The present invention relates to the Counter Measures dispensing system for protection of aircraft against RF guided or IR homing missiles. The equipment is capable of dispensing chaff / flare or both to defeat the threat. The threat information shall be obtained from the RWR and the selection of the program and dispensation can be done manually or automatically.
In the present scenario most of the anti aircraft missiles used by terrorist group or the enemies are either IR homing or RF guided missiles. The present invention of CMDS will provide effective protection against this weapons.
The CMDS according to the invention is suitable for fitment and usage in fighter aircraft. It is very effective, user friendly and easily serviceable system.
The present invention of the CMDS consist of five sub units viz. control panel , firing controller, breech plate, magazine, and safety switch. The control panel and firing controller are the electronic item and each unit contains embedded microcontroller, associated analog and digital circuits and operational software. The other units are mechanical units used for holding and to extend the electrical connection to the chaff and flare.
CONTROL PANEL
General
The control panel is the only LRU which provides man/machine interface. The control panel is accessible to pilot through which pilot's command and control are executed and it provides the interface to the aircraft. The main functions of control panel are
• Man /machine interface to the system
• Serial communication with EW suit (RWR/SPJ) via mil 1553 bus
• Serial communication with firing controller via RS422

• Payload inventory display
• Selection of manual firing program
• Selection of RWR operation mode
• Dimmer control for displays
• Jettison switch for fast firing of flares
Mechanical Description
The control panel is enclosed in an aluminum box, the internal electronics are distributed in three PCB's. Two circular series III connectors and two 1553 communication connectors provided on the back panel. Housing : The housing is provided with rugged chassis covered with aluminum plates on top, bottom, front, and back. These plates when open provides access to the PCB's.
Front panel: The front panel consist displays and switches in a PCB housed in Perspex panel supported by front aluminum plate along with jettison switch, On /Off/Test switch and potentiometer. The Perspex panel has smaH bulbs to provide illumination of the text.
Back panel: The back panel provides the support to two circular connectors and two 1553 communication connectors. The first circular connector mates with air craft harness while other provides the interface to firing controller. The two communication connector mates with aircraft 1553B bus A and bus B for interface with EW suit (RWR/SPJ).
Electrical Description
The front panel consist of displays and push buttons & switches. The Alpha numeric displays provides the information about the mode of operation & functions and inventory. The push button and switches are provided to the pilot for command and control.
The operation of control panel is controlled by microcontroller in the CPU PCB through the software in the flash memory. The CPU translates the command and control from pilot and RWR to a command to firing controller via RS422 half duplex serial communication, whereas the response from the firing controller translated to the information for display. The CPU also

provides 1553 communication to EW suit(RWR). It accepts the command from RWR and replies the status to EW suit(RWR).
The power supply and relay PCB consist of a DC-DC converter to provides 5V supply for CPU with filters for EMI suppression. It also has the relay switching circuits to extend logic power and squib power to Firing controller.
FIRING CONTROLLER
General
The firing controller is the main unit of CMDS. It is not accessible to the pilot and it is controlled by discrete inputs and serial communication channel from control panel. The firing controller can be designed to have a number of firing programs. In a preferred embodiment they are explained in detail. Stores the 19 firing programs (16 user selectable through panel or RWR and 3 fixed program) and executes the selected firing program by activating the sequence of payload by pumping 5A current pulses on receiving the command from control panel. The firing controller provides following functions. ^ Serial communication with control panel during operation and with
FPDS during fire program data downloading. r Running BIT (Built In Test) during power ON. r Periodic Payload inventory check and update. r Executing the firing program with the logic's and features as defined. y EMI filtering on power lines and all inputs.
Mechanical Description:
The firing controller is enclosed in an rugged casting box made of aluminum with EMI gaskets. The housing cage accommodates the PCB's, rear plate holds the connector and front plate provides the enclosure.

Housing:
The housing cage is a rigid construction made of single casting. It supports four PCB by means of standard card retainers riveted on to the cage. It also provide support to the motherboard. Rear panel:
The rear panel is light weight rigid construction with cutouts for the mounting of the connectors which are wired to mother board. It also provides accommodation for the EMI filters. Front panel:
It is a light weight cover made of aluminum alloy. It provides a sealing of the unit. It is fitted with EMI gaskets to the housing.
Electrical Description:
The firing controller unit consist of five PCB's viz. CPU PCB, power supply PCB, two firing control PCB, and mother board. The mother board provides interconnection of all signal line and power lines between all PCB's.
The CPU PCB consists of 8751 microcontroller embedded with memory devices, I/O ports, communication driver IC's and reset IC. The CPU receives command from control panel and gives response back to the CP. The cpu also executes the firing program and performs inventory check and built-in test.
The firing control PCB consist of high current FETS to supply firing pulse to the individual squibs, it also contains latches and other circuits through which CPU controls the firing. The power supply PCB consist of DC-DC converter which generates the 5V and +/- 15V required for the CPU and other analog circuitry .
BREECH PLATE
The breech plate provides the physical connection between the firing controller and the magazine. It is designed with rugged metallic structures and the provided with proper mounting mechanism to secure the magazine with breech plate to withstand all mission stress and environmental conditions.

