METHOD AND SYSTEM FOR DISPENSING DETECTION OF A PYROTECHNICAL COUNTERMEASURE

Abstract

The disclosure relates to a system and a method for dispensing detection of a pyrotechnical countermeasure in a pyrotechnical countermeasure dispenser system (1). The method comprises: providing a pyrotechnical countermeasure dispenser control unit (4) with a recoil-sensing device (5), wherein upon activation of a pyrotechnical countermeasure dispensing command, monitoring the sensing of a recoil signal (8) from the recoil-sensing device (5) during a monitoring window (6), determining that a dispensing of the pyrotechnical countermeasure from a pyrotechnical countermeasure cartridge (3) has occurred upon detection of the recoil signal (8) exceeding a recoil detection threshold value (9) during the monitoring window (6), determining that a misfire of the pyrotechnical countermeasure has occurred upon no detection of the recoil signal (8) during the monitoring window (6).

Claims

1-12. (canceled)

13. Method for dispensing detection of a pyrotechnical countermeasure in a pyrotechnical countermeasure dispenser system (1), wherein the pyrotechnical countermeasure dispenser system (1) comprises a pyrotechnical countermeasure dispenser (2), at least one pyrotechnical countermeasure cartridge (3) arranged to be fitted in the pyrotechnical countermeasure dispenser (2), and a pyrotechnical countermeasure dispenser control unit (4) configured for controlling the dispensing of the pyrotechnical countermeasure from the pyrotechnical countermeasure cartridge (3), wherein the method comprises: providing the pyrotechnical countermeasure dispenser control unit (4) with a recoil-sensing device (5), and upon activation of a pyrotechnical countermeasure dispensing command: monitoring the sensing of a recoil signal (8) from the recoil-sensing device (5) during a monitoring window (6), determining that a dispensing of the pyrotechnical countermeasure from the pyrotechnical countermeasure cartridge (3) has occurred upon detection of the recoil signal (8) exceeding a recoil detection threshold value (9) during the monitoring window (6), and determining that a misfire of the pyrotechnical countermeasure has occurred upon no detection of the recoil signal (8) during the monitoring window (6).

14. Method according to claim 13, wherein the pyrotechnical countermeasure dispenser system (1) is arranged in a platform and the method further comprises: measuring a noise signal value of a background noise signal from the platform, and adjusting the recoil detection threshold value (9) to a predetermined value above the noise signal value of the background noise signal from the platform.

15. Method according to claim 14, wherein the method further comprises preventing a subsequent dispensing of a further pyrotechnical countermeasure from the pyrotechnical countermeasure dispenser (2) until a recoil signal (8) exceeding a recoil detection threshold value (9) is detected.

16. Method according to claim 13, wherein the method further comprises preventing a subsequent dispensing of a further pyrotechnical countermeasure from the pyrotechnical countermeasure dispenser (2) until a recoil signal (8) exceeding a recoil detection threshold value (9) is detected.

17. Method according to claim 13, wherein the method further comprises measuring vibrations continuously with the recoil-sensing device (5) to monitor the health status of the pyrotechnical countermeasure dispenser (2) and other platform systems.

18. Pyrotechnical countermeasure dispenser system (1) comprising: a pyrotechnical countermeasure dispenser (2), at least one pyrotechnical countermeasure cartridge (3) arranged to be fitted in the pyrotechnical countermeasure dispenser (2), and a pyrotechnical countermeasure dispenser control unit (4) configured for controlling the dispensing of the pyrotechnical countermeasure from the pyrotechnical countermeasure cartridge (3), wherein: the dispenser control unit further comprises a recoil-sensing device (5), the dispenser control unit upon activation of a pyrotechnical countermeasure dispensing command is configured for monitoring the sensing of a recoil signal (8) from the recoil-sensing device (5) during a monitoring window (6), determining that a dispensing of the pyrotechnical countermeasure has occurred upon detection of the recoil signal (8) exceeding a recoil detection threshold value (9) during the monitoring window (6), and determining that a misfire of the pyrotechnical countermeasure has occurred if no detection of the recoil signal (8) is made during the monitoring window (6).

19. Pyrotechnical countermeasure dispenser system (1) according to claim 18, wherein the recoil-sensing device (5) is a load cell or a three-axis accelerometer.

20. Pyrotechnical countermeasure dispenser system (1) according to claim 19, wherein the dispenser control unit comprises two or more recoil-sensing devices (5).

21. Pyrotechnical countermeasure dispenser system (1) according to claim 18, wherein the dispenser control unit comprises two or more recoil-sensing devices (5).

