IL192069A

IL192069A - Safety apparatus for an automatic self-defence system

Info

Publication number: IL192069A
Application number: IL192069A
Authority: IL
Original assignee: Diehl Bgt Defence Gmbh & Co Kg
Priority date: 2007-06-21
Filing date: 2008-06-11
Publication date: 2014-06-30
Also published as: DE102007028677A1; EP2009463A3; EP2009463A2; IL192069A0; EP2009463B1

Description

SAFETY APPARATUS FOR AN AUTOMATIC SELF-DEFENCE SYSTEM Pearl Cohen Zedek Latzer P-70967-IL BP 196 IL CM/Fi/bu Diehl BGT Defence GmbH & Co. KG, Alte NuBdorfer Strage 13.88662 OberHngen Safety apparatus for an automatic self-defence system The invention relates to a safety apparatus according to the precharacterizing clause of Claim 1 , for an automatic self-defence system.

Until now, there has been no clear definition as to how the system safety of an effective-distance defence system, referred to in the following text as AWiSS - can be ensured, subject to the requirement of obtaining licensing for the AWiSS. Evidence is required for this purpose.

The approaches known so far for obtaining evidence relating to the system safety of an AWiSS have assumed that thei system safety is provided within the fire control software, that is to say in the fire control computer. In this case, the aim is to draw a distinction between real and false targets by evaluation of the target data produced from radar Doppler signals and of a flight path resulting from this. This is because radar Doppler signals are one reliable possible way to classify the relative velocity of target objects. A safety circuit for the AWiSS evaluates the radar signals to determine whether the Doppler frequencies which are typical of a threat are present. The safety-relevant system components of the AWiSS are activated only if a threat is detected.

The invention is based on the object of providing a safety apparatus of the type mentioned initially, in which the verification of the system safety of the safety apparatus can be provided by comparatively simple means, in order to obtain a licence for the AWiSS.

According to the invention, this object is achieved by the features of Claim 1. Preferred embodiments and developments of the safety apparatus according to the invention are characterized in the dependent claims. i I I The safety apparatus according to the invention has the advantage that the implementation of system safety is separated from the tasks of fire control, which comprises the achievement of a high hit probability.

The raw radar data, that is to say the radar Doppler signals, is/are evaluated in parallel with the fire-control computer system by the use of a safety apparatus which as far as possible is composed entirely of hardware, in order to detect whether an object with the velocity of a real target is located in the field of view of the radar.

The firing circuits for the AWiSS are! enabled only when the safety apparatus detects a corresponding object so that, for example, a defensive shell can be fired.

According to the invention, system safety is therefore achieved by a safety circuit which is composed as far as possible only of hardware.

In comparison to this, in the already known solution approaches, all of the system software must be provided as safety-critical software, from the radar receiving device via the firing control to the generation of the firing signal. In this case, the creation and qualification of the software involves a considerably greater amount of development effort, that is to say greater by several factors. Furthermore, the qualification effort is incurred repeatedly whenever the software is modified during the product life cycle.

In contrast, according to the invention, strict separation is advantageously provided between the system safety function, that is to say fire enable, and the fire control task, that is to say the firing direction and the firing time. According to the invention, the fire-control system computer can initiate a countermeasure only when the safety circuit produces a fire enable. According to the invention, therefore, arming takes place only when the safety circuit detects a threat and issues a fire enable.

Further details, features and advantages will become evident from the following description of the safety apparatus according to the invention, in conjunction with the attached drawings, in which: Figure 1 shows a block diagram of a first embodiment of the safety apparatus, and Figure 2 shows a block diagram of a second embodiment of the safety apparatus.

Figure 1 schematically illustrates one embodiment of the safety apparatus 10 for an automatic self-defence system. The safety apparatus 10 has a radar receiving device 12, which is connected via a radar signal processing device 14 to an effective-distance defence system AWiSS, that is to say a system controller and fire control 16. The AWiSS 16 is connected to a safety and arming device 18.

