EP0023365A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Doppler-type projectile velocity measurement apparatus and method
Assignee: Ares Inc
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Filing: 1980-07-31
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Granted: —
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Expires: 2000-07-31
Abstract
Abstract Projectile velocity measurement and communication apparatus comprises a microwave probe fixed to a projectile barrel near a muzzle end. An osciliator, having reference frequency selected for exciting a fundamental electromagnetic mode in the barrel, is connected to the probe through a hybrid mixer configured for extracting, from moving projectile-reflected microwaves, a true Doppler signal having a varying frequency related to projectile barrel velocity. A processor, connected for receiving the Doppler signal, measures, by a clock oscillator, Doppler signal periods (half periods). A data presorter in the processor selects a last "N" number of period measurements before the projectile reaches an interference position relative to the probe, to be fed to a fire control computer interface for determination therein of projectile barrel and muzzle velocities, calibration means being provided to update barrel diameter values used in such determination. An alternative, dual reference fre- , quency variation is described, in which a dual hybrid mixer provides two independent Doppler signals, to eliminate dependency of projectile velocity determinations on barrel diameter. A reference frequency modulator and control means therefor are provided to enable microwave communication of information to the projectile, for example, of projectile target time of flight for fusing purposes. Corresponding methods for projectile velocity measurement and communication are provided.
Inventors
- 👤 Peter P. Toulios
- 👤 Kenneth D. Hartman
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 22:08
CPC Classifications
F; F41; F41A; F41A21/00; F41A21/32; F41G; F41G3/00; F41G3/12; F41G5/00; F41G5/08; F42; F42C; F42C17/00; F42C17/04; G; G01; G01P; G01P3/00; G01P3/64; G01P3/66; G01P3/665; G01S; G01S13/00; G01S13/02; G01S13/50; G01S13/58; H; H01; H01Q; H01Q1/00; H01Q1/44
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
171 words
In a microwave type projectile velocity determining apparatus for a projectile firing weapon, such as a cannon (12), having an elongate projectile guiding barrel (64), characterized in that the velocity determining apparatus comprises a microwave probe (14); means adapted for fixing the probe to the projectile barrel (64) adjacent to a muzzle end (68) thereof with a probe inner end (48) adjacent to, but out of the path of projectiles (72) traveling through the barrel; microwave oscillator means (76) connected to the probe for providing microwave energy thereto for introduction thereby into said barrel, frequency of the oscillator means being selected to excite a fundamental electromagnetic mode in the barrel; mixer means (74) connected to the probe for receiving therefrom microwave energy reflected by the projectile traveling through the barrel and for extracting therefrom a Doppler frequency signal (164) corresponding to projectile barrel velocity; and processor means (80) connected to the mixer means for receiving the Doppler signal therefrom and for obtaining from the Doppler signal the corresponding projectile barrel velocity.
Claim 2
Dependent Claim
171 words
In a microwave type projectile velocity determining apparatus for a projectile firing weapon, such as a cannon (12), having an elongate projectile guiding barrel (64), characterized in that the velocity determining apparatus comprises a microwave probe (14); means adapted for fixing the probe to the projectile barrel (64) adjacent to a muzzle end (68) thereof with a probe inner end (48) adjacent to, but out of the path of projectiles (72) traveling through the barrel; microwave oscillator means (76) connected to the probe for providing microwave energy thereto for introduction thereby into said barrel, frequency of the oscillator means being selected to excite a fundamental electromagnetic mode in the barrel; mixer means (74) connected to the probe for receiving therefrom microwave energy reflected by the projectile traveling through the barrel and for extracting therefrom a Doppler frequency signal (164) corresponding to projectile barrel velocity; and processor means (80) connected to the mixer means for receiving the Doppler signal therefrom and for obtaining from the Doppler signal the corresponding projectile barrel velocity.
