Title:
Missile altitude sensing system
United States Patent 3867843


Abstract:
A non-rotating sphere is floated on a spherical air film. Provision is made for a double pneumatic integration of the vertical component of acceleration to indicate the desired missile arming altitude. A control output signal is then generated at the predetermined altitude and used to arm the missile or otherwise control it in its operation.



Inventors:
MCKENNEY HENRY F
Application Number:
04/810389
Publication Date:
02/25/1975
Filing Date:
03/25/1969
Assignee:
CHRYSLER CORPORATION
Primary Class:
Other Classes:
73/503
International Classes:
G01C5/00; G01P7/00; (IPC1-7): G01C21/16
Field of Search:
102/70.2,81 73
View Patent Images:
US Patent References:
3302466Accelerometer1967-02-07Ogren
3276270Combined gyroscope and accelerometer1966-10-04Speen
3080761Accelerometer1963-03-12Speen
2958279Torpedo arming device1960-11-01Haberland



Primary Examiner:
Pendegrass, Verlin R.
Attorney, Agent or Firm:
Talburtt & Baldwin
Claims:
I claim

1. An altitude sensing system for a missile during its boost phase comprising a spherical shell, a hydrostatic perforated bearing structure enclosing said shell, a gas pressure source for providing high pressure flow through said bearing structure to support said shell on a pressurized gas film, a first integrating chamber of said shell, a second integrating chamber of said shell formed interior of said first chamber, a first pair of integrating orifices formed in said first chamber along the longitudinal axis of said missile, one at the upper and the other at the lower end of said first chamber, said first pair of orifices communicating between said gas film and the interior of said first air chamber, a second pair of integrating orifices aligned along said axis at opposite ends of said second chamber, said second pair of orifices communicating between said second chamber and said first chamber, respectively, and a differential pressure sensing means mounted in said second chamber for providing a control output signal responsive to a pressure differential representative of predetermined missile displacement.

2. The combination as set forth in claim 1 wherein said shell comprises a porous structure of two hemispheric parts each electrically insulated from the other and a firing device is connected to said differential pressure sensing means for shorting said parts together and providing an electrical output signal.

3. The combination as set forth in claim 1 wherein a seismic shock responsive device is operating connected to and responsive to said firing device for providing said control output signal.

4. An altitude sensing system for a missile during its boost phase comprising a spherical shell, a hydrostatic bearing structure of porous material enclosing said shell, a gas pressure source connectible to said bearing structure for providing a high pressure gas flow through said bearing structure to support said shell on a pressurized gas film, an exhaust manifold connected to a plurality of return conduits formed in said bearing structure to exhaust a portion of said gas, a first integrating chamber formed in said shell, a second integrating chamber formed in said shell and enclosed by said first chamber, a north and a south polar orifice formed in each of said chambers, said orifices lying along the missile thrust axis, and a differential pressure sensing means mounted within said second chamber and responsive to a differential in pressure existing between its two ends to provide a control output signal representative of a predetermined magnitude of missile displacement.

5. A displacement responsive system for an object movable in a linear path comprising a spherical shell, a hydrostatic bearing structure containing said shell, a gas pressure source connectable at a number of points to said bearing structure for providing a high pressure flow therethrough for supporting said shell on a pressurized gas film, a second spherical shell mounted in said first spherical shell and concentric therewith, planar means passing through both of said shells at their centers normal to said path to divide each into substantially equal hemispheric portions, each of said portions having an upper and a lower orifice lying along said path, a differential pressure sensing means mounted in said second shell between its two hemispheric portions and operable to provide an output signal responsive to the movement of said object over a predetermined distance.

6. A displacement responsive system for an object movable in a linear path comprising a first spherical shell, a hydrostatic bearing structure containing said shell, a gas pressure source connectible at a plurality of points to said bearing structure for providing a high pressure flow therethrough for supporting said first shell on a pressurized gas film, a second spherical shell mounted in said first spherical shell, concentric therewith and spaced therefrom, each of said shells having an upper and a lower integrating orifice, said orifices lying along said path, and a differential pressure means mounted in said second spherical shell and responsive to a predetermined magnitude of the differential pressure to provide an output signal representative of distance traveled.

Description:
BACKGROUND OF THE INVENTION

The field to which my invention relates is that of missiles operating in a boost phase mode. The initial launching direction is vertical with ground commanded flight direction. My altitude sensing system meets the requirements of simple and reliable construction, long shelf life, freedom from necessity for pre-flight checkout and operation in a severe environment. The system incorporates a floating sphere thus allowing only vertical acceleration to be sensed independently of the missile attitude or position.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a vertical half-sectional view of my invention with parts shown in partial diagrammatic form to clarify its operation; and

FIG. 2 shows an alternate embodiment of the arming device of invention as incorporated in the basic structure of FIG. 1.