22. Pyrotechnical countermeasure dispenser system (1) according to claim 18, wherein the pyrotechnical countermeasure dispenser system (1) is arranged in a platform and the pyrotechnical countermeasure dispenser control unit (4) is configured for: measuring a noise signal value of a background noise signal from the platform, and adjusting the recoil detection threshold value (9) to a predetermined value above the noise signal value of the background noise signal from the platform.

23. Pyrotechnical countermeasure dispenser system (1) according to claim 18, wherein the pyrotechnical countermeasure dispenser control unit (4) is configured for preventing a subsequent dispensing of a further pyrotechnical countermeasure from the pyrotechnical countermeasure dispenser (2) until a recoil signal (8) exceeding a recoil detection threshold value (9) is detected.

24. Pyrotechnical countermeasure dispenser system (1) according to claim 18, wherein the pyrotechnical countermeasure dispenser control unit (4) is configured for measuring vibrations continuously with the recoil-sensing device (5) to monitor the health status of the pyrotechnical countermeasure dispenser (2) and other platform systems.

25. Platform comprising the pyrotechnical countermeasure dispenser system (1) according to claim 18.

26. Platform according to claim 25, wherein the platform is an aircraft.

27. Platform according to claim 26, wherein the aircraft is an airplane or a helicopter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG. 1 schematically shows a pyrotechnical countermeasure dispenser system according to the disclosure,

[0044] FIGS. 2a-2c schematically show a sequence of recoil detection from firing a pyrotechnical countermeasure where a recoil signal is detected,

[0045] FIGS. 3a-3c schematically show a sequence of recoil detection from firing a pyrotechnical countermeasure where a recoil signal is not detected.

DETAILED DESCRIPTION

[0046] As used herein, a platform is generally intended to refer to a mobile platform such as an aircraft. Examples of aircraft are airplanes or helicopters. Mobile platforms may also refer to land or sea based mobile platforms such as land vehicles and watercraft such as ships and boats. The mobile platform may be manned or unmanned.

[0047] The pyrotechnical countermeasure dispenser system is arranged to prevent damage from threats directed towards the mobile platform. These threats include tube-dispensed, optically tracked, wire-guided missiles (TOWs), rocket propelled grenades (RPGs), shoulder-dispensed surface-to-air missiles (SAMs), man-portable air-defence systems (MANPADS or MPADS) and similar aerial weapons.

[0048] FIG. 1 schematically shows a pyrotechnical countermeasure dispenser system 1 according to the disclosure. The pyrotechnical countermeasure dispenser system 1 comprises a pyrotechnical countermeasure dispenser 2, at least one pyrotechnical countermeasure cartridge 3 arranged to be fitted in the pyrotechnical countermeasure dispenser 2, and a pyrotechnical countermeasure dispenser control unit 4 configured for controlling the dispensing of the pyrotechnical countermeasure from the pyrotechnical countermeasure cartridge 3. In the example shown in FIG. 1, the pyrotechnical countermeasure dispenser 2 comprises five different pyrotechnical countermeasure cartridges 3, each arranged to be fitted with chaff or flare expendables. The pyrotechnical countermeasure dispenser 2 with the pyrotechnical countermeasure cartridges 3 is mounted on the pyrotechnical countermeasure dispenser control unit 4 as is known in the art today.

[0049] The pyrotechnical countermeasure cartridges 3 are operated in the same way as is known today by means of igniting a squib charge connected to a bridgewire. When dispensing of a pyrotechnical countermeasure cartridge 3 is initiated, the current through the bridgewire is measured to detect if dispensing of the pyrotechnical countermeasure cartridge 3 has taken place. The method and system of the disclosure are intended to complement this known technology to improve detection accuracy and reliability. The workings of pyrotechnical countermeasure cartridges 3 will not be described in more detail.

[0050] The pyrotechnical countermeasure dispenser control unit 4 is a printed circuit board (PCB) comprising all the necessary circuitry required to operate the pyrotechnical countermeasure dispenser 2 and to communicate with a platform control unit of a platform onto which it is installed. On the pyrotechnical countermeasure dispenser control unit 4, a recoil-sensing device is installed in order to detect the dispensing of pyrotechnic countermeasures. Necessary adaptations are made to the pyrotechnical countermeasure dispenser control unit 4 such that the recoil-sensing device can send and/or receive information to/from the platform control unit. Such adaptations include providing a fitting for the recoil-sensing device and etching conductive traces to control interfaces on the pyrotechnical countermeasure dispenser control unit 4. These adaptations are well known in the art and will not be described in detail here.

