referring now to the drawings , there is shown in fig1 a projectile 20 comprising a fin - stabilized he round fully telescoped within a cartridge case 22 . the interior of the case 22 includes a propellant chamber 23 in communication with a powder - charge cup 24 . an electric primer 25 includes an electrical terminal 30 located in a primer cup 26 at the rear exterior of the case 22 . the primer further includes an electrically insulated feed through that passes through the case 22 and extends into electrical contact with a digital time fuze 28 located in a booster cavity 29 at the rear of the projectile 20 . the cavity 29 also houses a booster charge 32 and a safing and arming ( s & amp ; a ) mechanism 31 with a squib 27 to fire the booster charge 32 . the purpose of the booster charge 32 is to impart a momentary acceleration to the round while not detonating the main charge 48 . a fin assembly 35 , mounted at the rear of the projectile 20 , has a number of retracted fins 36 that are mounted on pivots 33 . after the projectile 20 is fired and it leaves the gun tube , the retracted fins 36 will rotate on the pivots 33 to extend radially into a position that provides aerodynamic stability to the projectile 20 . a base - mounted , time fuze in combination with a fully telescoped round of the type disclosed herein is also described in detail in my copending and commonly assigned u . s . patent application , ser . no . 07 / 676 , 610 , filed on mar . 28 , 1991 , entitled electric fuze with selectable modes , which application is incorporated herein by reference . a cavity 47 , located in the main body of the projectile 20 , holds the main he charge 48 . directly in front of the chamber 47 is a cone - shaped nose 37 that houses a proximity / contact fuze 34 . the forward section 38 houses a high negative - g contact switch 39 , a positive - g enable switch 40 and an antenna 41 . switch 39 is designed to close in response to negative reaction forces created when the projectile 20 makes impact with a hard target such as the earth , a bridge , a tank , or like object . the positive - g enable switch 40 is designed to be normally open and to be in a closed position only when the projectile 20 is experiencing a positive - g force of sufficent magnitude . the rear section 44 of the nose 37 houses a proximity fuze circuit 42 and an s & amp ; a 43 that , when activated by circuit 42 , causes detonation of the he charge 48 via a detonator 54 . the switches 39 , 40 and the antenna 41 , electrically connected to the circuit 42 , are imbedded in the section 38 which may be made of molded plastic . fig2 shows a functional block diagram of the fuze 34 . the fuze circuit 42 includes a reserve power supply 50 , a doppler radar 51 , having an enable gate 55 and an internal r - c timer 56 , and an output circuit 52 . the reserve power supply 50 may be a conventional thermal - or liquid - activated device wherein activation would be initiated by accelerations generated when the projectile 20 is fired . the supply 50 will put out a voltage on the line 53 when it is fully activated . any momentary closing of the switch 40 after the power supply 50 is fully active will cause the doppler radar 51 to be enabled via enable gate 55 . when enabled , the radar 51 will begin transmitting and receiving signals via antenna 41 under the power provided by the supply 50 via line 57 . also , the r - c timer 56 will start charging at this time . it is noted that even though the switch 40 may be momentarily closed during the initial firing of the projectile 20 , the radar 51 will not be enabled at this time because the reserve power supply 50 will not yet be fully active . a short time delay , typically about 50 milliseconds , is normally required before full activation of the reserve power supply 50 is acheived . an output line from the doppler radar 51 is directed to the output circuit 52 which can provide the necessary input signal to the s & amp ; a 43 to operate the detonator 54 . operation of the detonator 54 via circuit 52 and s & amp ; a 43 is also possible upon closure of the contact switch 39 . fig3 shows a functional block diagram of the digital time fuze 28 and its associated circuitry . the electrical input terminal 30 of primer 25 is connected to one side of a grounded igniter 59 via a blocking diode 58 . the terminal 30 is further connected to one side of a grounded capacitor 60 and the input of a digital data decoder 62 via a blocking diode 67 . the output of the data decoder 62 is connected to one input of a presettable counter 63 which has a second input connected to the output of a frequency scaler 64 . the input of the scaler 64 is connected to the output of an oscillator 65 . a high positive - g enable switch 66 is connected to the oscillator 65 . the output of the counter 63 is connected to the input of the s & amp ; a mechanism 31 which , in turn , is outputted to a squib 27 for firing the booster charge 32 . fig4 shows a typical input pulse train as a voltage vs . time waveform 70 that would be applied by the gunner to the terminal 30 of the primer 25 to fire the projectile 20 . the waveform 70 begins with a positive , relatively long ( 2 millisecond ) power pulse p that is followed by a series of short positive data pulses d and is terminated with a negative , relatively large trigger impulse t . the pulse p is long enough to produce a significant charge on the capacitor 60 to produce the voltage vcc that is used as a source of power to operate the timer circuit components . as seen in fig3 the oscillator 65 , scaler 64 , counter 63 and squib 64 are all connected to the voltage source vcc and use it for operational power . the series of data pulses d are fed to the decoder 62 which will respond by presetting the counter 63 to a predetermined count that is related to an ignition time which in turn is related to a firing range . the negative impulse t represents a typical trigger pulse for firing igniter 59 via the diode 58 of the primer 25 . the blocking diode 67 will prevent the impulse t from discharging the capacitor 60 and from reaching the input of the decoder 62 . it is noted that the blocking diode 58 blocks the series of positive pulses p , d from reaching the igniter 59 but permits the negative impulse t to fire the igniter 59 . when the igniter 59 is fired , the