Claim 3
Dependent Claim
39 words
The projectile velocity determining apparatus of Claim 1, further characterized in that the processor means (80) includes period counting means (186) for making period measurements of the Doppler frequency signal (164) for determination of the corresponding projectile barrel velocity.
Claim 4
Dependent Claim
84 words
The projectile velocity determining apparatus of Claim 2, further characterized in that the Doppler signal has a varying frequency corresponding to varying projectile velocity in the barrel, and in that the processor means (80) includes means (190, 192) for selecting a predetermined number, N, of the period measurements, corresponding to N barrel positions of an associated projectile in which the projectile approaches relatively closely to the probe (14), said N period measurements being used for determining a corresponding set of N projectile barrel velocities.
Claim 5
Dependent Claim
28 words
The projectile velocity determining apparatus of Claim 3, further characterized in that means (82) are provided for extrapolating a projectile muzzle velocity from said N projectile barrel velocities.
Claim 6
Dependent Claim
43 words
The projectile velocity determining apparatus of Claim 1, further characterized in that means (82) are included for compensating, when obtaining the projectile velocities, for effective barrel diameter changes caused by thermal expansion/contraction and by wear due to passage of projectiles through the barrel.
Claim 7
Dependent Claim
92 words
The projectile velocity determining apparatus of Claim 1, further characterized in that the Doppler signal has a varying frequency related to projectile barrel velocity and the processor means (80) measures half periods of the Doppler frequency signal (164), and in that means (192, 194, 82) are provided for converting only a selected number, N, of the half period measurements associated with projectile movement relatively adjacent to the probe (14) into N corresponding projectile barrel velocities, for smoothing said N projectile barrel velocities and for determining projectile muzzle velocity from said smoothed velocities.
Claim 8
Dependent Claim
161 words
The projectile velocity determining apparatus of Claim 1, further characterized in that the oscillator means includes first and second reference oscillator means (76a, 76b) connected to the probe (14) for providing microwave energy at respective first and second reference frequencies thereto for introduction thereby into the barrel (64), the first and second reference frequencies being selected to excite a fundamental electromagnetic mode in the barrel; in that the mixer means comprises dual mixer means (74a) connected to the probe (14) for receiving therefrom microwave energy reflected by the projectile (72) traveling through the barrel, and for separately extracting therefrom first and second Doppler frequency signals, associated with said first and second reference frequencies and separately corresponding to projectile barrel velocity; and in that the processor means comprises dual processor means (80a) connected to the dual mixer means (74a) for receiving the first and second Doppler frequency signals therefrom and for obtaining from the Doppler frequency signals the corresponding projectile barrel velocity.
Claim 9
Dependent Claim
42 words
The projectile velocity determining apparatus of Claim 7, further characterized in that the dual processor means (74a) includes period counting means (106) for making period measurements of the first and second Doppler frequency signals for determination of the corresponding projectile barrel velocity.
Claim 10
Dependent Claim
140 words
The projectile velocity determining apparatus according to Claim 8, further characterized in that the first and second Doppler signals vary according to varying projectile velocity in the barrel (64), in that the dual processor means (80a) obtains from the first and second Doppler signals a single set of corresponding projectile barrel velocities and the period counting means makes - separate sets of period measurements for the first and second Doppler signal frequencies and in that the processor means includes presorting means (190) for selecting a predetermined number, N, of the period measurements for each said set of period measurements corresponding to N barrel positions of the associated projectile (72) in which the projectile approaches relatively closely to the probe (14), the two sets of N period measurements being used for determining a single corresponding set of N projectile barrel velocities.
Claim 11
Dependent Claim
64 words
The projectile velocity determining apparatus of Claim 9 further characterized in that the first and second reference frequencies are selected to be separated in frequency by about 100 MHz to 300 MHz and in that the dual processor means (80a) determines the single corresponding set of N projectile barrel velocities independently from effects of barrel diameter changes due to thermal expansion/contraction and firing wear.