A safety circuit 20 is connected in parallel with the radar signal processing device 14 and the AWiSS 16 between the radar receiving device 12 and the safety and arming device 18, with the purpose of evaluating radar Doppler signals from the radar receiving device 12.

The safety circuit 20 has an output 22 which is intended to emit threat enable signals. The AWiSS 16 has an output 24 which is intended to emit firing signals which are generated by the fire control. The outputs 22 and 24 are jointly connected to inputs of an AND gate 30, whose output 32 is connected to the safety and arming device 18. The AND gate 30 forms one component of the safety and arming device 18.

Figure 1 schematically illustrates one embodiment of the safety apparatus 10 in the form of a block diagram, with the radar receiving device 12 having a single radar receiving module 34. In contrast, Figure 2 illustrates an embodiment of the safety apparatus 10 in which the radar receiving device 12 has a number of radar receiving modules 34a, 34b, ... 34n. The/each radar receiving module has two radar frequencies, one of which is fixed and the second is switchable for range measurement. Each radar receiving module 34a, 34b, ... 34n is jointly connected to a respectively associated safety circuit 20a, 20b, ... 20n. The safety circuits 20a, 20b, ... 20n have outputs 22a, 22b, ... 22n which are jointly connected to the inputs 36a, 36b, ... 36n of an OR gate 38. The OR gate 38 has an output 40, which is connected to the input 26 of the AND gate 30 of the safety and arming device 18.

In Figure 2 as well, the reference number 14 denotes the radar signal processing device, and the reference number 16 the AWiSS of the safety apparatus 10.

I The safety apparatus 10 operates as follows: The raw radar data, that is to say the radar Doppler signals, is or are evaluated in parallel to the fire control by the safety circuit 20. When a Doppler signal which corresponds to a predetermined target spectrum is detected, then the safety circuit 20 generates an enable signal at the output 22. The safety and arming device 18 carries out an AND logic operation 30 between the fire enable - safety circuit 20 - and the fire-control fire signal which is produced at the output 24. The fire control can therefore fire only when the safety circuit 20 has previously issued a fire enable.

The AND gate 30 in the safety and arming device 18 deactivates all the firing circuits by ensuring there is no energy; in them, until an enable signal is produced at the output 22.

The radar provided for the AWiSS 16 uses two radar frequencies per radar receiving module 34a, 34b, ... 34n, in which case one of the two frequencies is fixed, and the second frequncy can be switched for range measurement purposes, as has already been mentioned. It is advantageous for the safety apparatus 10 to use two frequencies, because the reliability of the safety apparatus 10 is further improved by independent evaluation of the two frequencies.

The radar provided for the AWiSS advantageously uses four receiving elements per radar receiving module 34a, 34b, ... 34n, and these receiving elements are arranged as quadrants. Downstream from each of the four receiving elements, the received radar signals are expediently, mixed with the transmitted frequencies by means of mixers, to the video band. Downstream from the mixers for the receiving elements, the signals are referred to as raw radar signals, with each radar receiving element preferably generating four raw radar signals, specifically: Frequency 1 I channel (in-phase), Frequency 2 Q channel (quadrature phase), Frequency 2 I channel (in-phase), and Frequency 2 Q channel (quadrature phase).

Each radar receiving module 34a, 34b, ... 34n therefore produces sixteen analogue raw signals, which can be evaluated by the safety circuit 20. The number of. raw signals evaluated by the safety circuit 20 can be chosen as required. The number of raw radar signals evaluated increases the reliability of the safety apparatus 10.

In order to comply with the safety requirements, at least two of the radar channels must be evaluated. This means that the safety circuit 20 analyzes the Doppler frequencies in at least two of the analogue radar channels.

Various evaluation methods which are known per se may be used to determine the Doppler frequencies. For example, the evaluation in the circuit may be carried out by filter banks or an FFT (= Fast Fourier Transformation) by means of FPGA (the FPGA is an EPROM, that is to say software burnt into hardware). The specific type of signal processing is : irrelevant to the invention, although care should be taken to ensure that, as far as possible, no processors are used, because the use of processors and associated software necessitates more complex qualification.

