Abstract:
The missile system disclosed herein involves directing a beam from a  modeely powered laser on a taget for such time that a hot spot is produced. This hot spot is then used as a target for a cooperating infrared seeking missile.

Description:
BACKGROUND OF THE INVENTION 
     Previous missile systems for use against tanks and trucks required continuous guidance of the missile to the target or a heat seeking missile which homed in on the heat of the engine of the target vehicle. 
     It is an object of this invention to provide a missile system which does not require continuous operator guidance of the missile to the target, or continuous laser illumination. 
     A further object of the invention is to provide a missile system which employs a heat seeking missile which is effective against parked targets. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The single FIGURE of the drawing is an artist&#39;s conception illustrating the missile system of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawing, the missile system of the present invention uses a laser 10 for thermally marking a target 12 creating a hot spot on the target. A heat seeking missile 14 launched from a launcher 16 then homes in on the hot spot thus created. The launcher may be located adjacent the laser or remote therefrom as illustrated. 
     The following table represents five different seekers contemplated for use in heat seeking missiles for the missile system described herein. 
     
                                           TABLE I__________________________________________________________________________           Target Emission Power           (normal to sensor)    Threshold      Band (watts)     Background at 30° C.Sensor    (watts/cm.sup.2)      (microns)           1 km               2 km                   3 km                       (watts/cm.sup.2)__________________________________________________________________________1   6 × 10.sup.-11      3-5  1.885               7.55                   17.0                       7.5 × 10.sup.-42   2 × 10.sup.-12      3-5   0.0628                0.251                    0.565                       7.5 × 10.sup.-43   2 × 10.sup.-11       8-14           0.628               2.51                   5.65                       0.2124   3 × 10.sup.-11      2.72-3.30           0.942               3.77                   8.50                       0.17 × 10.sup.-45   4.5 × 10.sup.-11      2.8-3.6           1.42               5.67                   12.75                       0.45 × 10.sup.-4__________________________________________________________________________ 
    
     The laser power required for use with the several seekers depends further on the legnth of time the laser is turned on, the size of the spot illuminated, the time delay of acquisition and launch of the missile and the range to the target. The following charts show the laser power required for the several variables stated. 
     
                       TABLE II______________________________________SENSOR #1Spot  Beam                         Closure SpeedSize  Time    Delay   Laser Power (kW)                              V.sub.c at R.sub.o =r.sub.o τ   τ.sub.d                 at Range R.sub.o                              1 km(cm)  (sec)   (sec)   1 km 2 km  3 km  (m/sec)______________________________________5     1       1        63  100   126   375         5       120  200   250   125 3       1        26   42    57   125         5        43   72    93   100 10      1        11   18    23    9025    1       1       365  780   1130  250         5       740  1440  1950   65 3       1       143  325   415   125         5       230  470   650    60 10      1        70  130          6050    3       1       260  690   1150  125         5       450  1150  1850   50______________________________________ 
    
     
                       TABLE III______________________________________SENSOR # 2Spot  Beam                         Closure SpeedSize  Time    Delay   Laser Power (kW)                              V.sub.c at R.sub.o =r.sub.o τ   τ.sub.d                 at Range R.sub.o                              1 km(cm)  (sec)   (sec)   1 km 2 km  3 km  (m/sec)______________________________________5     1       1       14.2 28    40    250         5       27   54    70    85 3       1       6.3  12    17    125         5       7.8  21    28    90 10      1       2.8    5.0   7.3 7025    1       1       24   78    165   125         5       36   144   310   40 3       1       11   33    73    60         5       13   46    100   50 10      1       3.9    14.5                            30    4050    3       1            47    75    100         5            66    130   45______________________________________ 
    
     
                       TABLE IV______________________________________SENSOR # 3Spot  Beam                         Closure SpeedSize  Time    Delay   Laser Power (kW)                              V.sub.c at R.sub.o =r.sub.o τ   τ.sub.d                 at Range R.sub.o                              1 km(cm)  (sec)   (sec)   1 km  2 km 3 km  (m/sec)______________________________________5     1       1       15    44   82    40         5       29    85   160   80 3       1         6.3 20   36    18         5       11    32   58    6025    1       1       20    67   157   80         5       32    140  280   140 3       1        9    29   65    35         5       13    54   100   50______________________________________ 
    
     
                       TABLE V______________________________________SENSORS # 4 AND 5Spot  Beam                         Closure SpeedSize  Time    Delay   Laser Power (kW)                              V.sub.c at R.sub.o =r.sub.o τ   τ.sub.d                 at Range R.sub.o                              1 km(cm)  (sec)   (sec)   1 km 2 km  3 km  (m/sec)______________________________________Sensor 45     3       1       36   50    66    300         5       65   87    115   150Sensor 55     3       1       37   52    65    300         5       65   90    115   150______________________________________ 
    
     The above tables give figures representative of thick steel targets for various ranges up to 3 km and various times of exposure and spot sizes. 
     The following table gives similar figures for use of the system against relatively thin aluminum targets. 
     
                       TABLE VI______________________________________Spot Size:    r.sub.o =                5 cmThickness:    c =    0.3 cmBeam Time:    τ =                3 secDelay:        τ.sub.d =                5 secConvection:   h =    0.002 cal/cm.sup.2 sec °K.______________________________________  Laser Power (kW)  - a = ε = 0.2               - a = 0.5   ε = 0.7  Range        RangeSensor   1 km   2 km     3 km 1 km   2 km 3 km______________________________________1        43     70       95   11.6   18   242        11     20       29   1.9    4.7  73        14     40       70   2      6    114        61     88       115  17.4   25.2 31.25        60     89       106  12.2   16.4 21.2  Plate Thickness: c = 0.2 cm4        42     60       75   17.4   25.2 31.45        41     61       77   6.5    19.0 21.2______________________________________ 
    
     In general it can be seen from the above charts that a medium powered laser 50 kw to 150 kw with an average laser application time of approximately three seconds will create a hot spot suitale for use with most all of the different types of seekers at ranges up to 3 km.