill board.

Optionally, in the radar system, the radar radiation reflecting target comprises a polyhedral structure, whose radar cross section versus angle of incidence is known to the radar system. More optionally, the polyhedral structure is trihedral. Optionally, the radar system is operable to generate the electromagnetic radar radiation in a frequency range of 10 GHz to 200 GHz. More optionally, the radar system is operable to generate the electromagnetic radar radiation in a frequency range of 15 GHz to 150 GHz. Yet more optionally, the radar system is operable to generate the electromagnetic radar radiation at a frequency of substantially 77 GHz. Alternatively, optionally, the radar system is operable to generate the electromagnetic radar radiation at a frequency in a range of 15 GHz to 30 GHz. Yet more optionally, the radar system is operable to generate the electromagnetic radar radiation at a frequency of substantially 24 GHz.

Optionally, in the radar system, the additional sensor signals include at least one of: (a) audio signals captured in respect of the region of interest (ROI);

(b) optical signals captured in respect of the region of interest (ROI);

(c) ultrasonic signals captured in respect of the region of interest (ROI); and

(d) sensor signals indicative of an orientation and/or spatial position of the radar radiation reflecting target relative to the antenna arrangement.

Optionally, the radar system is coupled via a data communication network to provide wirelessly a warning of one or more potential obstacles at the region of interest (ROI) to trains approaching the region of interest (ROI), so as to enable the trains to take collision-avoidance actions, wherein the region of interest (ROI) includes a railway level-crossing. More optionally, in this regard, the collision-avoidance actions include at least one of:

(i) applying brakes of a train approaching the railway level-crossing;

(ii) stopping the train in advance of the railway level-crossing; and/or

(iii) slowing down a velocity of the train.

According to a second aspect, there is provided a method of monitoring a region of interest via a radar system, wherein the radar system is operable to monitor a region of interest (ROI), wherein the radar system includes an antenna arrangement for emitting and receiving electromagnetic radar radiation and a signal processing arrangement for generating signals to be emitted in operation as corresponding electromagnetic radar radiation from the antenna arrangement to the region of interest (ROI) and also for processing received signals resulting from reflections of the electromagnetic radar radiation from one or more objects present in the region of interest (ROI), characterized in that the method includes :

(i) arranging the radar system such that at least one of the one or more objects present in the region of interest (ROI) includes a radar radiation reflecting target; (ii) operating the signal processing arrangement to determine a component of the received signals corresponding to the radar radiation reflecting target, and to monitor over a period of time changes in the component of the received signals, wherein changes in the component greater than at least one threshold value are indicative of a malfunction of the radar system and/or a change in a status of the region of interest (ROI) that is potentially hazardous;

(iii) operating the radar system to compare additional sensor signals, wherein the additional sensor signals are other than the received signals resulting from reflections of the electromagnetic radar radiation from one or more objects present in the region of interest (ROI), against one or more associated threshold values to determine whether or not a malfunction or hazardous situation has arisen, and to fuse the additional sensor signals with an indication of the malfunction or hazardous situation as generated by the component of the received signals; and

(iv) arranging for the radar system to employ cued search capabilities for processing the received signals corresponding to the radar radiation reflecting target and the additional sensor signals.

The present invention is of advantage in that the method provides for changes in the component of the received signals corresponding to the planar radar radiation reflecting target to enable the radar system to identify malfunction in its operation and/or potentially hazardous situations in a more reliable manner. Optionally, the method includes implementing the radar radiation reflecting target to include one or more planar surfaces and to be fabricated from a sheet or mesh of a conducting material whose one or more planar surfaces are substantially orthogonal in operation to a ground surface in the region of interest (ROI). Optionally, the method includes implementing the radar radiation reflecting target also to serve to function as an advertising or visual information bill board. Optionally, in the method, the radar radiation reflecting target comprises a polyhedral structure, whose radar cross section versus angle of incidence is known to the radar system. More optionally, in the method, the polyhedral structure is trihedral. Optionally, the method includes operating the radar system to generate the electromagnetic radar radiation in a frequency range of 10 GHz to 200 GHz. More optionally, the method includes operating the radar system to generate the electromagnetic radar radiation in a frequency range of 15 GHz to 150 GHz. Yet more optionally, the method includes operating the radar system to generate the electromagnetic radar radiation at a frequency of substantially 77 GHz. Alternatively, optionally, the method includes operating the radar system to generate the electromagnetic radar radiation at a frequency in a range of 15 GHz to 30 GHz. Yet more optionally, the method includes operating the radar system to generate the electromagnetic radar radiation at a frequency of substantially 24 GHz.