When the safety circuit 10 detects an object at a predetermined velocity (Doppler frequency), then the safety and arming device 18 enables the firing lines so that the fire control system can, for example, fire a defensive shell. In this case, care must be taken to ensure that two independent enable signals must be provided for enabling, that is to say enabling via two separate channels.

I As long as no objects at the predetermined velocity (Doppler frequency) are detected, the safety and arming device 18 locks all the safety-relevant signals so that this ensures system safety independently of the fire control system for the safety apparatus 10 according to the invention. System safety can in consequence be ensured without any consideration of the fire control system, thus advantageously making it possible to dispense with complex qualification of the software.

According to the invention, the evaluation circuit may also have a microcontroller, that is to say it is also possible to use a microcontroller to evaluate the raw radar data. A software solution such as this admittedly means that the qualification is more complex; however, the software required for this purpose is advantageously considerably less complex, so that the qualification effort is still considerably less than if it were necessary to quality all of the fire control software.

Figure 2 shows an embodiment of the safety apparatus 10, comprising a number of radar receiving modules 34a, 34b, ... 34n, with each radar receiving module having an associated safety circuit 20a, 20b, ... 20n. At least two channels must be evaluated downstream from each radar receiving module. The aim is for enabling by the safety and arming device 18 when a threat exists in one of the radar receiving modules. The enable signals of the various radar receiving module 34a, 34, ... 34n are therefore in the form of an OR logic operation 38.

One central aspect of the present invention is therefore separation of fire control computation from system safety.

The fire control calculation (FLR), that is to say the functional unit (first functional block), which calculates the so-calledi fire control solution is responsible for the entire complex technical field of tracking (that is to say the following problem: the approaching projectile is at the point X at the time t0→ at what point Y will it be at at the time t-i), and for calculation of the point at which the defensive projectile intercepts the approaching projectile (= real target).

The FLR, that is to say in this case the AWiSS, is generally always active: moving objects in the detection area are automatically measured continuously and data for intercept manoeuvres is also calculated, but without actually initiating any countermeasure.

The system can in fact not actually initiate any countermeasure until the second functional block, the system safety, has issued an enable. In the simplest case, this system safety may be a button which is pressed by the human system operator. From this time, the system is "live", that is to say the system firing capacitors are charged and the system is in general in a state to initiate a countermeasure.

However, there is therefore in principle also a risk of the system also attacking targets which should not be engaged (that is to say for example civil objects such as passenger vehicles, objects thrown out, etc.). In the prior art, target discrimination is carried out by the person who tells the system what a real target is and what is not (specifically by pressing the initiation button if the decision is positive, and with the system initiating the countermeasure). However, in general, the system is in an unsafe state after "arming", because the system which continuously calculates countermeasures is now only kept in check just by a person. 1 One aim of the invention is now "to make the armed system safe", that is to say in some way to prevent the system from firing at a non-real target.

According to the invention, the target discrimination is in this case used for safety, and is fed directly with the raw signals from the radar and Doppler sensors. This means that the safety circuit firstly makes the decision just on the basis of the raw data: this relates to a real target (for example because it is flying very fast), that is to say completely non-specifically without any calculation of the flight path of the projectile. The safety circuit then issues a general fire enable. However, this does not automatically mean that the system will also actually fire, because the FLR can, for example, calculate that the approaching object will fly past and there is no need at all for any countermeasure. Only if the continuously active FLR considers on the basis of continuous track calculation that a countermeasure is necessary will it itself issue a fire command (AND logic operation) and actually initiate the countermeasure.

However, the fire command for the FLR leads to a return shot being fired only if the safety circuit has issued the fire enable. Therefore, in the end, the two signals from the safety circuit and from FLR must be linked by an AND logic operation in order to initiate the countermeasure.

