Patent Publication Number: US-2007119328-A1

Title: Cartridge ejection and data acquisition system

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The principles of several embodiments of the present invention generally related to an electromechanical system, and more specifically to an electromechanical cartridge ejection and data acquisition system.  
      2. Discussion of the Related Art  
      When applying agricultural chemicals such as pesticides, herbicides, fertilizers, etc., to a target area (e.g., a predetermined agricultural field) via aerial application, it is generally desirable to maximize the amount of agricultural chemical that reaches the target while minimizing the amount of chemical that is applied to non-target areas (e.g., neighboring agricultural fields, schools, residential areas, business areas, etc.). As all aerially applied agricultural chemicals are capable of drifting, it is important to take practice aerial application techniques that help to minimize or prevent drift over non-target areas. Indeed, companies and individuals in the agricultural chemical application industry face the increasing possibility of litigation due to chemical drift as schools, residential areas, and the like, continue to encroach upon agricultural fields.  
      Without accurate information related to meteorological conditions existing at different altitudes over and within the vicinity of the target area (i.e., localized meteorological conditions) such as humidity, temperature, barometric pressure, wind speed and direction, an aerial applicator cannot be sure whether it is safe to apply agricultural chemicals. For example, it is generally ineffective, and often illegal, to aerially apply agricultural chemicals in the presence of wind speeds that are greater than  10  MPH as the agricultural chemicals drift excessively outside the target area. Additionally, agricultural chemicals may drift excessively as aerosols in an atmosphere having a low humidity or high temperature, rather than condense into droplets that precipitate more readily in an atmosphere having a high humidity or low temperature.  
      In the past, smoke has been used to indicate localized meteorological conditions such as wind direction and speed, wherein the smoke is generated by placing a tire in the target area, dousing the tire with kerosene, and burning the tire. Such a solution, however, generates toxic fumes that are often as environmentally unfriendly as the agricultural chemicals are when applied to non-target areas. To avoid burning tires, it has been proposed to equip aircraft with instrumentation that generates navigational information (e.g., information indicating latitude and longitude of the aircraft) and that determines the meteorological conditions within the vicinity of the aircraft. Meteorological conditions vary at different altitudes over the ground. Accordingly, solutions relying solely on aircraft mounted instrumentation cannot determine meteorological conditions existing between the flight path of the aircraft and the surface of the target area (i.e., localized surface meteorological conditions).  
      Without the knowledge of meteorological conditions as they exist at all altitudes over and within the vicinity of the target area, however, aerial applicator pilots essentially estimate the probability that agricultural chemicals will excessively drift onto non-target areas if released from the aircraft at particular altitudes and adjust their flight path to compensate for the probability of drift. Aerial applicator pilots, however, may sometimes estimate incorrectly, resulting in contamination or destruction of crops and significant health risks to people in non-target areas. It was recognition of these and other facts that created the impetus for the development of principles associated with several embodiments of the present invention.  
     SUMMARY OF THE INVENTION  
      Several embodiments of the invention advantageously address the needs above as well as other needs by providing a cartridge, a cartridge ejection unit, and an ejection system and related methods. In one embodiment, an end cap of a smoke cartridge includes a nozzle adapted to be coupled to the end of a smoke cartridge; an aperture defined within a first surface of the nozzle; and a channel extending tortuously through the nozzle, the channel being in fluid communication with the aperture and the interior of the smoke cartridge.  
      In another embodiment, a smoke cartridge includes a first tube; a nozzle coupled to the first tube, the nozzle having a channel extending tortuously therethrough and an aperture in fluid communication with the channel; a pressure-sensitive activation unit fixed inside the first tube and coaxially aligned with the aperture; and a smoke capsule inside the first tube and in fluid communication with the channel.  
      In another embodiment, a cartridge ejection unit includes a magazine housing adapted to contain a plurality of cartridges; an actuator unit coupled to the magazine housing and adapted to exert a force on a cartridge contained within the magazine housing and eject the cartridge from the magazine housing; a cartridge moving unit coupled to the magazine housing and adapted to align the plurality of cartridges with the actuator unit; and an alignment block coupled to an end portion of the magazine housing and adapted to orient a cartridge aligned with the actuator unit.  
      In another embodiment, an ejection system includes a frame; a controller unit coupled to the frame and adapted to receive a command input; a cartridge ejection unit coupled to the frame and adapted to eject a cartridge in response to the received command input; and a recording unit coupled to the controller unit and adapted to record data when the cartridge is ejected.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The above and other aspects, features and advantages of several embodiments of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings.  
       FIG. 1  illustrates a functional block diagram of a cartridge ejection and data acquisition system according to several embodiments of the present invention.  
       FIG. 2  illustrates an exemplary message structure employed in accordance with principles of several embodiments of the present invention.  
       FIG. 3  illustrates a functional block diagram of a controller subsystem according to one embodiment of the present invention.  
       FIG. 4  illustrates a functional block diagram of a remote interface module subsystem according to one embodiment of the present invention.  
       FIG. 5  illustrates a functional block diagram of a cartridge subsystem according to one embodiment of the present invention.  
       FIG. 6  illustrates a functional block diagram of a meteorological subsystem according to one embodiment of the present invention.  
       FIG. 7  illustrates a functional block diagram of a recording subsystem according to one embodiment of the present invention.  
       FIG. 8  illustrates a functional block diagram of a digital video recording unit according to one embodiment of the present invention.  
       FIG. 9  illustrates a functional block diagram of a video overlay unit according to one embodiment of the present invention.  
       FIG. 10  illustrates a functional block diagram of a power subsystem according to one embodiment of the present invention.  
       FIG. 11  illustrates a block diagram of a pre-flight diagnostic according to one embodiment of the present invention.  
       FIG. 12  illustrates a block diagram of an in-flight ejection protocol according to one embodiment of the present invention.  
       FIG. 13  illustrates a block diagram of an in-flight recording protocol according to one embodiment of the present invention.  
       FIG. 14  illustrates a block diagram of a post-flight upload protocol according to one embodiment of the present invention.  
       FIG. 15  illustrates a piping and instrument diagram of a cartridge ejection unit according to one embodiment of the present invention.  
       FIG. 16  illustrates an exterior perspective view of a pod according to one embodiment of the present invention.  
       FIG. 17A  illustrates a first interior perspective view of the pod shown in  FIG. 16  including a cooling assembly in accordance with one embodiment of the present invention.  
       FIG. 17B  illustrates an interior perspective view of the pod shown in  FIG. 16  including a cooling assembly in accordance with another embodiment of the present invention.  
       FIG. 18  illustrates a second interior perspective view of the pod shown in  FIG. 16 .  
       FIG. 19  illustrates a perspective view of a cartridge retainment unit according to one embodiment of the present invention.  
       FIG. 20  illustrates a bottom view of the cartridge retainment unit shown in  FIG. 19 .  
       FIG. 21  illustrates a perspective view of a cartridge according to one embodiment of the present invention.  
       FIG. 22  illustrates a cross-sectional view of the cartridge shown in  FIG. 21  along line I-I′.  
       FIGS. 23 and 24  illustrate an ignition assistor in accordance with various embodiments of the present invention. 
    
    
      Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.  
     DETAILED DESCRIPTION  
      The following description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of exemplary embodiments. The scope of the invention should be determined with reference to the claims.  
      According to principles of several embodiments of the present invention, a cartridge ejection and data acquisition system facilitates the collection of information related to localized surface meteorological conditions and recordation of navigational data and other meteorological data.  
       FIG. 1  illustrates a functional block diagram of a cartridge ejection and data acquisition system according to several embodiments of the present invention.  
      Referring to  FIG. 1 , the cartridge ejection and data acquisition system  100  (herein referred to as the “system”) includes a controller subsystem  110 , a remote interface subsystem  120 , a cartridge subsystem  130 , a navigation subsystem  140 , a meteorological subsystem  150 , a recording subsystem  160 , a power subsystem  170 , and, optionally, one or more auxiliary subsystems  180 . The remote interface subsystem  120  includes a user display  122  coupled to the controller subsystem  110  via a user display interface  124 . The cartridge subsystem  130  includes a cartridge ejection unit  132  comprised of an actuator unit  134  coupled to a cartridge retainment unit  136 . The recording subsystem  160  is further coupled to a video source  101  (e.g., a digital video camera) and, as will be discussed in greater detail below, includes a digital video recording (DVR) unit  162  coupled to a video overlay (VOB) unit  164 .  
      In embodiments where the system  100  is implemented in conjunction with an aerial agricultural chemical applicator (e.g., spray device  103 ), a spray subsystem  190  can be coupled to the controller subsystem  110 .  
      As illustrated, each of the aforementioned subsystems  120  to  190  are coupled to the controller unit  110  such that the subsystems can transmit messages to each other via an instrumentation bus  105  (e.g., wired, wireless, or a combination thereof). Moreover, the power subsystem  170  is coupled to the controller, cartridge, navigation, meteorological, recording, and auxiliary subsystems  110 ,  130 ,  140 ,  150 ,  160 , and  180 , respectively, via an instrumentation power bus  107 .  
      The controller subsystem  110  controls and coordinates the operations of the other subsystems. The remote interface subsystem  120  provides an interface enabling a user to command the system  100  to perform various actions as well as provides a means for displaying the status of the system  100  and various subsystems. The cartridge subsystem  130  provides an interface that controls the ejection of cartridges from the cartridge ejection unit  132 , monitors the status of the actuator unit  134 , and determines how many cartridges remain within the cartridge retainment unit  136 . The navigation subsystem  140  collects navigational telemetry data associated with the system  100  such as latitude, longitude, current time, current date, horizontal speed, and, optionally, vertical speed and/or altitude and transmits the aforementioned navigational telemetry data (e.g., every 1000 milliseconds) to the controller subsystem  110 . The meteorological subsystem  150  collects meteorological telemetry data associated with local meteorological conditions within the vicinity of the system  100  such as air temperature, barometric pressure, humidity, and, optionally, air speed and transmits the aforementioned meteorological telemetry data (e.g., every 1000 milliseconds) to the controller subsystem  110 . In one embodiment, the controller subsystem  110  acquires the collected navigational and meteorological telemetry data (collectively referred to herein simply as “telemetry data”). The recording subsystem  160  records video data associated with video segments generated by a video source  101  and telemetry data acquired by the controller subsystem  110  and is adapted to transmit the recorded video and telemetry data. In one embodiment, the recording subsystem  160  is adapted to overlay video data with the telemetry data acquired by the controller subsystem  110 . The power subsystem  170  provides power voltages necessary to operate the various aforementioned subsystems  110  to  160  and  180 . One or more auxiliary subsystems  180  can be provided to add functionality not otherwise provided by the system  100 .  
      In embodiments where the system  100  is implemented in conjunction with an aerial agricultural chemical applicator the spray subsystem  190  transmits status information regarding the spray device  103  to the controller unit  110 .  