Optionally, in the method, the additional sensor signals include at least one of:

(a) audio signals captured in respect of the region of interest (ROI);

(b) optical signals captured in respect of the region of interest (ROI);

(c) ultrasonic signals captured in respect of the region of interest (ROI); and (d) sensor signals indicative of an orientation and/or spatial position of the radar radiation reflecting target relative to the antenna arrangement.

Optionally, in the method, the radar system is coupled via a data communication network to provide wirelessly a warning of one or more potential obstacles at the region of interest (ROI) to trains approaching the region of interest (ROI), so as to enable the trains to take collision-avoidance actions, wherein the region of interest (ROI) includes a railway level-crossing. More optionally, in the method, the collision- avoidance actions include at least one of:

(i) applying brakes of a train approaching the railway level-crossing;

(ii) stopping the train in advance of the railway level-crossing; and/or

(iii) slowing down a velocity of the train. According to a third aspect, there is provided a radar radiation reflection target for use with the method pursuant to the second aspect.

Optionally, the radar radiation reflection target includes one or more planar surfaces and is fabricated from a sheet or mesh of a conducting material whose one or more planar surfaces are substantially orthogonal in operation to a ground surface in the region of interest (ROI).

Optionally, the radar radiation reflection target is one of: a planar radar radiation reflecting target, a trihedral corner radar radiation reflector, a tubular radar radiation reflecting target, a frusto-conical radar radiation reflecting target, an octahedral radar radiation reflecting target.

Optionally, the method includes implementing the radar radiation reflecting target also to serve to function as an advertising or visual information bill board.

Optionally, the radar radiation reflection target includes a mounting arrangement that is operable to rotate an orientation and/or a spatial position of the radar radiation reflection target in operation in association with a target signal that is indicative and/or controlling the orientation and/or the spatial position of the radar radiation reflection target in operation.

Optionally, the radar radiation reflection target includes a communication arrangement for communicating the target signal to and/or from a radar system.

According to a fourth aspect, there is provided a computer program product comprising a non-transitory computer-readable storage medium having computer- readable instructions stored thereon, the computer-readable instructions being executable by a computerized device comprising processing hardware to execute a method pursuant to the second aspect. Embodiments of the present disclosure substantially eliminate or at least partially address the aforementioned problems in the prior art, without complicating a radar system or adding significantly to its cost. Additional aspects, advantages, features and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative embodiments construed in conjunction with the appended claims that follow.

It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.

Description of diagrams

Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:

FIG. 1 is a schematic illustration of an example network environment that is suitable for practicing embodiments of the present disclosure;

FIG.2 is a schematic illustration of an example implementation of a radar system, in accordance with an embodiment of the present disclosure;

FIGs. 3A and 3B collectively are a schematic illustration of a radar system, in accordance with an embodiment of the present disclosure; and

FIGs. 4A-4D are schematic illustrations of a radar radiation reflecting target for use with the radar system of FIG.2, in accordance with various embodiments of the present disclosure.

In the accompanying diagrams, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non- underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing. Description of embodiments of the invention

According to a first aspect, there is provided a radar system for monitoring a region of interest (ROI), wherein the radar system includes an antenna arrangement for emitting and receiving electromagnetic radar radiation and a signal processing arrangement for generating signals to be emitted in operation as corresponding electromagnetic radar radiation from the antenna arrangement to the region of interest (ROI) and also for processing received signals resulting from reflections of the electromagnetic radar radiation from one or more objects present in the region of interest (ROI), characterized in that:

(i) the radar system is arranged such that at least one of the one or more objects present in the region of interest (ROI) includes a radar radiation reflecting target;

(ii) the signal processing arrangement is operable to determine a component of the received signals corresponding to the radar radiation reflecting target, and to monitor over a period of time changes in the component of the received signals, wherein changes in the component greater than at least one threshold value are indicative of a malfunction of the radar system and/or a change in a status of the region of interest (ROI) that is potentially hazardous;

(iii) the radar system is operable to compare additional sensor signals, wherein the additional sensor signals are other than the received signals resulting from reflections of the electromagnetic radar radiation from one or more objects present in the region of interest (ROI), against one or more associated threshold values to determine whether or not a malfunction or hazardous situation has arisen, and to fuse the additional sensor signals with an indication of the malfunction or hazardous situation as generated by the component of the received signals; and

(iv) the radar system is arranged to employ cued search capabilities for processing the received signals corresponding to the radar radiation reflecting target and the additional sensor signals.

The radar system is of advantage in that changes in the component of the received signals corresponding to the planar radar radiation reflecting target enable the radar system to identify malfunction in its operation and/or potentially hazardous situations in a more reliable manner.