Each breech plate has a number of spring loaded firing contacts pins. The electrical connection is extended up to this pins from firing controller through harness. The Breech Plate when secured with magazine provides the interface from firing controller to the electrical squibs (payloads) in the magazine.
The magazine is secured to breech plate by four quick-release bolts. Two asymmetrical guide pin on the sides of the breech plate aligns the magazine to the breech plate in one position only.
Two pins identical to the firing pins are provided on both sides to decode the payload type loaded in magazine. The decoding is done by sensing the pin which touches ( or not touches) the body. Refer the magazine setup. MAGAZINE
This magazine is constructed with rugged light weight high strength metallic structures to hold and dispense chaff or flare. Based on the type of payload being carried and the size and number of the payload (dispensable) the magazine will be fabricated. By way examples, two types of magazines are explained here, i) magazine 1" X 1" to carry 30 Nos. of Chaff/Flare cartridges, ii) magazine 2"X 1" to carry 15 flare cartridges.
Two removable sensing screws on both sides of the magazine are provided to distinguish the payload type between chaff , dual chaff or flare 1" X 1" by decoding the presence of the screws electrically.
A retention plate is provided to hold the loaded cartridges while transportation and handling the loaded magazine. The cutouts in the retention plate allows the firing contact pin of the breech plate to mate with the squib in the magazine. SAFETY SWITCH
The safety switch with safety pin and flag provides safety to the system by isolating squib power from control panel to firing controller when safety pin is in place.

Salient feature of one of the embodiment under our invention are as under:
^ Three modes of function: operation mode, maintenance mode & training mode.
r Selection of RWR modes to manual, auto or semi auto from control panel.
^ Mil Std 1553B/RS422 interface with EW suit (RWR).
> Safety provision to avoid accidental firing on ground.
> 16 firing programs for user selection.
r High priority Jettison program for fast firing of all flares.
r Escape program for unknown threats.
r Doubling flares during after burner.
> Misfire detection and correction.
/- Power on BIT and periodic BIT.
y Continuous inventory display and update.
r Auto sensing or properly encoded payload type.
r User selectable critical quantity.
r Provision for STOP firing execution.
^ Failure and warning message for critical Qty, program execution etc on the
control panel.
r Brightness control for displays.

We claim
1. The counterMeasures dispensing system (CMDS) for protection of aircraft against radar guided & IR seeking, air & ground launched missiles and radar guided anti aircraft missiles comprises of (a) Control panel (b) Firing controller (c) Breech plate (d) Magazine and ( e) Safety switch. Capable of dispensing chaff or flare or any other expendables by sending a firing current up to 5A for 15 msec. The firing current is adjustable and interval between dispensation are programmable.
2. The CMDS as claimed in claim-1 is capable of operating with aircraft power supply 28V DC and does not require any additional power.
3. The CMDS as claimed in claim-1 is capable of fitting and operational in all types of fighter aircraft, helicopter and tanks.
4. The CMDS as claimed in claim-1 is capable of supporting plurality of magazine for dispensing chaffs and flare.
5. The CMDS as claimed in claim 4 is capable of supporting up to 4 magazines.
6. The CMDS as claimed in claim-1 where in the said control panel is capable of providing interface to aircraft, providing controls and display to pilot, providing serial communication and control with firing controller through RS422, and serial communication with RWR or SPJ through Mil 1553B bus or RS422.
7. The CMDS as claimed in claim-1 wherein the said firing controller is capable of storing a plurality of fire program parameters, provide serial communication with control panel, executes firing program as per the received command, provides inventory check and Built In Test.
8. The CMDS as claimed in claim 7 when is said firing controller is capable of storing preferable 19 program.

9. The CMDS as claimed in claim-8 the firing controller stored with 19 fire program parameters, where in 16 program are for user selection, 17th is for fast firing of flares through jettison command, 18th is for unknown threat through escape command and 19th is for RWR default.
10. The CMDS as claimed in claim-1 wherein the said breech plate is capable of providing electrical contact from firing controller to the squibs, provides mechanical support to the magazine.
11. The CMDS as claimed in claim-1 wherein the said magazine is capable of holding the chaff or flare, and provides enough mechanical support to the payloads during operation and firing.
12. The CMDS as claimed in claim-1 wherein the said safety switch is capable of disabling the accidental firing on ground by disconnecting supply to the payloads.
13. The CMDS as claimed in claim-1 is capable of operating in three modes

(a) Operational mode for normal firing during mission
(b) Maintenance mode for fault diagnosis during maintenance
(c) Training mode for training pilot without actual firing
14. The CMDS as claimed in claim-1 while in operational mode is capable of
functioning in three modes
(a) Manual mode where the program selection and execution is from pilot
(b) Auto mode where program selection and execution is slaved to RWR/SPJ without pilot intervention
(c) Semi auto where program selection is from RWR and execution is from pilot command
15. The CMDS as claimed in claim-1 is capable of disabling the firing on ground
with safety interlock through Weight On Wheel switch, Aircraft speed switch
and safety switch
16. The CMDS as claimed in claim-1 is capable of providing user defined critical quantity value for chaff and flare and is capable of stopping the firing on reaching critical quantity with warning to the pilot.
17. The CMDS as claimed in claim-1 is capable of providing stop firing command from panel.

18. The CMDS as claimed in claim-1 is provided with '0' Level tester, capable of
testing the CMDS ( monitoring and verifying the fire pulse) in the field and in
the Lab.
19. The CMDS as claimed in claim 1 provided with Data Field Loader is capable of
configuring fire program as per user requirements and provides temporary
storage of the fire program data before transferring the data to the CMDS on
the field.
20. The CMDS as claimed in claim 1 to 19 substantially as herein described with
reference to and as shown in Fig. 1.