       FIG. 2  illustrates an exemplary message structure employed in accordance with principles of several embodiments of the present invention.  
      Referring to  FIG. 2 , messages transmitted over the instrumentation bus  105  contain framing and addressing information, source and destination addresses, message length, payload, and integrity check data. As shown, each message includes, for example, start of header (SOH) data  202  and a check byte (CHK)  204  that, together provide message framing, a source address (Src)  206  identifying the subsystem sending the message, a destination address (Dst)  208  identifying subsystem to which the message is intended (i.e., the recipient subsystem), a message length identifier (Len)  210  identifying the length of the payload, a payload portion  212  containing the information to be acted upon by the recipient subsystem, and integrity check portion (CRC)  214 . In one embodiment, each recipient subsystem responds to the transmitted message within a predetermined amount of time. In one embodiment, a recipient subsystem responds by transmitting reply message indicating: 1) that the transmitted message was received properly and can be acted upon; 2) that the transmitted message was not received properly and should be retransmitted; or 3) the transmitted message was properly received but the payload is invalid.  
      The controller subsystem  110  is adapted to transmit messages to the remote interface subsystem  120 , the cartridge subsystem  130 , the recording subsystem  160 , and any auxiliary subsystems  180  via the instrumentation bus  105 . As will be discussed in greater detail below, the controller subsystem  110  is further adapted to receive messages transmitted by the aforementioned remote interface, cartridge, navigation, meteorological, recording, and auxiliary subsystems  120 ,  130 ,  140 ,  150 ,  160 , and  180 , respectively, via the instrumentation bus  105 .  
      In one embodiment, the controller subsystem  110  transmits Reset Request messages to any of the aforementioned subsystems, requesting that the recipient subsystem reset itself.  
      In one embodiment, the controller subsystem  110  transmits Status Request messages to any of the aforementioned subsystems, requesting that the recipient subsystem transmit a Status Reply message indicating the health of the recipient subsystem. In one embodiment, Status Request messages are periodically transmitted to the remote interface subsystem  120  (e.g., every 100 milliseconds) and to the cartridge and recording subsystems  130  and  160  (e.g., every 1000 milliseconds).  
      In one embodiment, messages transmitted by the controller subsystem  110  to the remote interface subsystem  120  include remote interface display messages, instructing the user display interface  124  drive the user display  122  to display information associated with a predetermined button according a predefined attribute. Accordingly, remote interface display messages indicate the resolution to which the information is to be displayed, the size with which the information is to be displayed (e.g., small or large), a blink rate with which the information is to be displayed (e.g., none, 1 second, ¼ second, etc.), a color which the predetermined button is to be backlit with (e.g., green, orange, red, etc.), and the particular button with which the information to be displayed is associated (e.g., video button, drop button, system button, etc.).  
      In one embodiment, messages transmitted by the controller subsystem  110  to the cartridge subsystem  130  include an eject command message instructing the actuator unit  134  to eject a cartridge from a predetermined cartridge retainment unit  136 . In one embodiment, the eject command message is transmitted upon receiving a drop request message from the remote interface subsystem  120 .  
      In one embodiment, messages transmitted by the controller subsystem  110  to the digital video recording unit (DVR)  162  includes a DVR Start Video message, instructing the DVR unit  162  to begin recording video data; a DVR Start Telemetry message, instructing the DVR unit  162  to begin recording telemetry data; a DVR Stop Telemetry message, instructing the DVR unit  162  to stop recording telemetry data; a DVR Shutdown message, instructing the DVR unit  162  to shut down; and a Telemetry message containing telemetry data acquired by the controller subsystem  110 . In one embodiment, the Telemetry message is periodically transmitted to the DVR and VOB units  162  and  164  (e.g., every 1000 milliseconds). In one embodiment, the DVR Start Video and DVR Start Telemetry message are transmitted upon receiving a video request message from the remote interface subsystem  120 .  
      Telemetry data contained within the Telemetry message includes, for example, system status/information flag (e.g., video data recording, cartridge ejected, sprayer on, altitude calculated from GPS, auxiliary I/O status, GPS altitude is negative, vertical speed is negative, south latitude, east longitude, etc.), current time (e.g., transmitted as SSMMHH), current date (e.g., transmitted as MMDDYY), longitude, fractional longitude, latitude, fractional latitude, GPS lock status (e.g., none, 2D, 3D, etc.), vertical speed in meters/second (e.g., transmitted as binary value XXXX with an implied decimal point between third and fourth digits), horizontal speed in knots (e.g., transmitted as binary value XXXX with an implied decimal point between third and fourth digits), course (e.g., transmitted as binary value XXXX with an implied decimal point between third and fourth digits), barometric pressure in millibars (e.g., transmitted as binary value XXXXX with an implied decimal point between fourth and fifth digits), temperature in degrees Centigrade (e.g., transmitted as binary value XXXX with an implied decimal point between third and fourth digits), external voltage in tenths of volts (e.g., transmitted as binary value XX with an implied decimal point between the digits), horizontal dilution of precision in tenths (e.g., transmitted as binary value XXX with an implied decimal point between second and third digits), horizontal dilution of precision in tenths (e.g., transmitted as binary value XXX with an implied decimal point between second and third digits), GPS quality indication (e.g., no lock, non-differential GPS lock, differential GPS lock, estimated GPS lock, etc.), GPS altitude in tenths of meters, humidity in tenths of percent, and altitude.  
      In one embodiment, the Telemetry message further contains attribute information instructing the VOB unit  164  to overlay the aforementioned telemetry data with the video data in accordance with predetermined row, column, color, and display attributes. For example, the attribute information instructs the overlay unit  164  to overlay data representing latitude in a manner such that it is displayed as XXXYY.ZZZZZA (where XXX is degrees, YY is minutes, ZZZZZ is fractional minute, and A is the N/S indication), data representing longitude in a manner such that it is displayed as XXXYY.ZZZZZA (where XXX is degrees, YY is minutes, ZZZZZ is fractional minute, and A is the E/W indication), data representing current time in a manner such that it is displayed as HHMMSS (where HH is hour, MM is minute, and SS is second), data representing current date in a manner such that it is displayed as MMDDYY (where MM is month, DD is day, and YY is year), data representing horizontal speed in a manner such that it is displayed as XXX.X knots, data representing air speed in a manner such that it is displayed as XXX mph, data representing altitude in a manner such that it is displayed as XXXXX feet in normal video if altitude is computed from barometric pressure or as XXXXX feet in reverse video if altitude is obtained via the navigational subsystem  140 , data representing lock type in a manner such that it is displayed as XX (where XX is NO, 2D, 3D, or ??—representing no lock, 2D, 3D, or unknown, respectively), data representing humidity in a manner such that it is displayed as XXX % (where XXX is the relative humidity in percent). In another embodiment, the overlay messages instruct the overlay unit  164  to overlay data representing a video file indicator in a manner such that it is displayed as XX or blank (where XX indicates that the video recording is in progress and blank indicates that video recording is not in progress) and data representing a cartridge event tag in a manner such that it is displayed as XX in normal video or blank if a cartridge was successfully ejected and displayed as XX in reverse video if a cartridge was unsuccessfully ejected (where XX indicates the cartridge number).  
      In one embodiment, messages transmitted by the remote interface subsystem  120  to the controller subsystem  110  include the aforementioned video request and drop request messages in addition to system request message.  
      The cartridge subsystem  130  is adapted respond to the eject command message by ejecting a cartridge and transmitting reply message indicating that a cartridge was executed (e.g., because a next available cartridge was ejected from within a particular cartridge retainment unit  136  or because a cartridge ejected from within a particular cartridge retainment unit  136  was not the next available cartridge), that a cartridge was not ejected (e.g., because no cartridge retainment unit  136  contains cartridges), or that a cartridge was not ejected due to insufficient power applied to the actuator unit  134  or because cartridge ejection unit  132  is otherwise prevented from ejecting cartridges.  
      As mentioned above, the controller subsystem  110  is adapted to coordinate operations of the aforementioned remote interface, cartridge, recording, navigation, meteorological, and auxiliary subsystems  120 ,  130 ,  140 ,  150 ,  160 , and  180 , respectively.  
      Accordingly, and with reference to  FIG. 3 , the controller subsystem  110  includes one or more embedded processing units (MPU)  302 , an external flash memory  304 , a global positioning system (GPS) unit  306 , a network interface  308 , a plurality of (e.g., three) digital expansion connectors  310 , an analog expansion connector  312 , a digital I/O port  320 , at least one configuration port  322 , and a subsystem interface  324 .  
      In one embodiment, the MPU  302  is based on various PC-104 standards and has 128 Kbytes of main memory, 3840 bytes SRAM, and 1024 bytes EEROM, 2 hardware URTs, and a plurality of (e.g., 52) I/O lines. In one embodiment, the external flash memory  304  is provided as to Atmel AT41DB041 4 mbit Data Flash Memories for a total of 1 mbytes of non-volatile memory. In one embodiment, the navigational subsystem  140  is physically embodied as the GPS unit  306  (e.g., provided as a Garmin GPS-15 module, GPSFlight GPSF-UBLOX GPS module, or the like, or combinations thereof). In another embodiment, however, the navigational subsystem  140  is physically embodied as any suitable device or array of devices that are electrically connected to the controller subsystem  110  (e.g., from within an aircraft). In one embodiment, the network interface  308  is provided as a radio modem capable of communicating over a desired network (e.g., BlueTooth, HomeRF, IEEE 802.11x, 802.20, and its successors or cellular wireless networks, etc.). In one embodiment, digital expansion connectors  310  are used to support any digital sensors within the navigational or meteorological subsystems  140  or  150 . Likewise, analog expansion connectors  312  are used to support any analog sensors within the navigational or meteorological subsystems  140  or  150 .  
      In one embodiment, the configuration port  322  is provided as a shared RS-232 port. In another embodiment, commands received via the configuration port  322  to configure the network interface  308  and the GPS unit  306 . In another embodiment, the controller subsystem  110  communicates directly with the DVR unit  162  via the configuration port  322 .  
      In one embodiment, the subsystem interface  324  is provided as a multidrop RS-485 link. In another embodiment, the remote interface and cartridge subsystems  120  and  130 , in addition to the VOB unit  164 , communicate with the controller subsystem  110  via the power subsystem  170  using the subsystem interface  324 .  
      As mentioned above, the remote interface subsystem  120  provides a user interface for the system  100  and includes a user display  122  coupled to a user display interface  124 . In one embodiment, and with reference to  FIG. 4 , the remote interface subsystem  120  includes the aforementioned user display  122  and user display interface  124  provided within an enclosure  402 . In one embodiment, the user display  122  includes video, drop, and system buttons  404 ,  406 , and  408 . The user display interface  124  includes a printed circuit board (PCB)  410  supporting a processor  412  and a controller interface component  414  that facilitates communication between the processor  412  and the controller unit  110  via the aforementioned subsystem interface  324 .  