Optionally, in the radar system, the radar radiation reflecting target is implemented to include one or more planar surfaces and is fabricated from a sheet or mesh of a conducting material whose one or more planar surfaces are substantially orthogonal in operation to a ground surface in the region of interest (ROI). Optionally, the radar radiation reflecting target also serves to function as an advertising or visual information bill board. "Substantially orthogonaF for purposes of the radar system lies, for example, in a range of -45° to +45° relative to exact orthogonality, more optionally in a range of -22° to +22° relative to exact orthogonality

Optionally, in the radar system, the radar radiation reflecting target comprises a polyhedral structure, whose radar cross section versus angle of incidence is known to the radar system. More optionally, the polyhedral structure is trihedral.

Optionally, the radar system is operable to generate the electromagnetic radar radiation in a frequency range of 10 GHz to 200 GHz. More optionally, the radar system is operable to generate the electromagnetic radar radiation in a frequency range of 15 GHz to 150 GHz. Yet more optionally, the radar system is operable to generate the electromagnetic radar radiation at a frequency of substantially 77 GHz. Alternatively, optionally, the radar system is operable to generate the electromagnetic radar radiation at a frequency in a range of 15 GHz to 30 GHz. Yet more optionally, the radar system is operable to generate the electromagnetic radar radiation at a frequency of substantially 24 GHz.

Optionally, in the radar system, the additional sensor signals include at least one of:

(a) audio signals captured in respect of the region of interest (ROI);

(b) optical signals captured in respect of the region of interest (ROI);

(c) ultrasonic signals captured in respect of the region of interest (ROI); and

(d) sensor signals indicative of an orientation and/or spatial position of the radar radiation reflecting target relative to the antenna arrangement. Optionally, the radar system is coupled via a data communication network to provide wirelessly a warning of one or more potential obstacles at the region of interest (ROI) to trains approaching the region of interest (ROI), so as to enable the trains to take collision-avoidance actions, wherein the region of interest (ROI) includes a railway level-crossing. More optionally, in this regard, the collision-avoidance actions include at least one of:

(i) applying brakes of a train approaching the railway level-crossing;

(ii) stopping the train in advance of the railway level-crossing; and/or

(iii) slowing down a velocity of the train.

According to a second aspect, there is provided a method of monitoring a region of interest via a radar system, wherein the radar system is operable to monitor a region of interest (ROI), wherein the radar system includes an antenna arrangement for emitting and receiving electromagnetic radar radiation and a signal processing arrangement for generating signals to be emitted in operation as corresponding electromagnetic radar radiation from the antenna arrangement to the region of interest (ROI) and also for processing received signals resulting from reflections of the electromagnetic radar radiation from one or more objects present in the region of interest (ROI), characterized in that the method includes :

(i) arranging the radar system such that at least one of the one or more objects present in the region of interest (ROI) includes a radar radiation reflecting target;

(ii) operating the signal processing arrangement to determine a component of the received signals corresponding to the radar radiation reflecting target, and to monitor over a period of time changes in the component of the received signals, wherein changes in the component greater than at least one threshold value are indicative of a malfunction of the radar system and/or a change in a status of the region of interest (ROI) that is potentially hazardous;

(iii) operating the radar system to compare additional sensor signals, wherein the additional sensor signals are other than the received signals resulting from reflections of the electromagnetic radar radiation from one or more objects present in the region of interest (ROI), against one or more associated threshold values to determine whether or not a malfunction or hazardous situation has arisen, and to fuse the additional sensor signals with an indication of the malfunction or hazardous situation as generated by the component of the received signals; and

arranging for the radar system to employ cued search capabilities for processing the received signals corresponding to the radar radiation reflecting target and the additional sensor signals.

The method provides for changes in the component of the received signals corresponding to the planar radar radiation reflecting target to enable the radar system to identify malfunction in its operation and/or potentially hazardous situations in a more reliable manner. Optionally, the method includes implementing the radar radiation reflecting target to include one or more planar surfaces and to be fabricated from a sheet or mesh of a conducting material whose one or more planar surfaces are substantially orthogonal in operation to a ground surface in the region of interest (ROI). Optionally, the method includes implementing the radar radiation reflecting target also to serve to function as an advertising or visual information bill board.

Optionally, in the method, the radar radiation reflecting target comprises a polyhedral structure, whose radar cross section versus angle of incidence is known to the radar system. More optionally, in the method, the polyhedral structure is trihedral.

