Patent Application
20240308660
The disclosure relates to a pyrotechnical countermeasure dispenser system and a method for dispensing detection of a pyrotechnical countermeasure in a pyrotechnical countermeasure dispenser system. The pyrotechnical countermeasure dispenser system comprises a pyrotechnical countermeasure dispenser, at least one pyrotechnical countermeasure cartridge arranged to be fitted in the pyrotechnical countermeasure dispenser, and a pyrotechnical countermeasure dispenser control unit configured for controlling the dispensing of the pyrotechnical countermeasure from the pyrotechnical countermeasure cartridge.
Pyrotechnical countermeasure dispensing systems for deploying countermeasures such as chaff and flares in response to threats directed towards a mobile platform equipped with such a pyrotechnical countermeasure dispensing systems. Examples of such systems can for instance be found in US 2015/0331417 A1 or U.S. Pat. No. 4,313,379.
The pyrotechnical countermeasure is dispensed from a pyrotechnical countermeasure cartridge arranged in the pyrotechnical countermeasure dispenser by means of a squib charge that is set off by means of a dispensing command initiated by a pilot of the mobile platform or by an automatic command upon detection and assessment of an incoming threat. For each pyrotechnical countermeasure cartridge, a bridgewire is connected to a squib. Upon initiation of a dispensing command, current is run through the bridgewire that heats the bridgewire to a high temperature. This starts an exothermic chemical reaction of an attached pyrotechnic composition that in turn sets of the squib, dispensing the contents of the pyrotechnical countermeasure cartridge, e.g. chaff or flare.
One problem that can arise in a pyrotechnical countermeasure dispenser is a misfire of a pyrotechnical countermeasure cartridge meaning that dispensing does not occur, even though a dispensing command has been issued. Today, a dispensing current is measured through the bridgewire and dispensing is deemed successful is a dispensing current has been properly detected. This is however not always the case as the squib may not detonate even though the bridgewire has ignited in a desired way. A misfire causes a number of problems, such as a pilot incorrectly believing that pyrotechnical countermeasure has been dispensed.
There is thus a need for an improved detection of misfire in pyrotechnical countermeasure dispenser systems.
An objective of this disclosure is to provide a method for dispensing detection of a pyrotechnical countermeasure in a pyrotechnical countermeasure dispenser system and a pyrotechnical countermeasure dispenser system that addresses the problems described above. This object is achieved by the technical features contained in the characterizing portion of independent claims 1 and 5. The dependent claims contain advantageous embodiments, further developments and variants of the method and system.
The disclosure relates to a method for dispensing detection of a pyrotechnical countermeasure in a pyrotechnical countermeasure dispenser system. The pyrotechnical countermeasure dispenser system comprises a pyrotechnical countermeasure dispenser, at least one pyrotechnical countermeasure cartridge arranged to be fitted in the pyrotechnical countermeasure dispenser, and a pyrotechnical countermeasure dispenser control unit configured for controlling the dispensing of the pyrotechnical countermeasure from the pyrotechnical countermeasure cartridge. The method comprises:
By adding a recoil-sensing device to the electronic circuitry of the pyrotechnical countermeasure dispenser, i.e. to a pyrotechnical countermeasure dispenser control unit, it is possible to monitor the presence or absence of a recoil signal generated by the recoil-sensing device during a period of time, i.e. a monitoring window, after a pyrotechnical countermeasure dispensing command is generated to dispense the pyrotechnical countermeasure. This allows for an improved detection of if a pyrotechnical countermeasure has been dispensed or not compared to today's methods.
When a pyrotechnical countermeasure dispensing command is generated, a dispensing current through a bridgewire connected to a squib charge in the pyrotechnical countermeasure cartridge is measured. Previously, the detection of a dispensing current was deemed enough to indicate a successful dispensing of the pyrotechnical countermeasure. However, as described above, this is not always the case. By supplementing the dispensing current detection with the detection of a recoil signal from a recoil-sensing device in the pyrotechnical countermeasure dispenser control unit, a more certain detection of fire or misfire of the pyrotechnical countermeasure can be made. If the recoil signal exceeds a recoil detection threshold value during the monitoring window, a successful dispensing is assumed. If there is no detection of the recoil signal during the monitoring window period, even if the dispensing current was detected as expected, a misfire is declared.