powder in the powder - charge cup 24 will ignite thereby causing the propellant in the propellant chamber 23 to fire the projectile 20 from the gun ( not shown ). the high acceleration of the projectile 20 at firing will close the switch 66 causing the oscillator 65 to output a clock signal that is scaled down by the scaler 64 before it is applied to the counter 63 as an input counting signal . the counter 63 will increment its count in response to the counting signal as the projectile 20 is traveling along its flight path to the target . if and when the counter 63 reaches full count from its preset condition as inputted by the gunner ( data pulses d ) at firing , the counter 63 will output an arming signal to the s & amp ; a 31 that will fire the squib 27 to ignite the booster charge 32 . it is noted that the switch 66 prevents the oscillator 65 from operating until the projectile 20 is underway down the gun tube . this is a safety feature of the system . ignition of the booster charge 32 will produce a rearwardly directed thrust from the booster cavity 29 and , therefore , a forward motion to the projectile 20 . this forward motion will cause a sufficent positive acceleration of the projectile 20 to momentarily close the switch 40 , thereby enabling the doppler radar 51 via the enable gate 55 . the self - destruct timer 56 is also activated at this point . in a typical firing situation , the gunner would program the counter 63 such that the radar 51 is enabled about one - quarter second before arriving at the target range . with the doppler radar 51 operating , radar signals will be transmitted by the antenna 41 . radar reflections from proximate targets will be received by antenna 41 and fed to radar 51 . radar 51 will now be in a position to detect any frequency - shifted reflections from proximate targets that have a predetermined relative magnitude . if a proximate target is detected , the radar 51 will input the s & amp ; a 43 via the output circuit 52 . at this point , the detonator 54 will ignite the he charge 48 and function the projectile 20 . as a self - destruct safety feature , the radar 51 , via timer 56 , will automatically function the projectile 20 if it has not detected a target within a predetermined time after being enabled . it is also noted that once the reserve power supply 50 is fully active , the projectile 20 will be in a position to function via the switch 39 upon impact with a hard target . to demonstrate the versatility of the present invention , its operation in a variety of situations will now be described . the projectile 20 may be used in several different roles from a ground position such as from a gun mounted in a mobile , ground combat vehicle . the gunner would condition the projectile 20 to operate in a chosen mode at the time of firing , i . e . when the projectile 20 is in the gun and the breech is locked . the projectile 20 may be used in an air - defense role by firing it in a ground - to - air ( air burst ) mode . the gunner would preset the time fuze 28 , via data pulses d , to a time setting which will set off the booster charge 32 , via s & amp ; a 31 and squib 27 , just before ( one - quarter second ) the projectile 20 enters into the target area . the acceleration produced by the initiation of the charge 32 at this time will cause the positive - g switch 40 to momentarily close , thereby enabling the radar 51 at this selected point in the trajectory . once the projectile 20 closes to within a short distance from the target , the radar 51 will sense the target and detonate the he charge 48 . in the event the projectile 20 does not pass sufficently close to the target to function the fuze circuit 42 in a predetermined time ( typically about one - half second ), the internal timer 56 will cause the radar 51 to function the detonator 54 and self - destruct the projectile 20 in flight . when used in an anti - personnel role , the projectile 20 would be fired in a flat trajectory and conditioned to explode in an air burst at the &# 34 ; optimum &# 34 ; standoff for the intended ground target . in this mode , the gunner will preset the time fuze 28 to a setting which would function the charge 32 at the &# 34 ; optimum &# 34 ; standoff for the intended ground target . the resulting acceleration of the projectile 20 due to the time fuze 28 would , at this point , enable the radar 51 and , due to its close proximity to the earth , would immediately function the fuze circuit 42 and hence the he charge 48 in an &# 34 ; air burst &# 34 ; mode . the projectile 20 may also be used in an anti - material role . in this role , the projectile 20 is fired in a flat trajectory and is conditioned to fire on impact . the gunner in this case would provide no time data or would preset the fuze 28 to a setting which is beyond the range of the intended target , and then fire the projectile 20 in a low trajectory directly at the target . since the fuze 28 will not function before reaching the target , the radar 51 will not be enabled . as such , the fuze circuit 42 will function the projectile 20 in response to the closing of the switch 39 when the target is hit . as can be seen from the various modes of operation just described , the invention has a multi - mission capability . the single projectile 20 may be used in a ground - to - air mode , a ground - to - ground ( air burst ) mode and a ground - to - ground ( impact ) mode . the projectile 20 includes a self - destruct feature in the ground - to - air mode . all fuze settings are accomplished an instant before firing directly through the cartridge case 22 . no penetrations into the he cavity 47 from the rear , high - pressure area of the projectile 20 are necessary . although a preferred embodiment of the present invention has been shown and described in detail herein , many other varied embodiments that incorporate the teachings of the present invention may be easily constructed by those skilled in the art . it is therefore to be understood , that the foregoing disclosure and drawings are merely illustrative of the principles of this invention and are not to be interperted in a limiting sense . it is to be understood that the invention should not be limited to the exact details of construction shown and described because obvious modifications will occur to a person skilled in the art .