[0051] As is shown in FIG. 1, the pyrotechnical countermeasure cartridges 3 are arranged such that they dispense their content in a dispensing direction DD. When a pyrotechnical countermeasure is dispensed, a recoil force acting in a recoil direction DR, essentially in the opposite direction of the dispensing direction DD, is exerted on the platform and thereby on the pyrotechnical countermeasure dispenser control unit 4. As the recoil-sensing device is arranged on the pyrotechnical countermeasure dispenser control unit 4, a recoil signal can be detected by the recoil-sensing device when the pyrotechnical countermeasure is dispensed successfully.

[0052] FIGS. 2a-2c schematically show a sequence of recoil detection from firing a pyrotechnical countermeasure where a recoil signal is detected. In FIGS. 2a-2c, a monitoring window 6, a firing pulse 7 and a recoil signal 8 are shown in the same chart, with time t on the x-axis.

[0053] FIG. 2a schematically show a monitoring window 6. The length t.sub.M of the monitoring window 6 is approximately between 100 and 300 milliseconds, specifically between 150 and 250 milliseconds, more specifically approximately 200 milliseconds. The monitoring starts upon activation of a pyrotechnical countermeasure dispensing command.

[0054] FIG. 2b schematically shows a firing pulse 7 originating from the activation of a pyrotechnical countermeasure dispensing command and occurs at a slight delay from the start of the monitoring. The firing pulse 7 activates the squib charge through the bridgewire.

[0055] FIG. 2c schematically shows a recoil signal 8 as measured by the recoil-sensing device. As is schematically shown, a recoil detection threshold value 9 is set above a noise signal value (not shown) in order to prevent misdetections due to vibrations from the platform. As mentioned above, the recoil detection threshold value 9 can be dynamically adjusted to adapt for differences in vibrations of the platform over time. The recoil signal 8 exceeds the recoil detection threshold value 9 during the monitoring window 6 indicating that the pyrotechnical countermeasure has been dispensed properly.

[0056] The dashed lines schematically show the start at t=0 and the end at t=t.sub.M of the monitoring window 6 in relation to both the firing pulse 7 and the recoil signal 8. As is shown, a recoil signal 8 is detected within the monitoring window 6. As is already known, the current through the bridgewire is measured and the combination of the measurement of current through the bridgewire and the measurement of a recoil signal 8 exceeding the recoil detection threshold value 9 is used to detect a successful dispensing of pyrotechnical countermeasure.

[0057] FIGS. 3a-3c schematically show a sequence of recoil detection from firing a pyrotechnical countermeasure where a recoil signal is not detected. In FIGS. 3a-3c, a monitoring window 6, a firing pulse 7 and a recoil signal 8 are shown in the same chart, with time t on the x-axis in the same way as in FIGS. 2a-2c.

[0058] FIG. 3a schematically show a monitoring window 6. The length t.sub.M of the monitoring window 6 is approximately between 100 and 300 milliseconds, specifically between 150 and 250 milliseconds, more specifically approximately 200 milliseconds. The monitoring starts upon activation of a pyrotechnical countermeasure dispensing command.

[0059] FIG. 3b schematically shows a firing pulse 7 originating from the activation of a pyrotechnical countermeasure dispensing command and occurs at a slight delay from the start of the monitoring. The firing pulse 7 activates the squib charge through the bridgewire.

[0060] FIG. 3c schematically shows a recoil signal 8 as measured by the recoil-sensing device. As is schematically shown, a recoil detection threshold value 9 is set above a noise signal value (not shown) in order to prevent misdetections due to vibrations from the platform. As mentioned above, the recoil detection threshold value 9 can be dynamically adjusted to adapt for differences in vibrations of the platform over time.

[0061] The dashed lines schematically show the start at t=0 and the end at t=t.sub.M of the monitoring window 6 in relation to both the firing pulse 7 and the recoil signal 8. As is shown, a recoil signal 8 is not detected within the monitoring window 6. For simplicity, the recoil signal is made flat. This can for instance be made by using filters to remove the noise that would otherwise cause the signal to vary over time. In this case, a dispensing current through the bridgewire is measured and the lack of a measurement of a recoil signal 8 exceeding the recoil detection threshold value 9 is used to detect a misfire of pyrotechnical countermeasure.

[0062] As will be realised, the invention is capable of modification in various obvious respects, all without departing from the scope of the appended claims. Accordingly, the drawings and the description are to be regarded as illustrative in nature, and not restrictive.