Optionally, the method includes operating the radar system to generate the electromagnetic radar radiation in a frequency range of 10 GHz to 200 GHz. More optionally, the method includes operating the radar system to generate the electromagnetic radar radiation in a frequency range of 15 GHz to 150 GHz. Yet more optionally, the method includes operating the radar system to generate the electromagnetic radar radiation at a frequency of substantially 77 GHz. Alternatively, optionally, the method includes operating the radar system to generate the electromagnetic radar radiation at a frequency in a range of 15 GHz to 30 GHz. Yet more optionally, the method includes operating the radar system to generate the electromagnetic radar radiation at a frequency of substantially 24 GHz. Optionally, in the method, the additional sensor signals include at least one of:

(a) audio signals captured in respect of the region of interest (ROI);

(b) optical signals captured in respect of the region of interest (ROI);

(c) ultrasonic signals captured in respect of the region of interest (ROI); and

(d) sensor signals indicative of an orientation and/or spatial position of the radar radiation reflecting target relative to the antenna arrangement.

Optionally, in the method, the radar system is coupled via a data communication network to provide wirelessly a warning of one or more potential obstacles at the region of interest (ROI) to trains approaching the region of interest (ROI), so as to enable the trains to take collision-avoidance actions, wherein the region of interest (ROI) includes a railway level-crossing. More optionally, in the method, the collision- avoidance actions include at least one of:

(i) applying brakes of a train approaching the railway level-crossing;

(ii) stopping the train in advance of the railway level-crossing; and/or

(iii) slowing down a velocity of the train.

According to a third aspect, there is provided a radar radiation reflection target for use with the method pursuant to the second aspect. Optionally, the radar radiation reflection target includes one or more planar surfaces and is fabricated from a sheet or mesh of a conducting material whose one or more planar surfaces are substantially orthogonal in operation to a ground surface in the region of interest (ROI). Optionally, the method includes implementing the radar radiation reflecting target also to serve to function as an advertising or visual information bill board. Optionally, the radar radiation reflection target includes a mounting arrangement that is operable to rotate an orientation and/or a spatial position of the radar radiation reflection target in operation in association with a target signal that is indicative and/or controlling the orientation and/or the spatial position of the radar radiation reflection target in operation.

Optionally, the radar radiation reflection target includes a communication arrangement for communicating the target signal to and/or from a radar system. According to a fourth aspect, there is provided a computer program product comprising a non-transitory computer-readable storage medium having computer- readable instructions stored thereon, the computer-readable instructions being executable by a computerized device comprising processing hardware to execute a method pursuant to the second aspect.

In overview, embodiments of the present disclosure provide a radar system for monitoring a region of interest (ROI) in a more reliable manner, as compared to conventional radar systems. The radar system includes an antenna arrangement for emitting and receiving electromagnetic radar radiation, and a signal processing arrangement for generating signals to drive the antenna arrangement to emit corresponding electromagnetic radar radiation to the region of interest (ROI) and also for processing received signals resulting from reflections of the electromagnetic radar radiation from one or more objects present in the region of interest (ROI). The radar system is arranged such that at least one of the one or more objects present in the region of interest (ROI) includes a radar radiation reflecting target, for example a planar radar radiation reflecting target, for example a radar radiation reflecting target that has one or more planar or gently curved radiation reflecting surfaces provided thereon. However, it will be appreciated that "planar" also includes planar or gently curved radar radiation reflecting surfaces having features, for example one or more projections, indentations or holes, that are capable of providing detectable characterizing reflections of radar radiation. The signal processing arrangement is operable to determine a component of the received signals corresponding to the radar radiation reflecting target, and to monitor over a period of time changes in the component of the received signals. Changes in the component greater than at least one threshold value are indicative of a malfunction of the radar system and/or a change in a status of the region of interest (ROI) that is potentially hazardous. Thus, a technical field of use of the radar system is for monitoring busy safety-critical regions, for example, such as railway level- crossings.

