U.S. patent application number 12/911964 was filed with the patent office on 2012-08-23 for fuze internal oscillator calibration system, method, and apparatus.
This patent application is currently assigned to AAI Corporation. Invention is credited to Chris Bevard, Richard Paul Oberlin.
Application Number | 20120210858 12/911964 |
Document ID | / |
Family ID | 46651652 |
Filed Date | 2012-08-23 |
United States Patent
Application |
20120210858 |
Kind Code |
A1 |
Bevard; Chris ; et
al. |
August 23, 2012 |
FUZE INTERNAL OSCILLATOR CALIBRATION SYSTEM, METHOD, AND
APPARATUS
Abstract
A system, apparatus, and method for detonating a projectile
which includes receiving data by a microprocessor located in the
projectile from an external ballistic computer. Calibrating a low
frequency oscillator located in the projectile using an internal
precision reference oscillator also located in the projectile that
can withstand launch accelerations of tens of thousands of g's.
Powering off the reference oscillator when calibration is complete
to save energy and transmitting a detonation signal from the
microprocessor to a detonation circuit located in the
projectile.
Inventors: |
Bevard; Chris;
(Cockeysville, MD) ; Oberlin; Richard Paul;
(Phoenix, MD) |
Assignee: |
AAI Corporation
Hunt Valley
MD
|
Family ID: |
46651652 |
Appl. No.: |
12/911964 |
Filed: |
October 26, 2010 |
Current U.S.
Class: |
89/6 ; 102/210;
102/215 |
Current CPC
Class: |
F42C 11/002 20130101;
F42C 11/065 20130101; F42C 17/04 20130101 |
Class at
Publication: |
89/6 ; 102/215;
102/210 |
International
Class: |
F42C 17/04 20060101
F42C017/04; F42C 19/12 20060101 F42C019/12 |
Claims
1. A self contained fuze apparatus comprising: a power supply; a
power conditioner electrically coupled to said power supply; a
microprocessor coupled to said power conditioner; a first
oscillator coupled to said microprocessor; a reference oscillator
coupled to said microprocessor, wherein said reference oscillator
is operable to directly calibrate said first oscillator; and a
detonation circuit coupled to said microprocessor, said detonation
circuit coupled to said power conditioner.
2. The fuze apparatus of claim 1, further comprising a
microcontroller located in a projectile, wherein said
microcontroller comprises: said power conditioner; said
microprocessor; said first oscillator; said reference oscillator;
and said detonation circuit.
3. The fuze apparatus of claim 1, wherein said reference oscillator
is capable of operating within 1 to 200 milliseconds of receiving
power.
4. The fuze apparatus of claim 1, wherein said reference oscillator
is capable of withstanding launch accelerations of tens of
thousands of g's.
5. The fuze apparatus of claim 1, wherein said reference oscillator
comprises a low frequency oscillator.
6. The fuze apparatus of claim 1, further comprising: a low
frequency oscillator coupled to said microprocessor, wherein said
reference oscillator is a high frequency oscillator coupled to said
microprocessor.
7. The fuze apparatus of claim 1, wherein said reference oscillator
includes an enable function operable by said microprocessor.
8. The fuze apparatus of claim 1, further comprising: a power
switch electrically coupled to said reference oscillator, wherein
said power switch is operable by said microprocessor.
9. The fuze apparatus of claim 6, wherein said low frequency
oscillator oscillates at a frequency less than or equal to 100
KHz.
10. The fuze apparatus of claim 6, wherein said high frequency
oscillator oscillates at a frequency greater than 100 KHz.
11. The fuze apparatus of claim 6, wherein said low frequency
oscillator and said first oscillator are resistor-capacitor (RC)
oscillators.
12. The fuze apparatus of claim 1, wherein said reference
oscillator comprises an all silicon resonator.
13. The fuze apparatus of claim 1, wherein said power supply
comprises a piezoid power source.
14. The fuze apparatus of claim 1, wherein said power supply
comprises a battery power source.