      When actuated by a user, the video, drop, and system buttons  404 ,  406 , and  408 , respectively, close a circuit within the user display interface  124  that is configured to transmit the aforementioned video, drop, and system request messages, respectively, to the controller subsystem  110 . In one embodiment, the video, drop, and system buttons  404 ,  406 , and  408  are provided as pushbuttons, each coupled to a backlit light crystal display (LCD) (e.g., a 36×24 LCD). In one embodiment, the user display interface  124  is adapted to drive the video, drop, and system buttons  404 ,  406 , and  408  in accordance with remote interface display messages transmitted by the controller subsystem  110 . The LCDs of the video, drop, and system buttons  404 ,  406 , and  408  are driven by the processor  412  to display information associated with results of any of the aforementioned video, drop, and system request messages, respectively. Further, each LCD can be backlit in a plurality of colors including, for example, red, green and, optionally, orange (e.g., by multiplexing red and green rapidly) depending on the status of a particular subsystem associated with the button.  
      In an exemplary embodiment, the video button  404  is backlit in green to indicate that the DVR unit  162  is operational but not recording, backlit in red to indicate that the DVR unit  162  is recording, or backlit in flashing red to indicate that there is a fault within the recording subsystem  160 . In one embodiment, when backlit in flashing red, the video button  404  displays a “FAULT” message indicating that a fault in DVR unit  162  has been detected, a “NO CAM” message indicating that no video source is detected by the VOB unit  164 , and a “NO VIDEO” message indicating that no video source is detected by the DVR unit  162 .  
      In an exemplary embodiment, the drop button  406  is backlight in green to indicate that the cartridge ejection unit  132  is disarmed and, therefore, cannot eject a cartridge, backlit in red to indicate that the cartridge ejection unit  132  is armed and, therefore, can eject a cartridge, and backlit in flashing red to indicate that there is a fault within the cartridge subsystem  130 . In one embodiment, when backlit in flashing red, the drop button  406  displays a “FAULT” message indicating that a fault in the cartridge subsystem  130  has been detected, a “MAG EMPTY” message indicating that magazines of all cartridge retainment units are empty, a “NO A INDEX” message indicating that a first magazine (e.g., magazine “A”) failed to index to the next cartridge, a “NO B INDEX” message indicating that a second magazine (e.g., magazine “B”) failed to index to the next cartridge. In another embodiment, when backlit in green, the drop button  406  displays the number of cartridges remaining within the cartridge retainment unit  136 .  
      In an exemplary embodiment, the system button  408  is backlit in green to indicate that the system  100  is operational, all subsystems are operational, the GPS unit  206  has a  3 D lock, and the user has calibrated (e.g., zeroed) the barometric pressure, is backlit in orange to indicate that the CPS unit  206  has a 2D lock, is backlit in red to indicate that the CPS unit  206  has no lock or the that the barometric pressure has not been calibrated. In another embodiment, the system button  408  displays the air temperature and relative humidity when backlight in green and orange. In another embodiment, when backlit in red, the system button  408  displays a “ZERO BP?” message when the barometric pressure can be calibrated and displays a “NO LOCK” message when the barometric pressure has been calibrated and the GPS unit  206  does not have a lock. In another embodiment, when backlit in flashing red, the system button  408  displays a “FAN SPEED” message indicating the fan speed within the system is below minimum, a “FAULT” message indicating a fault has been detected within the system  100 , a “INVAL HUM” message indicating an invalid humidity reading, a “LOW VOLT” message indicating the system voltage is below a minimum, a “NO DVR” message indicating the DVR unit  162  is inoperative, a “NO MAG” message indicating cartridge retainment unit is present, a “NO PRESS” message indicating the actuator system  132  is not pressurized, a “NO AIRSPD” message indicating that a sensor within meteorological subsystem  150  is not sensing air speed, a “NO BAROM” message indicating that a sensor within meteorological subsystem  150  is not sensing barometric pressure, a “NO HUM” message indicating that a sensor within meteorological subsystem  150  is not sensing humidity, a “NO BTEMP” message indicating inability to sense temperature from barometric pressure sensor, a “NO HTEMP” message indicating inability to sense temperature from humidity sensor, a “OVER TEMP” message indicating a high temperature from the meteorological subsystem  150 , in addition to any of the displayed messages associated with the video and drop buttons.  
      As mentioned above, the cartridge subsystem  130  provides an interface that controls the ejection of cartridges from the cartridge ejection unit  132 , monitors the status of the actuator unit  134 , and determines how many cartridges remain within a particular cartridge retainment unit  136 . Accordingly, and in one embodiment exemplarily illustrated in  FIG. 5 , the cartridge subsystem  130  includes a processor PCB  502  and at least one sensor PCB  504 . In an exemplary embodiment, the processor PCB  502  supports a processor  506 , controller interface component  508  adapted to communicate to the controller unit  110  via the aforementioned subsystem interface  324 , and at least one sensor interface component  510  adapted to facilitate communication between the processor  506  and a corresponding sensor PCB  504 . In an exemplary embodiment, each sensor PCB  504  supports sensor circuitry  518  adapted to detect characteristics associated with a cartridge retainment unit  136  operably proximate thereto within the cartridge ejection unit  132  and transmit messages corresponding the detected characteristics to the processor  506  via a corresponding sensor interface component  510 .  
      In embodiments where the actuator unit  134  is implemented as a pneumatically operated actuator unit, the processor PCB  502  supports components adapted to receive, as an input, a message indicating that the air pressure within the actuator unit  134  is OK (e.g., via a voltage from a pressure switch sensed through a first optical isolation circuit  512 ). In embodiments where the actuator unit  134  is implemented as an electrically controlled, pneumatically operated actuator unit, the processor PCB  502  further supports components adapted to output actuation power (e.g., 12 VDC) to operate the actuator unit  134 .  
      In embodiments where the system  100  is implemented in conjunction with the aerial agricultural chemical applicator, the processor PCB  502  supports components adapted to receive, as inputs, a message indicating that the aircraft ignition switch is on (e.g., via a voltage from an aircraft ignition switch sensed through a second optical isolation circuit  514 ) and that the spray device  103  is on (e.g., via a voltage from a spray system switch sensed through a third optical isolation circuit  516 ).  
      In another embodiment the processor PCB  502  may also support components adapted to receive, as inputs, data representing a fan tachometer and differential air pressure to compute air speed (e.g., via a voltage from a dynamic pressure sensor  520 ).  
      In one embodiment, the sensor circuitry  518  supported by a sensor PCB  504  includes Hall Effect sensors adapted to detect magnetic fluctuations within a cartridge retainment unit  136  adjacent thereto that indicate, for example, the number of cartridges remaining therein, whether the remaining cartridges are properly indexed after an ejection event, etc.  
      As mentioned above, the meteorological subsystem  150  collects meteorological telemetry data associated with meteorological conditions within the vicinity of the system  100  such as air temperature, barometric pressure, humidity, and, optionally, air speed. Referring to  FIG. 6 , the meteorological subsystem  150  is physically embodied as a sensor array  600  including, for example, an air temperature sensor  602 , a barometric pressure sensor  604 , a humidity sensor  606 , and an airspeed sensor  608 . In one embodiment any of the aforementioned sensors may be digital or analog. Where the sensors are analog the aforementioned analog expansion connector  312  is connected between the analog sensor and the controller subsystem  110 . In one embodiment, the analog expansion connector includes a multiplexer  610  coupled to the analog sensor(s) and an analog-to-digital (A/D) converter  612  coupled between the multiplexer and the embedded processing unit  302  of the controller subsystem  110 . The sampling rates of the multiplexer  610  and A/D converter  612  may be optimized to allow for collection of sufficient digital information without exceeding the processing capabilities and/or storage capacities of the embedded processing unit  302  of the controller subsystem  110 .  
      As mentioned above, the recording subsystem  160  records video data associated with video segments generated by a video source  101 , recording telemetry data acquired by the controller subsystem  110 , transmitting the recorded video and telemetry data, and overlaying the video data with the telemetry data acquired by the controller subsystem  110 . Accordingly, and with reference to  FIG. 7 , the recording subsystem  160  includes a digital video recording unit (DVR)  162  and a video overlay (VOB) unit  164 , wherein the DVR unit  162  coupled to the input of the video source  101  and wherein the VOB unit  164  is coupled to the output of the video source  101 .  
      Referring now to  FIG. 8 , the DVR unit  162  includes a DVR main board portion  810 , a frame grabber portion  820 , and a network portion  830 . In one embodiment, the DVR main board portion  810  and the frame grabber portion  820  communicate to each other via a PC-104 interface  802  as do the frame grabber portion  820  and the network portion  830 .  
      The DVR main board portion  810  includes a processor  812 , a first (e.g., serial) I/O link  814  to the controller subsystem  110  coupled to the processor  812 , a second (e.g., digital) I/O link  815  coupled to an input of the video source  101  and the processor  812 , and a storage device interface  816  coupled between a storage device  817  (e.g., an IDE storage device) and the processor  812 . In one embodiment, the processor  812  is adapted to output a video source command signal (e.g., a TTL signal) turning the video source  101  on in response to a DVR Start Video message transmitted by the controller subsystem  110  and received via the first I/O link  812 .  
      The frame grabber portion  820  is adapted to receive a composite video signal from the VOB unit  164  (e.g., an NTSC video signal generated by the video source  101  and overlaid with data contained within the Telemetry message) and forward the received composite video signal to the DVR main board portion  810 . In one embodiment, the processor  812  is adapted to receive data contained within the Telemetry message transmitted by the controller subsystem  110  via the first I/O link  812 , in addition to data within a composite video signal stream provided by the frame grabber portion  820  via the PC-104 interface  802 , and store the received data in the storage device  817  (e.g., in an MPEG4 format) via the storage interface  816 . In one embodiment, data is stored within the storage device  817  for until a predetermined amount of time has elapsed from receipt of the DVR Start Video message. In another embodiment, data within a single composite video stream is stored as a separate file within the storage device  817 .  
      The network portion  830  is provided as a network card (e.g., an IEEE 802.11b network card) adapted to transmit data stored within the storage device  817  to a base station (not shown) via, for example, an FTP protocol over a wireless link. In one embodiment, the network portion  830  transmits the stored data to the base station periodically or when one or more predetermined conditions are met. Once the data is transmitted, the storage device  817  may be purged of data and be prepared to store new data sets.  