Claim 12
Dependent Claim
54 words
The projectile velocity determining apparatus of Claim 9, further characterized in that the first and second reference frequencies are selected to be separated in frequency by about 100 MHz to 300 MHz, and in that means (82) are included for extrapolating from the set of N projectile barrel velocities a single projectile muzzle velocity.
Claim 13
Dependent Claim
63 words
The projectile velocity determining apparatus of Claims 1 or 10, further characterized in that means (220, 222, 230) are included for communicating information to said projectile (72) while the projectile is within transmitting range of the probe (14), said communicating means including reference oscillator frequency modulating means (220) for including the information to be communicated to the projectile with the oscillator frequency signal.
Claim 14
Dependent Claim
89 words
The projectile velocity determining apparatus of Claim 12, further characterized in that said communicating means (220, 222, 230) includes means (224) forming an outwardly flared aperture (226) at a muzzle end (228) of the barrel (64) beyond the probe (14), said aperture formi - an antenna for enhancing coupling of microwave energy, emitted into the barrel by the probe, into free space beyond the muzzle end, thereby enhancing capability to com municate information to the projectile (72) after the projectile has exited the barrel and is in free flight.
Claim 15
Dependent Claim
81 words
The projectile velocity determining apparatus of Claim 13, further characterized in that the communicating means (220, 222, 230) includes means (230) for stepping the reference oscillator (76), after the Doppler frequency signal (164) has been received by the processor means (80) and the projectile (72) reaches the probe, (14) from the frequency selected to excite a fundamental electromagnetic mode in the barrel (64) to a second frequency below the barrel cutoff frequency of the fundamental mode, thereby increasing projectile communication range.
Claim 16
Dependent Claim
111 words
In a projectile communicating apparatus for a projectile firing weapon, such as a cannon (12), having an elongate projectile guiding barrel (64), characterized in that the projectile communicating apparatus comprises a microwave probe (14); means adapted for fixing the probe to the projectile barrel (64) with a probe inner end (98) adjacent to, but out of the path of projectiles (72) traveling through the barrel; microwave reference oscillator means (76) connected to the probe for providing microwave energy thereto for introduction thereby into the barrel to which the probe is fixed; and means (220) for selectively modulating the reference oscillator frequency for including therein information to be communicated to the projectile.
Claim 17
Dependent Claim
111 words
In a projectile communicating apparatus for a projectile firing weapon, such as a cannon (12), having an elongate projectile guiding barrel (64), characterized in that the projectile communicating apparatus comprises a microwave probe (14); means adapted for fixing the probe to the projectile barrel (64) with a probe inner end (98) adjacent to, but out of the path of projectiles (72) traveling through the barrel; microwave reference oscillator means (76) connected to the probe for providing microwave energy thereto for introduction thereby into the barrel to which the probe is fixed; and means (220) for selectively modulating the reference oscillator frequency for including therein information to be communicated to the projectile.
Claim 18
Dependent Claim
57 words
The projectile communicating apparatus of Claim 15, further characterized in that frequency of said oscillator means (76) is selected to excite a fundamental electromagnetic mode in the barrel and the modulation means (220) modulates ,the reference oscillator frequency for including therein information to be communicated to the projectile (72) while the projectile is still in the barrel.
Claim 19
Dependent Claim
55 words
The projectile communicating apparatus of Claim 15, further characterized in that the oscillator frequency is selected to be below the barrel cutoff frequency and the modulation means (220) modulates the reference oscillator frequency to include therein information to be communicated to the projectile after the projectile has exited the barrel and is in free flight.
Claim 20
Dependent Claim
86 words
The projectile communicating apparatus of Claim 17, further characterized in that means (224) are included for defining an outwardly flared aperture (226) at a muzzle end (228) of the barrel (64) beyond the probe (14), said aperture forming an antenna for enhancing coupling of the microwave energy, introduced into the barrel by the probe, into free space beyond the muzzle end, thereby increasing the amount of microwave energy radiated outwardly from the barrel in the direction of the projectile and increasing the communication range relative thereto.