15. The fuze apparatus of claim 1, wherein said power supply
comprises a external circuit.
16. The fuze apparatus of claim 1, wherein said reference
oscillator is operable on a separate circuit from said
microprocessor.
17. A system of detonating a projectile comprising: a ballistic
computer; a microcontroller located on said projectile, said
microcontroller comprising: a microprocessor operable to receive
detonation timing data from said ballistic computer; a low
frequency oscillator coupled to said microprocessor; a reference
oscillator operable to calibrate said low frequency oscillator; a
detonation circuit coupled to said microprocessor.
18. The system of claim 16, wherein the microcontroller further
comprises: a power switch electrically coupled to a power supply,
said power switch coupled to said microprocessor, said power switch
electronically coupled to said reference oscillator, wherein said
microprocessor is operable to disconnect power from said reference
oscillator.
19. The system of claim 16, wherein said reference oscillator
comprises an enable function operable by said microprocessor.
20. A method, comprising: receiving ballistic data by a
microprocessor from a ballistic computer, wherein said
microprocessor is internal to a projectile and said ballistic
computer is located external to the projectile in a Fire Control
System (FCS); calibrating a low frequency oscillator coupled to
said microprocessor via a reference oscillator located in said
projectile, wherein said low frequency oscillator is operable to
withstand launch accelerations of tens of thousands of g's;
powering off said reference oscillator upon completion of said
calibrating; and transmitting from said microprocessor a detonation
signal to a detonation circuit.
21. The method according to claim 19, further comprising: enabling
said reference oscillator by said microprocessor, wherein said
reference oscillator includes an enable function operable by said
microprocessor.
Description
RELATED ART
[0001] This application is related to U.S. Pat. No. 5,942,714, to
Richard Oberlin and Robert Soranno, titled Accurate Ultra Low Power
Fuze Electronics, assigned to the AAI Corporation, Hunt Valley Md.,
the contents of U.S. Pat. No. 5,942,714 are hereby incorporated
herein in their entirety by reference.
BACKGROUND
Field of the Invention
[0002] The present invention relates generally to a new and
improved fuze design to simplify the interface between the fuze
electronics and the fire control system.
SUMMARY
[0003] In an embodiment of the present invention, a self contained
fuze apparatus is disclosed. This embodiment includes a power
supply, a power conditioner electrically connected to the power
supply, a microprocessor connected to the power conditioner, an
oscillator connected to the microprocessor, a reference oscillator
connected to the microprocessor, and a detonation circuit connected
to the microprocessor and the power conditioner. In this
embodiment, the reference oscillator directly calibrates the
oscillator.
[0004] In another embodiment of the present invention, a projectile
detonation system is disclosed. This embodiment includes a
ballistic computer, a projectile, and a microcontroller located on
the projectile. In this embodiment, the microcontroller includes a
microprocessor, a low frequency oscillator, a reference oscillator,
and a detonation circuit. In this embodiment, the Microprocessor is
capable of receiving detonation timing data from the ballistic
computer and is connected to the low frequency oscillator and the
detonation circuit. In this embodiment, the reference oscillator is
capable of calibrating the low frequency oscillator.
[0005] In yet another embodiment of the present invention, a method
includes: receiving data by an internal microprocessor from an
external ballistic computer, where the microprocessor is located in
said projectile and the ballistic computer is located external to
the projectile in a Fire Control System (FCS); calibrating an
internal low frequency oscillator coupled to the microprocessor via
an internal reference oscillator located in the projectile, where
the low frequency oscillator can withstand launch accelerations of
tens of thousands of g's; powering off the reference oscillator on
completion of calibration; and transmitting from the microprocessor
a detonation signal to a detonation circuit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 depicts an illustrative block diagram of a fuze
internal oscillator calibration system with an exemplary power
switch;
[0007] FIG. 2 depicts an illustrative block diagram of a fuze
internal oscillator calibration system with an exemplary enable
function;
[0008] FIG. 3 depicts an illustrative block diagram of a fuze
internal oscillator calibration device powered by the
microprocessor;
[0009] FIG. 4 depicts an illustrative block diagram of a known fuze
external oscillator calibration device; and
[0010] FIG. 5 depicts an illustrative block diagram of a fuze
internal oscillator calibration system.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION
[0011] An illustrative embodiment of the invention is discussed in
detail below. While specific illustrative embodiments are
discussed, it should be understood that this is done for
illustration purposes only. A person skilled in the relevant art
will recognize that other components and configurations can be used
without parting from the spirit and scope of the invention.