      In one embodiment, the base station includes a processor (e.g., a Windows-based PC), a serial Modem enabling communication over standard phone lines, and a network access point (e.g., Ethernet WiFi). Due to certain federal regulations, the DVR subsystem  160  is configured to transmit the system data only when, for example, the DVR subsystem  160  is on the ground. Accordingly, the DVR subsystem  160  can be configured to automatically transmit the system data when a value of a portion of the sensor data (e.g., altitude, barometric pressure, groundspeed, air temperature, or the like, or combinations thereof) is greater than or less than a predetermined value or through a user-initiated command via the controller subsystem  110 .  
      Referring to  FIG. 9 , the VOB unit  164  includes a PCB  902  supporting a processor  904 , a basic overlay board (BOB)  906 , and support components including, for example, a video input  908 , a video output  910 , and a controller interface component  912 . In one embodiment, the BOB  906  is adapted to accept video signals (e.g., NTSC) from the video source  101  having been turned on by the video source command signal output by the DVR main board portion  810 , insert data contained within the Telemetry message transmitted by the controller subsystem  110  in a textual format specified by the Overlay Attribute message also transmitted by the controller  110 , thereby forming a composite video signal, and output the composite video signal to the frame grabber portion  820 .  
      As mentioned above, the power subsystem  170  provides power to the system  100 . In one embodiment, the power provided by the power subsystem  170  is distributed to the cartridge, navigation, meteorological, and recording subsystems  130 ,  140 ,  150 , and  160 , respectively, in accordance with instructions output by the controller subsystem  110 . Accordingly, and with reference to  FIG. 10 , the power subsystem  170  includes a first voltage regulator (VR 1 )  1002  coupled to an external power source, an internal battery  1004  coupled to the first VR  1002 , second and third VRs  1006  and  1008 , respectively, coupled to the internal battery  1004 , a voltage divider  1010  coupled between the internal battery  1004  and the controller subsystem  110 , a relay  1012  coupled between the internal battery  1004 , the controller subsystem  110 , and fourth, fifth and sixth VRs  1014 ,  1016 , and  1018 , respectively.  
      The first VR  1002  receives an input power having a first voltage (e.g., 28 VDC), steps down the input power to a second voltage sufficient to charge the internal battery  1004  (e.g., 13.8 VDC), and outputs the second voltage to the internal battery  1004 . In one embodiment, the second voltage is selected using a 3 to 5 A with the GND terminal floated above ground using a resistor having a predetermined value.  
      The second and third VRs  1006  and  1008  receive the second voltage from the internal battery  1004  and output third and fourth voltages (e.g., 12 VDC and 5 VDC, respectively) to the instrumentation power bus  107  circuit and the controller subsystem  110 , respectively. The controller subsystem  110  monitors the voltage of the internal battery  1004  via an external voltage (Vext) output by voltage divider  1010 . In one embodiment, the voltage divider includes 90.9 Kohm and 60.4 Kohm resistors and provides a monitoring voltage range of 0 to 15.3 volts.  
      The relay  1012  includes a FET circuit and switches the second voltage to the fourth to sixth VRs  1014  to  1018 . Upon receipt of the switched second voltage, the fourth and fifth VRs  1014  and  1016  output fourth and fifth voltages (e.g., 5 VDC and 12 VDC) to the DVR unit  162  and the sixth VR  1018  outputs a sixth voltage (e.g., 12 VDC) to the instrumentation power bus  107 .  
      Having described the functional characteristics of, and interrelationships between the various aforementioned subsystems, a discussion of their cooperative operation will now be described with reference to FIGS.  11  to  14 .  
      In embodiments where the system  100  is implemented in conjunction with an aerial agricultural chemical applicator (e.g., spray device  103 ), the system  100  undergoes a pre-flight diagnostic  1100  described with respect to  FIG. 11 , wherein the system  100  receives its operating power via the power system of the aircraft (step  1102 ). Upon receiving the operating power, the controller subsystem  110  outputs a message instructing the power subsystem  170  to provide power to the DVR unit  162  and the instrumentation power bus  107  (step  1104 ). When the controller subsystem  110  determines that the aircraft&#39;s ignition is on, the controller subsystem  110  transmits a message to the DVR unit  162 , instructing it to disable the network portion  830  (step  1106 ).  
      The controller subsystem  110  then transmits Status Request messages and acquires Status Reply messages from, for example, the cartridge and recording subsystems  130  and  160  (step  1108 ). If any of the aforementioned subsystems report the presence of a fault, the remote interface subsystem  120  displays, via the aforementioned video, drop, and system buttons  404 ,  406 , and  408 , the reported fault conditions (step  1110 ). In one embodiment, the user can acknowledge/clear the reported fault conditions by pressing the particular video, drop, or system button(s) on which the fault information is displayed (step  1112 ). If Status Reply messages by the cartridge and recording subsystems  130  and  160  indicate proper operation, the system button  408 , for example, is driven to indicate that the barometric pressure can be calibrated (step  1114 ). Thus, when a user presses the system button  408 , the controller subsystem  110  instructs a barometric pressure sensor  604  to undergo a calibration process. In one embodiment, the GPS unit  306  automatically attempts to acquire satellites via a 2D or 3D lock (step  1116 ). Accordingly, the system button  408  is driven accordingly during satellite acquisition. Subsequently, the system  100  is ready for in-flight operation (step  1118 ).  
      According to principles of several embodiments of the present invention, cartridges can be ejected onto a target area during flight according to an ejection protocol  1200  described with respect to  FIG. 12 . In one embodiment, the cartridge is provided as a smoke cartridge that indicates localized surface meteorological conditions (e.g., wind direction across the target area surface) that, when ejected, enables a pilot to adjust flight paths in a manner that maximizes spraying over the target area and minimizes spraying or drift in non-target areas.  
      Upon approach to the target area, the drop button  406  is backlit in green, indicating that the cartridge ejection unit  132  is disarmed (step  1202 ). Prior to applying any agricultural chemical to the target area, the user presses the drop button  406  once to arm the cartridge ejection unit  132 , thereby changing the backlight color of the drop button  406  from green to red (step  1204 ). In one embodiment, if the user does not press the drop button  406  within a predetermined amount of time during which it stays backlit in red, the cartridge ejection unit  132  becomes disarmed and the drop button  406  is backlit in green (step  1206 ). If the user presses the drop button  406  within the predetermined amount of time, the smoke cartridge will be ejected (step  1208 ). When a smoke cartridge is ejected successfully, the drop button  406  is backlit in green and the number of cartridges remaining within the cartridge ejection unit  132  is displayed. If a smoke cartridge is unsuccessfully rejected (e.g., because the actuator unit  134  is not sufficiently pressurized, the next cartridge is not properly indexed, etc.), the drop button  406  is backlit in flashing red and a fault message is displayed.  
      Once successfully ejected onto the target area, the smoke cartridge generates a smoke plume that can be recognized by a video source  101  during flight according to a recording protocol  1300  described with respect to  FIG. 13 . Accordingly, and prior to applying the agricultural chemical, the video button  404  is backlit in green, indicating that the DVR unit  162  is operational but not recording (step  1302 ). Upon approaching the target area, just prior to applying any agricultural chemical to the target area, the user presses the video button  404  once to initiate recording by the DVR unit  162 , thereby changing the backlight color of the video button  404  from green to red while the recording is in process (step  1304 ). In one embodiment, recording is initiated when the controller subsystem  110  transmits the DVR Start Video message and the DVR Start Telemetry message to the recording subsystem  160 . The DVR unit  162  terminates recording video automatically after a predetermined amount of time (see step  1306 ) after which the controller subsystem  110  transmits the DVR Stop Telemetry message to stop recording telemetry data (step  1308 ). In one embodiment, the video button  404  displays the name of the video file being recorded. If, for example, the storage device  817  is full, the video button  404  is backlit in flashing red and a fault message is displayed.  
      As mentioned above, the spray subsystem  190  of an aerial applicator can be coupled to the controller subsystem  110  wherein the spray subsystem  190  is adapted to transmit a spray status message to the controller subsystem  110  indicating when the spray device  103  is activated. In one embodiment, data contained within the spray status message is included within the Telemetry message that is overlaid with the video signal generated by the video source  101  by the VOB unit  164  and provides a record of the location in which the agricultural chemical was applied.  
      After the data is recorded and stored within the storage device  817 , it can be transmitted to a base station via the network portion  830  according to a transmission protocol  1400  described with respect to  FIG. 14 . The process begins at step  1402 . In one embodiment, the recorded data is transmitted when one or more predetermined conditions are met (step  1404 ). For example, the recorded data is transmitted when the controller unit  110  determines that the aircraft ignition is off. In another example, the recorded data is transmitted when conditions sensed by the navigational and/or meteorological subsystems  140  and/or  150  (e.g., air temperature, barometric pressure, altitude, air speed, etc.) indicates the aircraft is on the ground.  
      To transmit the recorded data, the controller subsystem  110  instructs the DVR unit  162  to activate the network portion  830  and initiate uploading the recorded data to the base station (step  1406 ). In one embodiment, the controller subsystem  110  transmits a Status Request message to the DVR unit  162  at predetermined intervals to determine whether the uploading is complete (step  1408 ). When the upload operation is complete, the controller subsystem  110  transmits a DVR Shutdown message to the DVR unit  162  (step  1410 ). In one embodiment, the controller subsystem  110  transmits a Status Request message to the DVR unit  162  at predetermined intervals to determine whether the DVR unit  162  has shut down (step  1412 ). After the shutdown has been completed (i.e., when the DVR unit  162  ceases to transmit Status Reply messages) for a predetermined amount of time (e.g., 1 minute), the controller subsystem  110  disables the instrumentation power bus  107  (step  1414 ).  
      In one embodiment, if the controller subsystem  110  determines the external voltage Vext to be below a predetermined level, the controller subsystem  110  transmits the aforementioned DVR Shutdown message to the DVR unit  162 , regardless of the status of the uploading. If the DVR unit  162  cannot shut down in response to the DVR Shutdown message, it responds with a CANCEL response. Accordingly, the controller subsystem  110  periodically transmits the DVR Shutdown message to the DVR unit  162  until the DVR unit  162  ceases to respond.  
      Having described the general functional characteristics of, and interrelationships between the various aforementioned subsystems, and various methods that can be implemented using the same, a detailed discussion will now be provided with respect to physically manifested embodiments of the system  100  and various other subsystems.  
       FIG. 15  illustrates a cartridge ejection unit  132  in accordance with one embodiment of the present invention. In the diagram, electrical interconnections are shown in solid lines while pneumatic interconnections are shown in cross-hatched lines.  
      Referring to  FIG. 15 , the cartridge ejection unit  132  includes an actuator unit  134  and a cartridge retainment unit  136 .  
      In one embodiment, the cartridge retainment unit  136  contains cartridges  1502  which can be individually ejected during operation of the actuator unit  134 . As will be discussed in greater detail below, the cartridges  1502  contain systems adapted to perform substantially any process. Additionally, the cartridges  1502  can be advanced (i.e., indexed) within the cartridge retainment unit  136  along the direction of the arrow to enable sequential ejection of the cartridges  1502 .  