DESCRIPTION

FIG. 1 shows the detail of construction of my pneumatically suspended integrated altitude sensing device. An outer shell 10 has connected to it a high pressure regulated source 12. Air flow is provided through manifold 14 as indicated by the arrows. Upper and lower caging pins 16, 18, are released by the flow of air from pressure source 12. The detail of a suitable cage release mechanism is shown in connection with upper caging pin 16. The inrush of pressurized air deflects diaphragm 20 to its upper dash line position to move pin 16 upwardly thus permitting the inner spherical elements of the device to float freely on a layer of pressurized air. This supporting air layer or film is denoted by the numeral 22. A uniform distribution of pressurized air is passed from manifold 14 to layer 22 through a porous or randomly perforated shell 24.

The floating elements include outer spherical shell 26 and inner spherical shell 28. These two shells define between them top and bottom first chambers 30a and 30b. Inner shell 28 further is divided into upper and lower chambers 32a and 32b. Upon the release of caging pins 16 and 18, integrating orifices 34a, 34b are opened to permit passage of air therethrough. Under acceleration, the inertial mass of shells 26 and 28 which are supported on the pressurized air film deflects. This deflection causes the metering of the flow of air differently through upper and lower orifices 34a and 34b. The differential pressure build up between chambers 34a, 34b represents the first integral of acceleration with respect to time i.e., velocity. Additionally, in the flow of air through the second set of orifices 36a, 36b, a second integration process is performed. A differential pressure transducer 38 is shown mounted between chambers 32a and 32b. This transducer may be embodied for example as a squib which is actuated when the differential pressure reaches a predetermined magnitude. This will serve to provide a control signal output which is utilized in a manner well known in the art to arm the missile warhead or otherwise exercise control over the missile. To generate this signal, a pick-up 40 may be employed in the system to sense the seismic shock of the squib and respond thereto.

FIG. 2 is a schematic showing of an alternate embodiment of my invention in which a different type of transducer is used to generate a control output signal suitable to arm the missile. In this form of my invention, the triggering may be accomplished by a toggle-action device or oil can type trigger as is shown. The upper and lower diaphragms 41a, 41b are deflectable to their respective dashed line positions to detonate a squib 42 through firing pin 43. Responsive to the firing of squib 42a pair of plungers 44, 45 are driven in opposite directions. Porous shell 24 in this case is formed in an upper and a lower hemisphere, each electrically insulated from the other by an insulating ring 46 of the cross-sectional configuration shown. Plungers 44, 45 thus serve to short the insulated upper and lower halves together and provide an electrical output signal for arming the missile warhead.

DESCRIPTION OF OPERATION

The missile is provided with a launch force along its thrust axis as designated by the arrow A of FIG. 1. Concurrent with the firing of the missile, the air from high pressure source 12 is released through outer manifold 14 to uncage pins 16 and 18 which pins extend through porous shell 24 to maintain a layer or film 22 of pressurized air. Shell 24 has the ability of maintaining a definitive orientation since it is non-rotating and is supported by a virtually frictionless air film to minimize drag. Because of the spherical shape of shell 26, it allows up to 360° of freedom of missile movement (about three axes) without adversely affecting the basic sensor function. For the shell 24 to be supported, it is necessary for the static pressure on the lower hemisphere to average higher than that on the upper hemisphere. In the undeflected condition, the air flow is along the meridian, separating at the equator toward orifice 34a in a northerly orientation and toward orifice 34b in a southerly orientation.

When an axial deflection occurs at launch, the flow is still along the meridian but with a wider gap between the upper hemisphere of shell 26 and porous shell 24 than between the lower hemisphere of shell 26 and porous shell 24. Accordingly, a greater flow volume will reach upper orifice 34a than lower orifice 34b. As the lower gap closes down under the loading, the static pressure rises approaching a significant fraction of the pressure of outer manifold 14 while the velocity becomes relatively slow. The dividing line of the northerly and southerly portions of the flow field will move to the southern latitudes so that upper orifice 34a will be supplied by air influxing over a larger area of porous shell 24. Over the region where the deflection of the flow dividing line is proportioned to "g" loading, the differential flow into first chambers 30a, 30b will also be proportional to g loading. If the flow through upper and lower orifices 34a, 34b is essentially independent of downstream pressure, the differential pressure of chambers 30a, 30b will represent missile vertical velocity. If orifices 36a, 36b admitting air to second chambers 32a, 32b are made small enough, we have the required condition that flow is essentially independent of downstream pressure. The differential pressure between the second chambers 32a, 32b provides a good representation of the inertial displacement of the missile in the vertical direction. When this differential pressure reaches a predetermined magnitude, the transducer 38 of FIG. 1 will provide an output signal from pickup 40 responsive to firing of a squib. In the modification of FIG. 2, the upper and lower insulated sections of shell 24 are shorted together responsive to the firing of squib 42 and the operation of plungers 44, 45.

It will be appreciated that in some cases the volume of air required for flotation of the shells will be too large to be accommodated in the integration chambers without using excessive pressure. The structure will then be modified to provide that only a portion of the flotation air in layer 22 will be passed to the integrating orifices. The remainder will be exhausted externally through small distributed orifices back through perforated shell 24 to an exhaust manifold. The integrating orifices would be multiple in order to average out the effect of individual input and exhaust openings.