Both system components, that is to say the FLR and the safety circuit, are fed with the raw data from the radar and Doppler sensors, but, while the FLR uses this to calculate the track data for the approaching projectile and to calculate (hypothetical) countermeasures, the safety circuit just uses the same data to determine whether this is in general a real target at all (for example because it is fast enough, an object thrown by hand generally does not fly fast enough and is, so to speak, segregated as an non-real target).

The operation of the safety circuit is therefore removed form the pure FLR, and is separated from it. This allows the FLR to be modified without having to requalify it, because the safety circuit in fact remains unchanged.

List of Reference Numbers: Safety apparatus 12 Radar receiving device (of 10) 14 Radar signal processing device (of 10) 16 AWiSS (of 10) 18 Safety and arming device (of 10) Safety circuit (of 10) 22 Output (of 20) 24 Output (of 6) 26 Input (of 30) 28 Input (of 30) AND gate (of 18) 32 Output (of 30) 34 Radar receiving module (of 12) 36 Input (of 38) 38 OR gate (of 10) 40 Output (of 38)

Claims

1. Safety apparatus for an automatic self-defence system having a radar receiving device (12) which is connected via a radar signal processing device (14) to an effective-distance defence system (AWiSS) (16), which is connected to a safety and arming device (18), characterized in that a safety circuit (20) which evaluates radar Doppler signals is connected in parallel with the radar signal processing device (14) and the AWiSS (16) between the radar receiving device (12) and the safety and arming device (18), with the output (22) of the^afety circuit (20) and the output (24) of the AWiSS (16) being jointly connected to the inputs (26, 28) of an AND gate (30), whose output (32) is connected to the safety and arming device (18).

2. Safety apparatus according to Claim 1 , characterized in that the radar receiving device (12) has at least one radar receiving module (34).

3. Safety apparatus according to Claim 2, characterized in that the radar receiving device (12) has a number of radar receiving modules (34a, 34b, ... 34n).

4. Safety apparatus according to one of Claims 1 to 3, characterized in that the/each radar receiving module (34; 34a, 34b, ... 34n) has two radar frequencies, one of which is fixed and the second is switchable for range measurement.

5. Safety apparatus according to one of Claims 1 to 4, characterized in that the/each radar receiving module (34; 34a, 34b, ... 34n) has four receiving elements arranged as quadrants.

6. Safety apparatus according to Claim 5, characterized in that a mixing device is provided, in which the signals received by the receiving modules (34a, 34b, ... 34n) are mixed with the transmitted frequencies to a video band.

7. Safety apparatus according to Claim 5, characterized in that each receiving element generates four raw radar signals so that the/each radar receiving module (34; 34a, 34b, ... 34n) produces sixteen analogue raw radar signals.

8. Safety apparatus according to one of Claims 1 to 7, characterized in that an evaluation circuit is provided in order to evaluate the radar Doppler signals.

9. Safety apparatus according to Claim 8, characterized in that the evaluation circuit has filter banks.

10. Safety apparatus according to Claim 8, characterized in that the evaluation circuit has an FFT (Fast Fourier Transformation) by means of FPGA.

11. Safety apparatus according to Claim 8, characterized in that the evaluation circuit has a microcontroller.

12. Safety apparatus according to one of Claims 1 to 11 , characterized in that the safety circuit (20) which evaluates the radar Doppler signals has a number of safety circuits (20a, 20b, ... 20n) corresponding to the number of radar receiving modules (34a, 34b, ... 34n), each with an associated evaluation circuit.

13. Safety apparatus according to Claim 12, characterized in that the outputs (22a, 22b, ... 22n) of the safety circuits (20a, 20b, ... 20n) are jointly connected to the inputs (36a, 36b, ... 36n) of an OR gate (38), whose output (40) is connected to the safety and arming device (18).

14. Safety apparatus according to any one of claims 1-13 substantially as described hereinabove.

15. Safety apparatus according to any one of claims 1-13 substantially as illustrated in any of the drawings.