      In the illustrated embodiment, the aforementioned sensor circuitry  518  is arranged proximate to the cartridge retainment unit  136  to detect magnetic fluctuations within the cartridge retainment unit  136  that indicate, for example, the number of cartridges remaining therein, whether the remaining cartridges are properly indexed after an ejection event, etc.  
      In the illustrated embodiment, the actuator unit  134  includes an air compressor  1504   a,  an air pressure switch  1506 , an air reservoir tank  1504   b,  and a cylinder assembly  1507  including a solenoid  1508 , and a cylinder  1510 . The cylinder  1510  includes a single acting spring return mechanism  1512  coupled to an internal piston  1514  which, in turn, is coupled to a striking rod  1516 . Although only one cylinder assembly  1507  and one cartridge retainment unit  136  are illustrated, it will be appreciated that the actuator can include any number of cylinder assemblies  1507  and a corresponding number of cartridge retainment units  136 . For example, the actuator unit  134  may include two (or four) cylinder assemblies  1507  and two (or four) cartridge retainment units  136 .  
      The air compressor  1504   a  provides a primary source of pressurized air which is stored in the air reservoir tank  1504   b  and used to supply pressurized air to the cylinder  1510 . The air pressure switch  1506  activates the air compressor  1504   a  when the air pressure within the actuator unit  134  falls below a first predetermined pressure value and deactivates the air compressor  1504   a  when the air pressure within the actuator unit  134  rises above a second predetermined pressure value. The solenoid  1508  selectively opens and closes the cylinder  1510  to pressurized air provided by the air compressor  1504   a  in response to a signal generated upon a user pressing the aforementioned drop button  406 .  
      According to principles of several embodiments of the present invention, the striking rod  1516  is provided with a tip  1518  configured to contact a pressure-sensitive activation unit (see, for example,  2211  in  FIG. 22 ) of a cartridge  1502  provided in accordance with one embodiment of the present invention and aligned therewith. Air admitted into the cylinder  1510  via the solenoid  1508  forces piston  1514  and striking rod  1516  toward a cartridge  1502  aligned therewith in the cartridge retainment unit  136 . In one embodiment, the tip  1518  of the striking rod  1516  contacts the pressure-sensitive activation unit  2211  of the cartridge  1502  with sufficient force to simultaneously eject the cartridge  1502  from the cartridge retainment unit  136  and to initiate a process (e.g., a chemical reaction) within the cartridge  1502  (i.e., activate the cartridge  1502 ). After one cartridge  1502  is ejected from the cartridge retainment unit  136 , another cartridge is automatically aligned with the tip  1518  of the striking rod  1516 .  
       FIG. 16  illustrates an exterior perspective view of a pod according to one embodiment of the present invention.  
      According to several embodiments of the present invention, and with general reference to FIGS.  16  to  18 , the aforementioned subsystems  110  and  130  to  170  are provided within a pod  1600 . In one embodiment, the remote interface subsystem  120  is located externally to the pod  1600  where it is accessible to the user (e.g., in a cockpit of an aircraft). In another embodiment, the pod  1600  is configured to be mounted onto a surface (e.g., a hard point of an aircraft) such that the cartridges  1502  can be ejected in, for example, a downward direction. Notwithstanding the discussion provided here, it will be appreciated that the pod  1600  can also be mounted onto substantially any desired a surface (e.g., a hard point of a ground vehicle, a stationary structure, etc.).  
      Referring to  FIG. 16 , the pod  1600  includes a frame  1601  formed of a material such as aluminum and having at least one ejection unit support portion  1602  and an interface support portion  1603 . Two ports  1604  are included within the ejection unit support portion  1602 . In one embodiment, each port  1604  is defined by upper (e.g., first) and lower (e.g., second) bracket portions  1605  and  1606 , respectively. In another embodiment, the ports  1604  further include longitudinal sidewall portion (see, for example,  1703  in  FIG. 17A ), and a terminal frontwall portion (see, for example,  1808  in  FIG. 18 ). Also illustrated is a first retainment pin opening  1607  formed within the cartridge retainment unit  136 , a retainment pin  1608  received within the first retainment pin opening  1607 , and a constant force spring  1610  implemented in accordance with an embodiment of the present invention. As also illustrated, the pod  1600  includes first to third cover units  1612   a  to  1612   c,  respectively, forming a covering structure  1611  that defines an interior space where the aforementioned subsystems  110  and  140  to  170  are located. A first opening (e.g., an air intake opening)  1614   a  is defined within the first cover unit  1612   a.  In one embodiment, a plurality of second openings (e.g., air circulation openings)  1614   b  are defined within, for example, the ejection unit support and interface support portions  1602  and  1603  of the frame  1601 .  
      In one embodiment, the first and third cover units  1612   a  and  1612   c,  respectively, are formed of a material such as plastic while the second cover unit  1612   b  is formed of a material such as aluminum. In another embodiment, the second cover unit  1612   b  serves as a structural member of the pod  1600 , wherein the pod  1600  is mounted to the desired surface via the second cover unit  1612   b.    
      In one embodiment, the air circulation openings  1614   b  allow air cleaned by a cooling unit (see, for example,  1710  in  FIG. 17A  or  FIG. 17B ) to circulate through, and exit the interior space defined by the covering structure  1611 , thereby cooling the aforementioned subsystems  110  and  140 - 170 .  
      In one embodiment, the port  1604  of each cartridge ejection unit is adapted to receive and secure a cartridge retainment unit  136 . In another embodiment, the number of cartridge retainment units  136  that can be received and secured by the ejection unit support portion  1602  corresponds to (e.g., is equal to) the number cylinder assemblies  1507  included within the actuator unit  134 . For example, the actuator unit  134  includes two cylinder assemblies  1507  and the ejection unit support portion  1602  includes two ports  1604 .  
      As will be discussed in greater detail below, the cartridge retainment unit  136  is secured within a respective port  1604  upon inserting a retainment pin  1608  into a first retainment pin opening  1607  and a second retainment pin opening (see, for example,  1804  in  FIG. 18 ).  
       FIG. 17A  illustrates a first interior perspective view of the pod shown in  FIG. 16  including a cooling assembly in accordance with one embodiment of the present invention.  
      Referring to  FIG. 17A , the ejection unit support portion  1602  includes a cylinder assembly opening  1701 , a discharge opening  1702 , and the aforementioned longitudinal sidewall portion  1703 . As illustrated, the pod  1600  further includes a processing unit  1704 , a heat-sink  1706 , the aforementioned cooling unit  1710 , a plurality of port guides  1720 , and a cartridge containment unit  1730 . In the illustrated embodiment, the cooling and filtering assembly includes mounting elements  1711 , a fan  1712 , an air intake  1713 , an inlet prefilter  1714 , an air filter  1715 , an air box  1716 , and an air box lid  1717 . Also in the illustrated embodiment, the cartridge containment unit  1730  includes a solenoid  1731 , a plunger  1732 , a spring  1733 , a connection rod  1734  having first and second terminal ends  1735   a  and  1735   b,  a horn  1736 , a gate  1737 , and a pad  1738 . Further, the actuator unit  134  is shown to further include compressor air supply lines  1722  and cylinder air supply lines  1724 .  
      As shown, the aforementioned actuator unit  134  is coupled to an external (e.g., upper) surface of the upper bracket portion  1605  and is concealed, for example, by the second and/or third cover units  1612   b  and/or  1612   c,  respectively. The cylinder assembly opening  1701  is defined within the upper bracket portion  1605  to receive the tip  1518  of striking rod  1516  and allow, as will be discussed in greater detail below, a cartridge  1502  to be ejected from the cartridge retainment unit  136 . The discharge opening  1709  is defined within the lower bracket portion  1606  to receive a cartridge  1502  that has been ejected from the cartridge retainment unit  136  and allow the ejected cartridge  1502  to exit the pod  1600 .  
      The aforementioned subsystems  110  and  140 - 170  (e.g., included within processing unit  1704 ), in addition to the aforementioned sensor assembly  600 , are coupled to the interface support portion  1602  of the frame  1601  that is concealed, for example, by the first cover unit  1612   a.  In one embodiment, the battery  1004  is coupled to the ejection unit support portion  1602 . In the illustrated embodiment, the heat-sink  1706  is coupled to the processing unit  1704  to transfer heat away from the electrical components included therein.  
      As shown, the aforementioned sensor circuitry  518  can be coupled to the longitudinal sidewall portion  1703  such that it is operably proximate to a cartridge retainment unit  136  received within the port  1604 .  
      In one embodiment, the compressor and cylinder air supply lines  1722  and  1724 , respectively, provide the pneumatic interconnections described above with respect to  FIG. 15 . Thus, the compressor air supply lines  1722  connect the air compressor  1504   a  and the air reservoir tank  1504   b  (e.g., via suitable fittings) while each cylinder air supply line  1724  connects the air compressor  1504   a  with a respective cylinder assembly  1507  (e.g., via suitable fittings).  
      According to principles of several embodiments of the present invention, the aforementioned subsystems  110  and  140 - 170  are air cooled via the cooling unit  1710 . In one embodiment, the cooling unit  1710  is provided as an integral unit and may be mounted to the first cover unit  1612   a  via mounting elements  1711  such that the air intake  1713  is aligned with the air intake opening  1614   a  defined within the first cover unit  1612   a.  The fan  1712  is in fluid communication with the air intake  1713  and pulls air from outside the covering structure  1611 , through the first opening  1614   a,  into the air intake  1713 , and into the inlet prefilter  1714  (e.g., a centrifugal filter) where heavy particles (e.g., dirt, oil, aerosols, etc.) are removed from the pulled air. The pre-filtered air then flows through the air box  1716  to the air filter  1715  where fine particles are removed from the air stream and is finally directed through an exhaust opening of the air box lid  1717  where the cleaned air flows around and cools the aforementioned subsystems  110  and  140 - 170  which are, for example. The flow path described above is exemplarily shown in  FIG. 17  at the dashed line  1718 .  
      In another embodiment, and as exemplarily shown in  FIG. 17B , the cooling unit  1710  may consist solely of the aforementioned fan  1712 . In this embodiment, the fan  1712  is mounted to, for example, a region of the interface support portion  1603  between the processing unit  1704  and the air intake opening  1614   a  defined within the first cover unit  1612   a.  In the illustrated embodiment, the aforementioned sensor array  600  may be coupled to a region of the interface support portion  1603  location immediately downstream of the air intake opening  1614   a.  As also illustrated in  FIG. 17B , the battery  1004  may be coupled to a region of the interface support portion  1603  location between the processing unit  1704  and the sensor array  600 .  