[0012] An illustrative embodiment of the invention relates
generally to a new and improved fuze design used to detonate
munitions. The fuze circuit may be disposed in a projectile that
requires accurate detonation timing. In one embodiment, an internal
fuze (i.e., internal to the projectile) may be used in, for
example, 50 caliber and larger (e.g., but not limited to, up to 155
mm) projectiles. External to the projectile, a Fire Control System
(FCS) may be used to determine the desired range for the fuze to
optimally detonate the projectile. Once the desired range is
determined, the time to detonation from launch may be calculated.
The required data may be transferred from the external FCS to the
internal fuze of the projectile. The data can be of a variety of
types depending on the weapon it is installed in. The data type can
be, for example, Mode, Target Range, Event Time, diagnostics, or
Ballistic Data.
[0013] The internal fuze may utilize an internal microprocessor
which may process data and, based on the data, detonate the
accompanying projectile at the appropriate time and distance from
launch.
[0014] FIG. 4. depicts a block diagram of a known fuze external
oscillator calibration device. Data 430 processed by the ballistic
computer 435 is transferred to a required modulator 425. Output
from an external precision high frequency oscillator 445 is also
sent to the modulator 425. Data then travels over the data link 420
to the microprocessor 410 to calibrate a high frequency oscillator
405. The microprocessor 410 of the fuze electronics 485 is
preprogrammed with the precise frequency of the external FCS
oscillator 445.
[0015] Thus, any oscillators internal to the fuze and projectile
must be calibrated from a source external to the fuze and
projectile and are therefore, not directly calibrated. As a result
of the need to convey or preprogram the exact frequency from the
FCS 445 to the microprocessor 410, there is a one-to-one
relationship between the fuze electronics 485 and the FCS 450. In
other words, a particular internal fuze electronics 485 only works
with a particular FCS 450.
[0016] An illustrative embodiment of the internal oscillator
calibration of the current invention may eliminate the dependence
on having to convey or preprogram the precise frequency of the
external FCS oscillator parameters into the internal fuze.
[0017] FIG. 1 depicts an illustrative block diagram of a fuze
internal oscillator calibration system with an exemplary power
switch 155.
[0018] In an exemplary embodiment, DC power from power source 105,
is initially routed to power conditioner and storage component 160.
The DC power source 105 may be attained, for example, via a piezo
power source, a battery, an external circuit, or other means to
supply electric current. The DC power source 105 may vary in
current and voltage and the power conditioner and storage component
160 may be used to supply a constant and steady source of power
even after the power source 105 stops supplying power. For example,
the power conditioner and storage component 160 may store and
condition a charge from the power source 105 (e.g., but not limited
to a piezoid power source) at the time of projectile launch and
acceleration. Alternatively, power may be obtained when a
projectile containing the fuze is initially placed in a weapon
breech or gun barrel (not shown). The particular storage capacitor
160 used, is a function of the DC Power Voltage (Vcc) being
supplied, how long the projectile has to operate, and the volume
available.
[0019] Conditioned power may be supplied to the microprocessor 110,
the power switch 155, and the detonator 145. In one embodiment, the
microprocessor 110, via a control port 130, may enable and/or
disable power to the precision reference oscillator 115 through the
use of the power switch 155.