The radiation reflecting target is, for example, a passive target that is mounted in a fixed spatial location and with a fixed angular orientation with respect to the radar system. Alternatively, the radiation reflecting target is, for example, mounted on an actuating arrangement, for example a rotatable turntable, that temporally changes an angular orientation of the radiation reflecting target and/or a spatial position of the radiation reflecting target, for example relative to the radar system. Yet alternatively, the radiation reflecting target is, for example, mounted on an actuating arrangement that is controlled from the radar system, so that the radar system is operable to perform a self-verification that the radar system is functioning correcting and, optionally, also to perform self-calibration, namely auto-calibration. Yet alternatively, the radiation reflecting target is, for example, mounted on an actuating arrangement that provides a target signal to the radar system, wherein the target signal is indicative of a spatial position and/or an orientation of the radiation reflecting target, for example relative to the radar system; in such case, the actuating arrangement includes a controller for moving the radiation reflection target, for example by rotating it, and for providing the target signal to be communicated to the radar system. When the radiation reflecting target is mounted on an actuating arrangement, for example a motorized actuated table, for example provided with power from a solar cell or similar localized source of electrical power, it is beneficially also employed to provide varying advertisement material, for example in a form of a rotating advertising billboard. When vehicles are waiting near a railway level crossing for a train to pass, the rotating advertisement billboard is able to provide advertisement interest to drivers of the vehicles, as well as potentially providing a source of advertisement income. The radiation reflecting target is optionally implemented to be of a polyhedral shape, for example a cube, a trihedron, a decahedron and so forth; however, other implementations of the radiation reflecting target are possible, for example a planar sheet target, a frusto-conical reflector target, a tubular reflector target, a spherical reflector target and so forth. Walls of the radiation reflecting target are optionally fabricated from a conductive metal sheet, a metal mesh, a conductive polymer or similar. Optionally, sides of the radiation reflecting target, when implemented as a polyhedral shape, have mutually different surface conductivities or radar radiation reflecting characteristics for providing the radar system with a pre-determ ined range of radar radiating reflection characteristics; alternatively, the sides of the radar reflecting target include mutually different numbers of holes or dielectric regions that provide distinctive radar radiation properties to each of the sides. However, it will be appreciated that the radiation reflecting target is optionally implemented as a simple sheet or mesh of conductive material (for example, a metal such as Copper, stainless steel, Nickel, Zinc, a metal alloy or similar), a folded sheet fabricated a mesh or plate of metal, a cylinder fabricated from a sheet or a mesh of metal, a frusto-conical cone fabricated from a sheet or a mesh of metal, and similar. Optionally, the radar system is provided with a plurality of radiation reflecting targets; more optionally, two or more of the radiation reflecting targets are mounted on respective actuating arrangements, and, in operation, are rotated at mutually different rates and/or spatially moved in mutually different directions. In such case, the radar system controls operation of the respective actuating arrangements, and/or receives one or more signals indicative of angular orientations and/or spatial positions of the respective actuating arrangements and their corresponding radiation reflecting targets. Use of a plurality of actuated radiation reflecting targets enables algorithms of the radar system to be fine-tuned, namely adapted, to be more selective when identifying various objects present in the region of interest (ROI); optionally the algorithms employ neural-network or artificial-intelligence methods. Artificial- intelligence methods include, for example cognitive branching trees, whose structure is modified by aforementioned auto-calibration of the radar system. Various commercial proprietary neural-network algorithms and artificial-intelligence algorithms are presently available, for example LISP®, and similar. Optionally, the radar system, when using the radar radiation reflecting target for auto-calibrating purposes, is operable to detect longterm gradual changes, for example in a time- scale of weeks or months, in reflection characteristics of the radar radiation reflecting target for providing an error measurement that can be used for auto-calibration. When the changes in reflection characteristics of the radar radiation reflecting target occur temporally too rapidly, for example in matters of hours or a couple of days, namely exceed a rate-of-change threshold, the radar system interprets to be an issue with the radar radiation reflecting target, for example it has become damaged or there is an obscuration, for example ice or snow precipitation on the radar radiation reflecting target. Such threshold detection avoids the radar system mis- calibrating itself, or misinterpreting the radar radiation reflecting target when subject to adverse weather conditions, for example in winter time when ice and snow can form and affect operation of the radar system. FIG. 1 is a schematic illustration of an example network environment 100 that is suitable for practicing embodiments of the present disclosure. The network environment 100 includes at least one radar system, depicted as a radar system 102a, a radar system 102b and a radar system 102c in FIG. 1 (hereinafter collectively referred to as radar systems 102), a server arrangement 104, a database 106 associated with the server arrangement 104, and a data communication network 108.

The network environment 100 can be implemented in various ways, depending on various possible scenarios. In one implementation, the network environment 100 is implemented by way of a spatially collocated arrangement of the server arrangement 104 and the database 106. In another implementation, the network environment 100 is implemented by way of a spatially distributed arrangement of the server arrangement 104 and the database 106 coupled mutually in communication via a data communication network, for example, such as the data communication network 108. In yet another implementation, the server arrangement 104 and the database106 are implemented via cloud-based computing services. The data communication network 108 couples the radar systems 102 to the server arrangement 104, and provides a communication medium between the radar systems 102 and the server arrangement 104 for exchanging data therebetween.