      Referring back to  FIG. 17A , and in accordance with principles of several embodiments of the present invention, the cartridge retainment unit  136  is substantially prevented from experiencing traverse, longitudinal, or axial movement once received and secured within the port  1604 . In one embodiment, a plurality of cartridge retainment unit port guides  1720  are coupled to internal surfaces of the port  1604  and are dimensioned such that, when coupled to the internal surfaces of a port  1604 , conform to exterior dimensions of the cartridge retainment unit  136  to substantially prevent transverse or longitudinal movement of the cartridge retainment unit  136  within port  1604 . By substantially preventing transverse, longitudinal, and axial movement of the cartridge retainment unit  136  within the port  1604 , cartridges  1502  can be reliably and consistently ejected and activated by the actuator unit  134 . In another embodiment, the cartridge retainment unit port guides  1720  are formed of a polymeric material such as an acetal to reduce friction and wear between the frame  1601  and the cartridge retainment unit  136 .  
      According to principles of several embodiments of the present invention, cartridges  1502  can be substantially prevented from accidentally falling out of the within a cartridge retainment unit  136 . In one embodiment, the cartridge containment unit  1730  is coupled to a region of the frame  1601  constituting an external surface of the lower bracket portion  1606  and can substantially prevent a cartridge  1502  from accidentally falling out of the pod  1600 . The solenoid  1731  may be provided as a pull type solenoid, magnetically coupled to plunger  1732 . Spring  1733  is coupled between the solenoid  1731  and a terminal end of the plunger  1732 . A first terminal end  1735   a  of the connection rod  1734  is coupled (e.g., rotatably) to a terminal end of the plunger  1732  while a second terminal end  1735   b  of the connection rod  1734  is coupled (e.g., rotatably) to horn  1736 . The horn  1736  is fixedly connected to a first (e.g., external) surface of the gate  1737  and the gate  1737  is connected (e.g., hingedly) to the region of the frame  1601  constituting the external surface of the lower bracket portion  1606 . A pad  1738  is coupled to a second (e.g., internal) surface of the gate  1737  and protrudes from the internal surface of the gate  1737  such that the pad  1738  is proximate to, or contacts, a portion of a cartridge  1502  that has been indexed for ejection.  
      When the solenoid  1731  is deactivated, spring  1733  naturally biases the plunger  1732 , and thus the connection rod  1734  in an extended position, resulting in the gate  1737  at least partially closing the discharge opening  1709 . When the solenoid  1731  is activated, the spring  1733  is compressed and the plunger  1732  is magnetically and linearly biased into a retracted position. The rotatable connection between the connection rod  1734  and the horn  1736  translates the linear retracting motion into a rotating motion of the gate  1737 , resulting in the gate  1737  rotating to open the discharge opening  1709  about its hinged connection to the region of the frame  1601  constituting the external surface of the lower bracket portion  1606 . Accordingly, the gate  1737  acts as a trap door to at least partially overlap the discharge opening  1709  and the ejection opening  1918 . As a result, cartridges are prevented from inadvertently falling out of the pod  1600  when no ejection event has occurred. In one embodiment, the solenoid  1731  is activated either immediately before or substantially when the solenoid  1508  of a corresponding cylinder assembly  1507  is activated to eject a cartridge  1502 . In one embodiment, a cover (e.g., formed of a polymeric material) (not shown) is attached to the frame  1601  to cover each cartridge containment units  1730 .  
       FIG. 18  illustrates a second interior perspective view of the pod shown in  FIG. 16 .  
      Referring to  FIG. 18 , a retainment pin guide  1802  can be provided with the aforementioned second retainment pin opening  1804  defined therein. In the illustrated embodiment, a catch  1806  is attached to a portion of the frame  1601  constituting terminal frontwall portion  1808  of port  1604 .  
      In one embodiment, the retainment pin guide  1802  is attached to region of the interior sidewall surface  1704  within the port  1604  such that the second retainment pin opening  1804  becomes substantially aligned with the first retainment pin opening  1607  when the cartridge retainment unit  136  is properly inserted into port  1604 . A retainment pin  1608  can be inserted into the aligned first and second retainment pin openings  1607  and  1804 , respectively, thereby substantially preventing axial movement of the cartridge retainment unit  136  along the length of port  1604 .  
      In one embodiment, the catch  1806  is adapted to mate with strike included within the cartridge retainment unit  136  (see, for example,  1915  in  FIG. 19 ). The catch  1806  may, for example, be provided as a three-way spring ball tension catch having, for example, an 8.5 lb release load (e.g., applied by a user pulling on handle  1914  to remove the cartridge retainment unit  136  from its respective port). Once the catch  1806  is mated to a respective strike, axial movement of the cartridge retainment unit  136  along the length of port  1604  is substantially prevented.  
       FIG. 19  illustrates a perspective view of a cartridge retainment unit according to one embodiment of the present invention.  
      Referring to  FIG. 19 , a cartridge retainment unit  136  according to principles of several embodiments of the present invention includes a magazine assembly  1910  and a cartridge moving unit  1920 . The magazine assembly  1910  includes a magazine housing  1911 , an alignment block  1912 , a magazine end cap  1913 , and, optionally, a handle  1914 . The alignment block  1912  includes the aforementioned strike  1915  and a catch mechanism  1917 . A first opening  1916  (e.g., a rod opening) is formed through a first portion of the magazine housing  1911  and a second opening  1918  (e.g., an ejection opening) is formed through a second portion of the magazine housing  1911 , opposite to the first opening  1916 . The cartridge moving unit  1920  includes a ram  1922 , a plastic glide  1924 , and a sensor target  1926 .  
      In one embodiment, the alignment block  1912  is coupled to a first end portion of the magazine housing  1911 , the magazine end cap  1913  is coupled to a second end portion of the magazine housing  1911 , and, optionally, the handle  1914  is coupled to an external surface of the magazine end cap  1913 . Accordingly, the magazine housing  1911 , alignment block  1912 , and magazine end cap  1913  provide a magazine assembly  1910  defining at least a semi-closed interior space within which the cartridge moving unit  1920  and cartridges  1502  are disposed.  
      In one embodiment, the magazine housing  1911  defines the exterior dimensions to which the interior dimensions of the port  1604  substantially conform. In another embodiment, a first opposing pair of first interior surfaces of the magazine housing  1911  (e.g., top and bottom oriented interior surfaces of the magazine housing  1911  as shown in  FIG. 19 ) and a second opposing pair of interior surfaces of the magazine housing  1911  (e.g., left and right oriented interior surfaces of the magazine housing  1911  as shown in  FIG. 19 ) conform substantially to the length and width (e.g., diameter), respectively, of the cartridges  1502  disposed therein to minimize movement of the cartridges  1502  in all directions except along the length of the magazine housing  1911 .  
      In one embodiment, the first opening  1916  is formed through one of the first pair of opposing interior surfaces and is adapted to receive the tip  1518  of striking rod  1516 . In one embodiment, the second opening  1918  is formed through the other of the first pair of opposing interior surfaces and is configured so as to allow a cartridge  1502  to be ejected from the magazine  1910  when the tip  1518  contacts the cartridge  1502 . In yet another embodiment, the catch mechanism  1917  is arranged between the first and second openings  1916  and  1918 , respectively.  
      According to principles of various embodiments, the cartridge moving unit  1920  applies a substantially constant force to the cartridges  1502  regardless of the number of cartridges  1502  contained within the magazine assembly  1910 . In one embodiment, the cartridge moving unit  1920  includes a ram  1922  coupled to a rear interior surface of the magazine housing  1911  via the aforementioned constant force spring  1610  (see, for example,  FIG. 16 ). Accordingly, the cartridge moving unit  1920  pushes against the remaining cartridges  1502  when a cartridge  1502  is ejected. As a result, a consecutively disposed cartridge  1502  is indexed for a subsequent ejection event. In one embodiment, the cartridge moving unit  1920  further includes a means for reducing a force hindering motion of the ram  1922  between the first and/or second pair of opposing interior surfaces (e.g., a plastic glide  1926  around edge portions of the ram  1922 . In a further embodiment, the cartridge moving unit  1920  further includes a sensor target  1926  (e.g., a magnet) for the aforementioned sensor circuitry  518  to detect and generate signals based on results of the detection.  
      In one embodiment, the catch mechanism  1917  is adapted to partially overlap a portion of the cartridge  1502  between the first and second openings  1916  and  1918  and protrude from the contact surfaces  2002   a  and  2004   a.  Configured as described above, the catch mechanism  1917  retains the cartridge  1502  within the magazine housing  1911  until the force generated by the tip  1518  of striking rod  1516  exceeds both the force applied by the ram  1922  and a frictional force between the catch mechanism  1917  and the cartridge  1502 . In another embodiment, the catch mechanism  1917  is configured so as to deflect the cartridge  1502  away from the standoff elements  2002  and  2004  as it is being ejected to reduce friction between the standoff elements  2002  and  2004  and the cartridge  1502 .  
       FIG. 20  illustrates a bottom view of the cartridge retainment unit shown in  FIG. 19 .  
      As shown in  FIG. 20 , the alignment block  1912  includes first and second standoff elements  2002  and  2004 , each having a contact surface  2002   a  and  2004   a,  respectively, in addition to the catch mechanism  1917 . In one embodiment, the catch mechanism  1917  includes an ejection roller  2006 .  
      In one embodiment, the standoff elements  2002  and  2004  substantially control the orientation of the cartridge  1502  between the first and second openings  1916  and  1918  to a desired orientation within the magazine assembly  1910  such that the cartridges  1502  can be reliably and consistently ejected and activated by the actuator unit  134 . Accordingly, the contact surfaces  2002   a  and  2004   a  of the first and second standoff elements  2002  and  2004 , respectively, both contact the exterior surface of a cartridge  1502  indexed between the first and second openings  1916  and  1918  and have dimensions conforming to those of the cartridge  1502 . In one embodiment, the first and second standoff elements  2002  and  2004  are spaced apart from each other by a predetermined distance, are substantially parallel to each other, and are substantially parallel to a longitudinal axis of the cartridge  1502 .  
      As illustrated, the catch mechanism  1917  includes an ejection roller  2006  that is adapted to facilitate movement of the cartridge  1502  as it is being ejected from the magazine housing  1911 . In one embodiment is the ejection roller  2006  is provided as a bearing, a bushing, or the like, and may be rotatably coupled between the standoff elements  2004  and  2006 .  
      As discussed above, the cartridge retainment unit  136  facilitates the ejection of cartridges  1502  and is magnetically coupled to sensor circuitry  518  mounted within port  1604 . In accordance with several alternate embodiments, however, the cartridge retainment unit  136  may be replaced with a similarly dimensioned component (e.g., an auxiliary subsystem  180 ) containing any desired active and/or passive system and the sensor circuitry  518  may be configured to electrically communicate with the auxiliary subsystem  180 . Accordingly, it is possible to add functionality to the cartridge ejection and data acquisition system  100  as desired.  