[0020] In one embodiment of the current invention, a sacrificial
reference oscillator such as the precision reference oscillator 115
is used for calibration. The sacrificial reference oscillator may
be considered internal as it is part of the fuze and may be
launched with the projectile. The precision reference oscillator
115 may calibrate either the high frequency oscillator 120 or the
low frequency oscillator 125, the oscillators 120, 125 may, for
example, be of a resistor-capacitor (RC) type oscillator. The
oscillators 120, 125 may be of any type, for example, that can
survive the high launch g's, be stable for a matter of several
seconds and draw low power. Thus, the microprocessor 110 and/or
oscillators 125, 120 may be directly calibrated (i.e., calibrated
internally to the fuze) via the precision reference oscillator 115.
Precision reference oscillator 115 could be the only oscillator
required if it could meet the criteria listed above, but such an
oscillator has not yet been developed.
[0021] The precision reference oscillator 115 may only be powered
on for a short time (e.g., but not limited to, 1 to 200
milliseconds), if the precision reference oscillator 115 current
draw exceeds the available power (e.g., when the precision
reference oscillator 115 operates at a high frequency). A
sufficiently accurate, for example, +/-0.05% or better, oscillator
may be required for proper calibration. In one embodiment, the
precision reference oscillator 115 may not need to survive a high
g-force environment since the calibration may take place prior to
projectile acceleration and a common crystal oscillator may be
sufficient for the precision reference oscillator 115.
[0022] However, in another embodiment, the precision reference
oscillator 115 may be required to survive in a high g-force
environment. Although commonly used crystal oscillators may have
sufficient accuracy, it may be impractical for a crystal oscillator
to be used as the precision reference oscillator 115. Crystal
oscillators may not survive launch accelerations of tens of
thousands of g's. High speed projectiles, especially those with a
piezo power source 105, may require the precision reference
oscillator 115 to remain operational during accelerations of tens
of thousands of g's. With a piezo powered projectile, there may be
no voltage available until the projectile begins accelerating.
Further, the precision reference oscillator 115 may require
operation within milliseconds (e.g., but not limited to, 1 to 200
milliseconds) so that the microprocessor 110 can be programmed
early in the firing cycle. Small size and weight may also be
important for the precision reference oscillator 115 because of
limitations imposed by the size of the projectile and the attendant
fuze cavity.
A table illustrating an exemplary Event vs. Time is shown
below:
TABLE-US-00001 Event Time (1) Projectile placed in Breech Dependent
on the Scenario (2) Target Acquired Dependent on the Scenario (3)
Target Data sent to FCS When Target is Acquired (4) FCS calculates
Time to Detonate Continuously (5) Power applied to Fuze During 0 to
20 ms (6) Lo Frequency Oscillator Calibration During power-up (7)
Hi Frequency Oscillator turned Off 20 ms point (8) Data sent from
FCS to Fuze During 20 to 35 ms (9) Data Verification back to FCS
During 35 to 50 ms (10) Trigger Pulled Time 50 ms (11) Projectile
Fired 50 ms (12) Microproc. sends signal to Detonator From 50 ms to
seconds (13) Projectile high explosive (HE) explodes
[0023] Recently available silicon reference oscillators can survive
tens of thousands of g's and the calibration may be concluded
before the oscillator fails, mechanically, even if levels above
tens of thousands of g's are reached. Several exemplary silicon
oscillators that may be used include the CWX813-16.0M oscillator
manufactured by Connor Winfield Corp., the FXO-HC735-16MHz
oscillator manufactured by Fox Electronics, the
KC2520B25.0000C2GE00 oscillator manufactured by AVX Corp., DSC1030
oscillator manufactured by Discera, Inc., the C3392-16.0000
oscillator manufactured by Crystek Corp., and the EMK22H2H-20.000M
oscillator manufactured by Ecliptek Corp.
[0024] Calibration information from the precision reference
oscillator 115 may travel from the precision reference oscillator
115 via an output port 140 to an input port 135 on the
microprocessor 110. In one embodiment, the precision reference
oscillator 115 calibrates the high frequency oscillator 120, the
high frequency oscillator 120 may then calibrate the low frequency
oscillator 125. In another embodiment, the precision reference
oscillator 115 directly calibrates the low frequency oscillator
125. In another embodiment, the high frequency oscillator 120 and
the low frequency oscillator 125 may be one element.