Further advantages are that in the case of an anomaly in the detection of the dispensing current with a subsequent detection of a recoil signal by the recoil-sensing device can initiate a misfire compensation (if so wished or required) much earlier than is possible with the current implementation.
The pyrotechnical countermeasure dispenser system may be arranged in a platform, wherein the method comprises:
If the pyrotechnical countermeasure dispenser system is arranged in a platform, background noise signals in the recoil-sensing device will be present, for instance from vibrations from the platform. A recoil signal level of the recoil signal detected by the recoil-sensing device in the monitoring window is normally greater than a noise signal level generated by platform vibrations. In order to always make sure that the background noise signal does not cause any recoil signal detection issues, the noise signal value of the background noise signal from the platform is continuously or intermittently measured and the recoil detection threshold value is adjusted to a predetermined value above the noise signal value of the background noise signal from the platform. In this way, should the noise signal value approach the recoil detection threshold value, the recoil detection threshold value is adjusted such that the background noise signal value itself cannot be mistaken for a recoil signal.
The method may comprise:
The dispensing detection can also serve as a safety enhancing mechanism to inhibit simultaneous dispensing within the sensing window period, up to the point the impulse is detected before allowing subsequent dispensing to be allowed.
The method may comprise:
Monitoring the health status of both the pyrotechnical countermeasure dispenser and a mounting interface to the platform can be performed by continuously monitoring the vibration levels during flight and usage. When abnormal vibration frequencies start to become evident, this can be used as an early indicator to service or replace parts even on platform level. This can hugely benefit platforms that does not have a vibration monitoring Health and Usage Monitoring System (HUMS). On-condition servicing will greatly improve the availability of the equipment.
The disclosure further relates to a pyrotechnical countermeasure dispenser system comprising a pyrotechnical countermeasure dispenser, at least one pyrotechnical countermeasure cartridge arranged to be fitted in the pyrotechnical countermeasure dispenser, and a pyrotechnical countermeasure dispenser control unit configured for controlling the dispensing of the pyrotechnical countermeasure from the pyrotechnical countermeasure cartridge. The dispenser control unit further comprises a recoil-sensing device. The dispenser control unit upon activation of a pyrotechnical countermeasure dispensing command is configured for monitoring the sensing of a recoil signal from the recoil-sensing device during a monitoring window, determining that dispensing of the pyrotechnical countermeasure has occurred upon detection of the recoil signal exceeding a recoil detection threshold value during the monitoring window, and determining that a misfire of the pyrotechnical countermeasure has occurred if no detection of the recoil signal is made during the monitoring window.
The advantages for the system are the same as described for the method above.
The recoil-sensing device may be a load cell or a three-axis accelerometer.
These alternatives are inexpensive and easy to implement in the pyrotechnical countermeasure dispenser control unit.
The dispenser control unit may comprise two or more recoil-sensing devices.
In order to obtain redundancy or to increase accuracy in detection, more than one recoil-sensing device may be used. In case more than one recoil-sensing device is used, they do not have be of the same type. I.e., one recoil-sensing device can be a load cell and one recoil-sensing device can be a three-axis accelerometer.
The pyrotechnical countermeasure dispenser system may be arranged in a platform, wherein the dispenser control unit may be configured for:
The advantages for the system are the same as described for the method above.
The dispenser control unit may be configured for
The advantages for the system are the same as described for the method above.
The dispenser control unit may be configured for
The advantages for the system are the same as described for the method above.
The disclosure further comprises a platform comprising a pyrotechnical countermeasure dispenser system according to the above description.
The platform may be an aircraft such as an airplane or a helicopter.
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.
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.
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.
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.
As is shown in
The dashed lines schematically show the start at t=0 and the end at t=tM 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.
The dashed lines schematically show the start at t=0 and the end at t=tM 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.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2100024-5 | Feb 2021 | SE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/SE2022/050146 | 2/11/2022 | WO |