      According to several embodiments of the present invention, the cartridge retainment unit  136  can retain a cartridge  1502  adapted to perform substantially any process or combination of processes. Moreover, the cartridge retainment unit  136  can retain a plurality of cartridges  1502  adapted to perform identical or different processes. For purposes of discussion, the term “process” encompasses both active and passive processes employed in electrical systems, chemical systems, nuclear systems, biological systems, and the like, or combinations thereof. Exemplary processes include, for example, sensory processes, data storage processes, communications processes, descent-assistance processes, discharge processes, timing processes, and the like, and combinations thereof. Accordingly, and within cartridges  1502  adapted to perform a combination of processes, systems adapted to perform each process can be coupled together directly (e.g., via a suitable electrical, chemical, mechanical connection, etc.) or via a controller adapted to synchronize initiation of the various processes. The aforementioned processes can be initiated either dependently or independently of the ejection event itself. In one embodiment, the sensory, data storage, communications, descent-assistance, and discharge processes can be initiated by an electronic signal. In another embodiment, initiation of sensory, data storage, communications, descent-assistance, and discharge processes can be delayed in accordance with a timing process. In such an embodiment, initiation of the timing process is dependent upon the ejection event itself while initiation of the sensory, data storage, communications, descent-assistance, and/or discharge processes is dependent upon the timing process. Systems within cartridges adapted to perform timing processes include a timing device such as a clock, a fuse, or the like, or combinations thereof.  
      Systems within cartridges adapted to perform sensory processes include, for example, weather/environmental sensors, electromagnetic sensors, acoustic/vibration sensors, navigational sensors, and the like.  
      In one embodiment, weather/environmental sensors generate data characterizing weather/meteorological conditions (e.g., humidity, barometric pressure, wind speed, air temperature, rain levels, etc.) in the environment surrounding an ejected cartridge, the presence of certain gases (e.g., propane, cyanide, ozone, etc.), biological materials, chemical materials, nuclear materials, etc., present in the environment surrounding an ejected cartridge (e.g., as the ejected cartridge descends and/or after the ejected cartridge has reached its target area), and the like.  
      In one embodiment, electromagnetic sensors generate data characterizing substantially any wavelength. (or range of wavelengths) of electromagnetic radiation (e.g., radiowave, microwave, infra-red, ultra-violet, X-ray, visible, low-light, etc.) sensed in the environment surrounding an ejected cartridge (e.g., as the ejected cartridge descends and/or after the ejected cartridge has reached its target area). Such electromagnetic sensors may, for example, be provided as radio or microwave antennae, a camera (e.g., video, still-picture, or a combination thereof), and the like. In one embodiment, a camera can be provided as a pan/tilt camera system mounted within, on a side of the cartridge, or on the nose (i.e., downwardly facing portion) of the cartridge. Such a camera system can be coupled to a system adapted to perform a communications process and can, therefore, be remotely controlled by a user.  
      In one embodiment, acoustic/vibration sensors generate data characterizing sound or other vibrations sensed in the environment surrounding an ejected cartridge (e.g., as the ejected cartridge descends and/or after the ejected cartridge has reached its target area). In one embodiment, the acoustic sensors provided can generate data characterizing sound having frequencies audible to humans (i.e., sounds having a frequency between 20 hertz and 20,000 hertz), infrasound (i.e., sounds having a frequency between 10 hertz to 0.001 hertz), and ultrasound (i.e., sounds having a frequency above 20,000 hertz).  
      In one embodiment, navigational sensors generate data characterizing, the latitude, longitude, altitude, etc., of an ejected cartridge (e.g., as the ejected cartridge descends and/or after the ejected cartridge has reached its target area). In one embodiment, the navigational sensors may be provided as devices such as global positioning systems (GPS) and the like.  
      Systems within cartridges adapted to perform data storage processes include, for example, any suitable electronic and/or chemical data storage system.  
      Systems within cartridges adapted to perform communications processes include communications devices such as radio or microwave transmitters that transmit data generated by the aforementioned systems adapted to perform sensory processes (e.g., either in real-time or after it has been stored as a result of a data storage process), radio or microwave receivers that receive instructions to initiate processes, transceivers, beacons, and the like. In one embodiment, the transmitters transmit data to a receiver located, for example, within the pod  1600 , somewhere on the structure to which the pod  1600  is mounted, or at some location remote to the pod  1600  and the structure to which the pod  1600  is mounted (e.g., within a remotely located vehicle, within a hand-held device, etc.). In another embodiment, beacons are provided as radio beacons, strobed or continuous infra-red or visible light emitting lamps (e.g., halogen, LED, etc.), chemical flares, sound-emitting beacons (e.g., for use in navigation applications, etc.) and the like.  
      Systems within cartridges adapted to perform descent- assistance processes include, for example, deployable parachutes or other descent-assistance devices that can slow the speed of an ejected cartridge as it descends through the air. In one embodiment, the descent-assistance device may be provided as a servo of a piezoelectric driven fin, nose, etc. that can help to steer the cartridge  1502  toward a target as it descends through its environment (e.g., air or water).  
      Systems within cartridges adapted to perform discharge processes can discharge, for example, pesticide (e.g., to kill unwanted pests such as rodents, insects, etc.), tear gas, radar countermeasures (e.g., chaff), dye (e.g., phosphorescent, colored, etc), smoke, heat (e.g., via chemical flare), and the like. In one embodiment, the cartridge may, for example, be provided as a bomb, a mine, a flash grenade, or other similar device containing an explosive material. An exemplary cartridge, containing a system adapted to discharge a plume of smoke concurrently with an ejection event, will now be discussed in greater detail with respect to FIGS.  21  to  24 .  
      As shown in  FIG. 21 , a cartridge  1502  includes a system implemented to discharge a plume of smoke. Such a cartridge  1502  can include a first (e.g., exterior) tube  2102 , a first (e.g., activation) end cap  2110  coupled to a first end of the exterior tube  2102 , and second (e.g., cartridge base) end cap  2120  coupled to a second end of the exterior tube  2102 , wherein the exterior tube  2102  is contains a smoke generating material (not shown). The cartridge  1502  may, for example, be about  6 . 47  inches in length. The activation end cap  2110  includes a nozzle  2112  formed of complementary first and second nozzle sections  2112   a  and  2112   b.  An aperture  2114  is defined within the nozzle  2112  through which smoke exits the cartridge  1502 .  
      In one embodiment, the exterior tube  2102  is formed of a material such as spiral wrapped paper. The exterior tube  2102  may, for example, be about 5.94 inches in length and have an outer diameter of about 1.97 inches and an inner diameter of about 1.65 inches.  
      Referring to  FIG. 22 , the cartridge  1502  further comprises a process capsule  2230  (e.g., a smoke generating capsule) disposed within the exterior tube  2102 . In the illustrated embodiment, the smoke capsule  2230  includes a second (e.g., interior) tube  2232  containing a smoke generating material  2234  capable of generating smoke upon being ignited and sealed at one end thereof with a capsule base cap  2236 . As illustrated, the activation end cap  2110  further includes the aforementioned pressure-sensitive activation unit  2211  (e.g., pressure-sensitive detonation unit such as a shotgun primer) fixed within the nozzle  2112 . In the illustrated embodiment, each nozzle section of nozzle  2112  includes a main body  2213 , a lip  2215  protruding away from the main body  2213  and configured to overlap the first end of the exterior tube  2102 , a debris trap  2217  defined within the main body  2213 , and an activation unit stage  2219  defined within the main body  2213 . As illustrated, the cartridge base end cap  2120  includes main body  2221  and a lip  2223  protruding from the main body  2221 , a cavity  2225  formed within the main body  2221 , and a ballast material  2227  (e.g., a clay puck) disposed within the cavity  2225 . In one embodiment, the ballast material  2227  ensures that the activation end cap  2110  is oriented in an upward direction when the cartridge  1502  is ejected over a target area that may include water (e.g., in a cranberry field). Also illustrated is a thermally insulative material  2240  (e.g., air) arranged between the interior surface of the exterior tube  2102  and the exterior surface of the interior tube  2232 .  
      In one embodiment, the interior tube  2232  may, for example, be about  4  inches in length and have an outer diameter of about  1 . 63  inches and an inner diameter of about 1.25 inches.  
      In one embodiment, the capsule base cap  2236  is sealed to an end of the interior tube  2232  via a friction fit. In another embodiment, the capsule base cap  2236  is provided as a paper cap.  
      In one embodiment, the smoke generating material  2234  comprises a mixture of about 50% sugar (e.g., sucrose) and about 50% KNO 3 . In other embodiments, the smoke generating material  2234  may comprise a mixture of about 48% KNO 3 , about 46% sulfur (S), about 3% sucrose, and about 3% charcoal or a mixture of about 50% pigment, about 30% potassium chlorate (KClO 3 ), and about 20% sugar (e.g., lactose). In one embodiment of the present invention, the smoke capsule  2230  contains enough smoke generating material  2234  to generate between about 1½ to about 2½ minutes worth of smoke. For example, the smoke capsule  2230  may contain about 80 grams of smoke generating material  2234 . It will be appreciated that the amount of smoke generating material  2234  within the smoke capsule  2230  may be varied as desired. Although not explicitly shown, a first end of the interior tube  2232  may be sealed using a rupturable sealing material (or structure) capable of being ruptured upon activation of the pressure-sensitive activation unit  2211 .  
      In one embodiment, each nozzle section  2112   a  and  2112   b,  respectively, includes a main body  2213  configured to be inserted into and extend beyond the exterior tube  2102  and to abut against a first end of the smoke capsule  2230 . Further, each nozzle section  2112   a  and  2112   b  is formed from a polymeric material sufficiently resistant to thermal deformation from heat generated upon detonating the pressure-sensitive activation unit  2211 , upon igniting the ignition-assisting film, and upon igniting the smoke generating material  2234  while also being resistant to mechanical deformation due from the physical impacts during ejection from the pod  1600  and upon collision with the target area (e.g., an agricultural field). Accordingly, the nozzle sections  2112   a  and  2112   b,  in addition to the cartridge base end cap  2120 , can be formed from a thermoset or a thermoplastic (e.g., Nylon 66) via any suitable process such as injection molding or the like.  
      In one embodiment, the debris trap  2217  is provided as a channel formed in the main body  2213  that extends tortuously through the thickness of thereof such that the debris trap  2217  is in fluid communication with the smoke generating capsule and with the environment external to the nozzle section. In one embodiment, the debris trap  2217  is hollow. In another embodiment, the debris trap  2217  is not filled with a choke material. By providing the debris trap  2217  as a tortuous channel, exhaust material (i.e., hot particulate material, heavier than the smoke generate) is prevented from exiting the cartridge  1502 , thereby helping to minimize the risk that the activated cartridge  1502  is a fire hazard within the target area.  