The data communication network 108 can be a collection of individual networks, interconnected with each other and functioning as a single large network. Such individual networks may be wired, wireless, or a combination thereof. Examples of such individual networks include, but are not limited to, Local Area Networks (LANs), Wide Area Networks (WANs), Metropolitan Area Networks (MANs), Wireless LANs (WLANs), Wireless WANs (WWANs), Wireless MANs (WMANs), the Internet, second generation (2G) telecommunication networks, third generation (3G) telecommunication networks, fourth generation (4G) telecommunication networks, satellite-based telecommunication networks, and Worldwide Interoperability for Microwave Access (WiMAX) networks.

The radar systems 102 are installed and arranged to monitor their respective regions of interest (ROI's). Optionally, when a given radar system 102 identifies a situation that is potentially hazardous, for example, such as a malfunction in its operation and/or a change in a status of its region of interest (ROI) that is potentially hazardous, the given radar system 102 sends to the server arrangement 104 information pertaining to the identified situation. Optionally, the server arrangement 104 then sends a notification about the identified situation to a concerned party.

Optionally, in this regard, the server arrangement 104 sends a notification to alert service personnel to perform a required maintenance action. Optionally, the maintenance action includes at least one of:

(i) resolving a malfunction in the operation of the given radar system 102; (ii) rotating an antenna arrangement of the given radar system 102 to face towards its region of interest (ROI);

(iii) removing occluding objects, for example, such as growing vegetation, snow and ice, placed near or over the given radar system 102 and/or its corresponding planar radar radiation reflecting target present in the region of interest (ROI);

(iv) replacing a part of the given radar system 102; and/or

(v) replacing the given radar system 102. Optionally, when the region of interest (ROI) includes a railway level-crossing, the given radar system 102 is coupled via the data communication network 108 to provide wirelessly a warning of one or more potential obstacles at the railway level-crossing to trains approaching the railway level-crossing. This enables the trains to take collision-avoidance actions.

Optionally, in this regard, the collision-avoidance actions include at least one of: applying brakes of a train approaching the railway level-crossing;

topping the train in advance of the railway level-crossing; and/or

slowing down a velocity of the train.

Optionally, the given radar system 102 provides the warning of the one or more potential obstacles at the railway level-crossing to the trains, via the server arrangement 104.

Optionally, the given radar system 102 receives, from the server arrangement 104, train schedule information, for example including information pertaining to trains approaching its region of interest (ROI). Optionally, the given radar system 102 also receives, from the server arrangement 104, software updates for updating a software product employed by a signal processing arrangement of the given radar system 102. FIG. 1 is merely an example, which should not unduly limit the scope of the claims herein. It is to be understood that the specific designation for the network environment 100 is provided as an example and is not to be construed as limiting the network environment 100 to specific numbers, types, or arrangements of radar systems, server arrangements, databases, and data communication networks. A person skilled in the art will recognize many variations, alternatives, and modifications of embodiments of the present disclosure. FIG. 2 is a schematic illustration of an example implementation of a radar system 202, in accordance with an embodiment of the present disclosure. With reference to FIG. 2, the radar system 202 is mounted on a pole, and is arranged to monitor a region of interest (ROI) 204. The region of interest (ROI) 204 includes a railway level-crossing, where a road and a railway track intersect. However, it will be appreciated that the radar system 202 can be mounted on other foundations, for example onto walls of a building and so forth.

In operation, when an antenna arrangement of the radar system 202 emits electromagnetic radar radiation towards the region of interest (ROI) 204, at least a portion of the electromagnetic radar radiation is reflected back to the antenna arrangement from one or more objects present in the region of interest (ROI) 204. Subsequently, a signal processing arrangement of the radar system 202 processes received signals resulting from received reflections of the electromagnetic radar radiation.

The radar system 202 is arranged such that at least one of the one or more objects present in the region of interest (ROI) includes at least one radar radiation reflecting target, for example a plurality of such radar radiation reflecting targets, depicted as a planar radar radiation reflecting target 206 in FIG.2. Correspondingly, the signal processing arrangement of the radar system 202 is operable to determine a component of the received signals corresponding to the at least radar radiation reflecting target 206, and to monitor over a period of time changes in the component of the received signals. Changes in the component greater than at least one threshold value are indicative of a malfunction of the radar system 202 and/or a change in a status of the region of interest (ROI) 204 that is potentially hazardous.

It will be appreciated that, in correct operating conditions, the radar radiation reflecting target 206 reflects a portion of the electromagnetic radar radiation in a predictable manner. Optionally a plurality of radar radiation reflecting targets 206 is employed, as aforementioned.