[0025] For precise fuze detonation, the low frequency oscillator
125 may require accurate calibration to +/-0.1% or better. The low
frequency oscillator 125 typically operates at a low enough
frequency to enable the circuit to draw low enough current so that
it may operate from the power stored in the power conditioner and
storage component 160 even after no power is supplied from DC power
source 105. On the other hand, the high frequency oscillator 120
may operate at a frequency in the MHz region.
[0026] The microprocessor, 110 may calculate the appropriate time
to detonate, at which point, the microprocessor 110 may send a
detonation command from, for example, port 3 150 to the detonation
circuit 145.
[0027] FIG. 2 depicts an illustrative block diagram of a fuze
internal oscillator calibration system with an exemplary enable
function. In one embodiment, the precision reference oscillator 215
includes an "enable" function which may allow the microprocessor
210 to enable the precision reference oscillator 215 either before
the launch of the accompanying projectile or just after the
projectile begins accelerating. For example, port 1 230 of the
microprocessor 210 may be used to send an enable signal to the
precision reference oscillator 215 port 205. The power source 105
may supply power to the power conditioner and storage component
160. Power from the power conditioner and storage component 160 is
not drawn by the precision reference oscillator 215, for example,
until the precision reference oscillator 215 is enabled by the
microprocessor 210.
[0028] FIG. 3 depicts an illustrative block diagram of a fuze
internal oscillator calibration device directly powered by the
microprocessor. In one embodiment, if the precision reference
oscillator 315 current requirement is low enough, the
microprocessor 310, via microprocessor port 330, may supply the
power to the precision reference oscillator 315, via oscillator
connection 305. In one embodiment, the microprocessor 310 may use
the precision reference oscillator 310 for calibration. In another
embodiment, the precision reference oscillator 315 may calibrate an
oscillator 325 which may be electrically coupled to the
microprocessor 310. The oscillator 325 may operate at a single
frequency between, for example, somewhere in the range of, for
example, 1 KHz to 20 KHz.
[0029] FIG. 5 depicts an illustrative block diagram of a fuze
internal oscillator calibration system. Once the projectile 590 is
loaded into the breech of a weapon or weapons system (not shown) or
gun barrel (not shown), data 530 may be received by the ballistic
computer 535 in the FCS 550. Data 540 is then transmitted from the
ballistic computer 535 to microprocessor 510 without the need for
conveying or preprogramming precise oscillator values from the FCS
550 to the fuze electronics 585. The microprocessor 510 is part of
the fuze electronics 585 which is part of the projectile 590. The
power supplied by power source 105 may be from a piezoid, a
battery, an external circuit, or any other known power source.
Power source 105 supplies power to the power conditioner and
storage component 160. With steady power supplied by the power
conditioner and storage component 160, the precision oscillator 515
may calibrate oscillator 520. The oscillator 520 may independently
operate within, for example, the below the 100 kHz range.
Oscillator 520 may be in the same or different circuit as
microprocessor 510.
[0030] When the appropriate length of time has expired,
microprocessor 510 issues a detonation signal to the detonation
circuit 145. The detonation circuit 145 detonates explosive 560
causing the projectile 590 to explode. Various actions can take
place such as a warhead exploding, release of a payload, etc. HE is
normally activated because its action is rapid. The projectile may
also have a default mechanism (not shown) for triggering detonator
145 in the event of a malfunction within the fuze electronics
585.
[0031] While various embodiments of the present invention have been
described above, it should be understood that they have been
presented by way of example only, and not limitation. The sizes and
ranges may change depending on the various embodiments of the
invention. For example, the rate of oscillation of the reference
oscillator 115 may change depending on the weapon and type of
projectile used (e.g., the fuze electronics used for a 50 caliber
round may be different from a 155 mm round). Thus, the breadth and
scope of the present invention should not be limited by any of the
above-described illustrative embodiments, but should instead be
defined only in accordance with the following claims and their
equivalents
* * * * *