      In one embodiment, the activation unit stage  2219  of each nozzle section includes a recess pattern formed within the main body  2213  that is substantially conformal to exterior dimensions of the pressure-sensitive activation unit  2211  and receives the edge of the pressure-sensitive activation unit  2211 .  
      Thus, to form the activation end cap  2110 , a first portion of the pressure-sensitive activation unit  2211  is inserted into the activation unit stage  2219  of one of the first and second nozzle sections  2112   a  and  2112   b.  The activation unit stage  2219  of the other of the first and second nozzle sections  2112   a  and  2112   b  is subsequently introduced to receive a second portion of the pressure-sensitive activation unit  2211 , thereby coupling the first nozzle section  2112   a  with the second nozzle section  2112   b  and forming the nozzle  2112 . Moreover, upon coupling the first and second nozzle sections  2112   a  and  2112   b,  portions of each debris trap  2217  arranged above the activation unit stage are substantially aligned to form a tapered aperture  2114  that is coaxially aligned with, and completely exposes the pressure-sensitive activation unit  2211  to the tip  1518  of the striking rod  1516 .  
      In one embodiment, the main body  2221  is configured to be inserted into and extend beyond the exterior tube  2102  and to abut against a second end of the smoke capsule  2230 . In another embodiment, the lip  2223  is configured to overlap the second end of the exterior tube  2102  and, optionally, be overlapped by the aforementioned ejection guide  2004 .  
       FIGS. 23 and 24  illustrate an ignition assistor in accordance with various embodiments of the present invention.  
      Referring generally to  FIGS. 23 and 24 , an ignition-assistor may be provided between the activation end cap  2211  and the smoke generating material  2234  to increase the efficiency with which smoke is generated by the smoke generating capsule  2230 .  
      Referring to the embodiment exemplarily illustrated in  FIG. 23 , the ignition-assistor includes an ignition-assisting material  2302  sandwiched between two rupturable films  2304 . In one embodiment, the rupturable films  2304  are formed from a material such as MYLAR, saran, etc., and have thickness enabling them to rupture when pressure-sensitive activation unit  2211  is ignited. In one embodiment, the ignition-assisting material  2302  has a higher volatility than smoke generating material  2234  contained within the smoke capsule  2230 . For example, the ignition-assisting material  2302  may be provided as about 3 grams of a mixture of about 50% black powder and about 50% potassium nitrate (KNO 3 ).  
      Referring to another embodiment exemplarily illustrated in  FIG. 24 , the ignition assistor includes an ignitable compound  2402  disposed on, for example, the smoke generating material  2234 . In one embodiment, the ignitable compound has a higher volatility than the smoke generating material  2234 . For example, the ignitable compound can be formed by mixing black powder mixed with a solvent such as lacquer thinner to form a paste. The lacquer thinner evaporates, leaving a solid form of black powder. In another embodiment the ignitable compound includes a dry chemical mixture that is pressed firmly into the interior tube  2232  and compacted to the point that it holds its within the interior tube  2232 .  
      Having described the structure of an exemplary cartridge  1502  in accordance with various embodiments of the present invention illustrated in FIGS.  21  to  24 , an exemplary method of assembling the aforementioned cartridge components will now be provided. Initially, the nozzle  2112  is inserted into the exterior tube  2102 . Upon inserting the nozzle  2112 , the pressure-sensitive activation unit  2211  is positionally fixed within the recess patterns of the combined activation unit stages  2219 , thereby allowing the tip  1518  of the striking rod  1516  to reliably and consistently contact the pressure-sensitive activation unit  2211  with sufficient force to eject the cartridge  1502  from the cartridge retainment unit  136  and to activate (e.g., detonate) the pressure-sensitive activation unit  2211 . The smoke capsule  2230  is inserted into the exterior tube  2102  in such a manner as to abut against the activation end cap  2110 . Any of the aforementioned ignition assistors exemplarily discussed with respect to  FIGS. 23 and 24  are provided between the activation end cap  2110  and the smoke generating material  2234 . Subsequently, the cartridge base end cap  2120  is coupled to the second end of the exterior tube  2102  (e.g., with the ballast material  2227  arranged within cavity  2225 ). According to principles of several embodiments, the activation and cartridge base end caps  2110  and  2120 , respectively, can be coupled to the exterior tube  2102  via any known means (e.g., glue, pins driven through the exterior tube  2102  and into the main bodies  2113  and  2221 , etc.).  
      Upon detonating the pressure-sensitive activation unit  2211  of the cartridge  1502  constructed as discussed above, the aforementioned ignition assistor ignites and serves as a means for igniting the smoke generating material  2234  within the smoke capsule  2230  and causing the smoke generating material  2234  to generate smoke, wherein the generated flows through the combined debris traps  2215  through the aperture  2114  and emerges outside the cartridge  1502  as a plume of smoke. In one embodiment, the combined effects of the activation end cap  2110  and the thermally insulative material  2240  enables the cartridge  1502  shown in  FIGS. 21 and 22  to not burn skin or other materials that come into contact with exterior surfaces thereof, even when the skin or other material is directly over the aperture  2114  or in direct contact with the exterior surface of the exterior tube  2102 .  
      In light of the various embodiments described above, it will be appreciated that the system  100  may be adapted for use in a multitude of applications other than determining localized meteorological conditions to facilitate aerial agricultural pesticide spraying. For example, the cartridge  1502  discussed above can be used in determining localized meteorological conditions to facilitate aerial pesticide spraying in “Rights of Way” such as railroads, gas transmission pipelines, high voltage transmission lines, etc. Moreover, the cartridge  1502  discussed above can be used to mark agricultural fields having mature crops ready for harvest, to mark agricultural fields in need of pesticide spraying, etc.  
      Apart from agricultural use, it is appreciated that the embodiments described may be readily extended to applications involving cartridge placement in a target area that is either hazardous or difficult to reach, monitoring processes, detection, tracking processes, rescue operations, crowd/riot control, forest/brushland maintenance, and the like.  
      For example, cartridges can be used as a marker. The marking cartridge can include an infra-red or visible light emitting beacon, flare, dye, smoke, etc. Such a marker cartridge can, for example, be ejected from the cartridge retainment unit  136  to facilitate helicopter extraction landing zone. Similar cartridges may also be used in rescue applications to identify the location of a person in need of rescue, or mark the location of a leak (e.g., oil, chemical, water, etc.). Similar cartridges may also be used by a port control authority/harbor commission working with port captains and pilots to help guide ships in inclement weather while bringing ships to berth. Cartridges containing a dye and that break upon impact with the ground may be used to mark areas of interest (e.g., the U.S. Coast Guard or U.S. Army Corp of Engineers can mark weak areas in a levee system, or the Department of Forestry can mark trees and brush to be removed.)  
      Cartridges provided with, for example, chemical flares can be ejected over target areas where controlled burning of brush is required.  
      Suitably equipped cartridges may be used to outline the border of an oil spill, or contaminated area. Such cartridge systems may include, for example, a GPS or other navigational system and radio transmitter that relays its position to a receiver. In use, several of these cartridges can be ejected along the edge of the contaminated area to produce a real time plot of the growth of the contamination.  
      Suitably equipped cartridges may be used in security applications by ejecting cartridges from the cartridge retainment unit  136  around an area that needs to be secure. Such cartridges may include, for example, acoustic/vibration and/or motion sensors and/or a video camera and a radio transmitter. Fitted as described above, the cartridge notifies the receiver if an intruder is breaching the security line.  
      Cartridges equipped, for example, with a descent-assistance device (e.g. parachute) and a tear gas discharge system may be employed in crowd-control applications.  
      Cartridges equipped with any combination of suitable weather/environmental sensors, navigational sensors, a radio transmitter, and, optionally, a descent-assistance device (e.g. parachute) can be used to monitor storm conditions within the atmosphere as the cartridge descends.  
      Cartridges equipped with any combination of suitable video camera and/or still-picture camera can photograph or video objects above or below it during descent and/or while on the ground.  
      Cartridges can be equipped to generate data characterizing the presence of standing water. After being dropped in a dry area, the cartridge will remain dormant until the presences of water is detected. The cartridge then becomes active and transmits its location to a receiver. Such data can then be used by city governments to monitor possible flood locations and also set priorities for implementing mosquito control programs.  
      A cartridge can be adapted for being ejected into the water and contain sensors, such as, sonar for underwater mapping. Sonar cartridges could also be used as a listening device to detect sea life, seismic activity (e.g. underwater volcanoes), and man-made vessels.  
      Cartridges equipped with any combination of chemical, biological, and/or radiological sensors and a transmitter can be used as detection devices. When ejected from the cartridge retainment unit  136  over a target area (e.g., a hazardous area), such a cartridge detects the presence of a known substance and relays, to the receiver, the detectable levels of substance present in the target area. Use of such cartridges would be benefited by Homeland Security, military, and EPA applications. Such cartridges may also be equipped with a descent-assistance device (e.g. a parachute), enabling the cartridge to detect levels of a substance through different altitudes in the atmosphere.  
      In light of the various embodiments described above, it will be appreciated that the pod  1600  may be mounted to structures or vehicles other than aerial applicators. For example, the pod  1600  may be mounted to commercial aircraft (e.g., passenger airplanes, cargo airplanes, etc.), reconnaissance blimps, unmanned aerial vehicles, watercraft (e.g., boats, buoys, submersible watercraft, etc.), platforms located within a target area, and the like.  
      Although it has been described above that one cartridge is ejected in response to an eject command transmitted from the controller subsystem  110  to the actuator unit  134 , it will be appreciated that a series of cartridges (equipped, for example, with a smoke discharge system) may be ejected automatically in one of two modes. For example, in a “rapid fire” mode, a predetermined number, or all cartridges within the cartridge retainment unit  136  are immediately ejected upon being indexed. In a “slow fire” mode wherein a predetermined number or all cartridges within the cartridge retainment unit  136  are ejected after having been indexed for a predetermined amount of time) in response to an eject command transmitted from the controller subsystem  110  to the actuator unit  134 .  
      In one embodiment, a plurality of pods  1600  are used by one or more users in one or more locations (e.g., zip codes, cities, counties, states, countries, geographic regions, climatic regions, etc.), and data generated by the cartridges ejected therefrom is transmitted to a host system where the data is compiled, categorized according to the type of information the data characterizes, and made available as a composite information source. Accordingly, the composite information source enables comprehensive monitoring of environmental patterns (both natural and man-made) such as global warming, pollution, urban growth, storm damage, pesticide use, weather patterns, and the like, in locations where the system  100  described above is used. In one embodiment, the composite information source is provided as a time-lapse composite image of the categorized data overlaid onto map specific to a location selected by a user of the composite information source.  
      While the invention herein disclosed has been described by means of specific embodiments, examples and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.