The component of the received signals corresponding to the radar radiation reflecting target 206, namely signals corresponding to reflections from the radar radiation reflecting target 206, are distinguished from other components of the received signals, namely signals corresponding to reflections from the remainder of the region of interest (ROI), by using at least one of:

(i) a signature encoded onto the electromagnetic radar radiation,

and/or

(ii) a steered sensing directionality, namely digital beam forming, of the radar system 202.

Optionally, the signature encoded onto the electromagnetic radar radiation is a sequence of frequency shifts and/or amplitude shifts. Optionally, in this regard, the signal processing arrangement of the radar system 202 is operable to correlate a delayed signature received at the antenna arrangement of the radar system 202 with a copy of the signature to measure a time-of-flight, namely a distance from the radar system 202 to the railway level-crossing and to the radar radiation reflecting target 206.

Moreover, optionally, the signal processing arrangement of the radar system 202 is operable to render the radar system 202 less prone to interference from, for example, vehicle-mounted radar apparatus that may also be operating at radar radiation frequencies similar to those of the radar system 202. Otherwise, such vehicle-mounted radar apparatus could result in false identification of obstacles, which could result in train delays and associated costs. Furthermore, optionally, the planar radar radiation reflecting target 206, for example planar radiation reflecting target, is implemented as a sheet or mesh of a conducting material whose plane is substantially orthogonal in operation to a ground surface in the region of interest (ROI ) 204. More optionally, the conducting material is a metal or electrically conductive polymer.

Optionally, the radar radiation reflecting target 206 serves to function as an advertising or visual information bill board. Additionally or alternatively, optionally, the radar radiation reflecting target 206 serves to function as a shield from snow deposition onto the railway level-crossing, for example in cold climates.

Optionally, the radar radiation reflecting target 206 comprises a calibrated radar corner reflector of a polyhedral structure, whose radar cross section versus angle of incidence is known to the radar system 202. More optionally, the polyhedral structure is trihedral, octahedral, decahedral and similar.

Optionally, the radar system 202 is operable to compare other sensor signals against one or more associated threshold values to determine whether or not a malfunction or hazardous situation has arisen, and to fuse the other sensor signals with an indication of the malfunction or hazardous situation as generated by the component of the received signals.

Optionally, in this regard, the other sensor signals include at least one of:

(a) audio signals captured in respect of the region of interest (ROI) 204;

(b) optical signals captured in respect of the region of interest (ROI) 204; and/or (c) ultrasonic signals captured in respect of the region of interest (ROI) 204. Optionally, the other sensor signals are captured by sensors that are coupled to the radar system 202. Examples of the sensors include, but are not limited to, audio sensors, optical sensors, angular orientation sensors, position sensor and ultrasonic sensors.

Optionally, at least one of the sensors is included within the radar system 202.

Optionally, the aforementioned sensor fusion is performed by employing a Kalman filter or other suitable filters.

Moreover, optionally, the radar system 202 is arranged such that cued search capabilities are employed in the radar system 202 using at least one of the other sensor signals. In such a case, the radar system 202 is not operated continuously, and is operated only when required. As an example, an audio sensor can be used to switch on/off the radar system 202 in order to relax computational demands and power consumption of the radar system 202.

Moreover, optionally, when one or more potential obstacles are identified in the region of interest (ROI) 204, the radar system 202 is used to switch "on" an optical illumination of the railway level-crossing, which is otherwise switched "off" to conserve energy. Furthermore, optionally, to verify whether or not the radar system 202 is facing towards the region of interest (ROI) 204, a reflector is mounted on a railway crossing barrier positioned at the railway level-crossing. When the railway crossing barrier is lowered, the reflector reflects a portion of the electromagnetic radar radiation in a predictable manner. Moreover, when an obstacle, for example, such as a lorry stands adjacent to the railway crossing barrier, the signal processing arrangement of the radar system 202 is operable to determine whether or not the obstacle is outside the railway level-crossing. FIG. 2 is merely an example, which should not unduly limit the scope of the claims herein. A person skilled in the art will recognize many variations, alternatives, and modifications of embodiments of the present disclosure. FIGs. 3A and 3B collectively are a schematic illustration of a radar system 300, in accordance with an embodiment of the present disclosure. The radar system 300 includes an antenna arrangement 302, an array of driver modules 304, high-speed heterodyne circuits (H) 306, a signal processing arrangement {"digital signal processing" , DSP) 308, and an array of receiver modules 310. Optionally, the antenna arrangement 302 is implemented by way of an antenna array arrangement that includes a plurality of antenna sub-elements 30.

The driver modules 304 are coupled to the individual antenna sub-elements 30 of the antenna arrangement 302 for driving the antenna sub-elements 30 to emit electromagnetic radar radiation. The driver modules 304 allow for adjustment of phase (Θ) and/or amplitude (G) of drive signals applied to the individual antenna sub-elements 30 to achieve a desired polar characteristic of emission.

The receiver modules 310 are coupled to the individual antenna sub-elements 30 of the antenna arrangement 302. The receiver modules 310 allow for adjustment of phase (Θ) and/or amplitude (G) of signals received thereat from their respective antenna sub-elements 30 to achieve a desired polar characteristic of reception. Optionally, phase (Θ) and/or amplitude (G) adjustments applied by the driver modules 304 and/or the receiver modules 310 are controlled by the signal processing arrangement (" digital signal processing" , DSP) 308.

Optionally, the signal processing arrangement {"digital signal processing" , DSP) 308 is implemented using one or more reduced instruction set computer (RISC) processors of a digital signal processing (DSP) apparatus. Optionally, the signal processing arrangement (" digital signal processing" , DSP) 308 includes computing hardware and is operable to execute one or more software products to control its operation.

Moreover, the driver modules 304 and/or the receiver modules 310 are coupled via the high-speed heterodyne circuits (H) 306, to shift their signals from a lower base- band frequency to a high operating radar frequency, and/or to shift their signals from a high operating radar frequency to a lower base-band frequency, respectively, so that base-band signals can be handled via the signal processing arrangement (" digital signal processing" , DSP) 308.

Optionally, the radar system 300 is operable to generate the electromagnetic radar radiation in a frequency range of 10 GHz to 200 GHz. More optionally, the radar system 300 is operable to generate the electromagnetic radar radiation in a frequency range of 15 GHz to 150 GHz. Yet more optionally, the radar system 300 is operable to generate the electromagnetic radar radiation at a frequency of substantially 77 GHz. Alternatively, optionally, the radar system 300 is operable to generate the electromagnetic radar radiation at a frequency of substantially 24 GHz. FIGs. 3A and 3B are merely examples, which should not unduly limit the scope of the claims herein. A person skilled in the art will recognize many variations, alternatives, and modifications of embodiments of the present disclosure.

FIGs. 4A to 4D are schematic illustrations of a radar radiation reflecting target for use with the radar system of FIG. 2, in accordance with various embodiments of the present disclosure.

FIG. 4A is a schematic illustration of a planar radar radiation reflecting target 402 for use with the radar system of FIG. 2, in accordance with an embodiment of the present disclosure. As shown, the planar radar radiation reflecting target 402 includes one planar reflecting surface. The planar radar radiation reflecting target 402 is mounted on a pole 404. Optionally, the planar radar radiation reflecting target 402 may be operable to serve to function as an advertising or visual information bill board.

FIG.4B is a schematic illustration of a trihedral corner reflector 406 for use with the radar system of FIG. 2, in accordance with another embodiment of the present disclosure. The trihedral corner reflector 406 is shown mounted on a tripod 408.

FIG. 4C is a schematic illustration of a tubular radar reflecting target 410 for use with the radar system of FIG. 2, in accordance with yet another embodiment of the present disclosure. The tubular radar reflecting target 410 includes a mounting arrangement 412 for providing movement to the tubular radar reflecting target 410. The mounting arrangement 412 may be a rotatable actuating platform, linear actuating platform, and so forth. The tubular radar radiation reflecting target 410 beneficially has radar radiation reflecting properties that vary as a function of angle around its circumference, around about its central elongate axis. Such variation can be provided by including projections and/or holes in a radiation reflecting circumferential wall of the tubular target 410, or by varying a material composition of the tubular target 410 as a function of angle around its circumference. The mounting arrangement 412 is, for example, as a motor-driven rotatable platform, for example a stepper-motor driven rotatable platform, a servo-control rotatable platform or similar. It may be evident that the mounting arrangement 412 may be a rotatable actuating platform, a linearly-moving actuating platform, and so forth.

FIG. 4D is a schematic illustration of an octahedral radar reflecting target 414 for use with the radar system of FIG. 2, in accordance with yet another embodiment of the present disclosure. As shown, the octahedral radar reflecting target 414 includes a mounting arrangement 416. It may be evident that the mounting arrangement 416 may be a rotatable actuating platform, a linearly-moving actuating platform, and so forth.

FIGs. 4A to 4D are merely examples, which should not unduly limit the scope of the claims herein. A person skilled in the art will recognize many variations, alternatives, and modifications of embodiments of the present disclosure. Modifications to embodiments of the invention described in the foregoing are possible without departing from the scope of the invention as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "consisting of", "have", "is" used to describe and claim the present invention are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. Numerals included within parentheses in the accompanying claims are intended to assist understanding of the claims and should not be construed in any way to limit subject matter claimed by these claims.