Claim 21
Dependent Claim
169 words
In a method for determining projectile velocity in a projectile firing weapon system, such as a cannon (12), having an elongate projectile guiding barrel (64), characterized in that the method comprises the steps of fixing a microwave probe (14) to the projectile barrel (64) adjacent to a muzzle and (68) thereof, with an inner end (98) of the probe adjacent to, but out of the path of, projectiles (72) traveling through the barrel; introducing into the barrel, through the probe (14), microwave energy at a reference frequency selected to propagate a fundamental electromagnetic mode in the barrel; receiving from the barrel, through the probe (14), microwave energy, at a reflected frequency, reflected from a projectile (72) traveling through the barrel; mixing microwave energy at the reference and reflected frequencies and extracting from the reflected frequency a Doppler frequency signal (164) related to projectile barrel velocity and projectile barrel position; and determining from the Doppler frequency signal (164) the related projectile barrel velocity as a function of projectile barrel position.
Claim 22
Dependent Claim
169 words
In a method for determining projectile velocity in a projectile firing weapon system, such as a cannon (12), having an elongate projectile guiding barrel (64), characterized in that the method comprises the steps of fixing a microwave probe (14) to the projectile barrel (64) adjacent to a muzzle and (68) thereof, with an inner end (98) of the probe adjacent to, but out of the path of, projectiles (72) traveling through the barrel; introducing into the barrel, through the probe (14), microwave energy at a reference frequency selected to propagate a fundamental electromagnetic mode in the barrel; receiving from the barrel, through the probe (14), microwave energy, at a reflected frequency, reflected from a projectile (72) traveling through the barrel; mixing microwave energy at the reference and reflected frequencies and extracting from the reflected frequency a Doppler frequency signal (164) related to projectile barrel velocity and projectile barrel position; and determining from the Doppler frequency signal (164) the related projectile barrel velocity as a function of projectile barrel position.
Claim 23
Dependent Claim
54 words
The projectile velocity determining method of Claim 19, further characterized in that the method comprises the additional steps of measuring period lengths of cycles of the Doppler frequency signal (164) and determining, from at least a selected number, N, of measured periods, the related projectile barrel velocity as a function of projectile barrel position.
Claim 24
Dependent Claim
47 words
The projectile velocity determining method of Claim 19, further characterized in that the fundamental electromagnetic mode in the barrel (64) is established by determining an electrically effective barrel diameter and the projectile barrel velocity is determined from the Doppler frequency signal (164) and the effective barrel diameter.
Claim 25
Dependent Claim
46 words
The projectile velocity, determining method of Claim 21, further characterized in that the method includes the step of compensating for changes in effective barrel diameter due to barrel thermal expansion/contraction and barrel wear due to firing before determining projectile barrel velocity from the Doppler frequency signal.
Claim 26
Dependent Claim
178 words
The projectile velocity determining method of Claim 19, further characterized in that the step of introducing microwave energy into the barrel through the probe (14) includes introducing microwave energy at first and second reference frequencies each selected to propagate a fundamental electromagnetic mode in the barrel, as established by determining an electrically effective barrel diameter; in that the step of receiving microwave energy from the barrel through the probe includes receiving microwave energy, at first and second reflected frequencies, related to the first and second reference frequencies, reflected from the projectile (72) traveling through the barrel; in that the step of mixing microwave energy includes mixing microwave energy at said first and second reference and reflected frequencies and separately extracting from the reflected frequencies first and second Doppler frequency signals related to projectile barrel velocity and projectile barrel position; and in that the step of determining projectile velocity includes determining from the first and second Doppler frequency signals the related projectile barrel velocity, as a function of projectile barrel position, independently from effects of the effectii barrel diameter.
Claim 27
Dependent Claim
61 words
' The projectile velocity determining method of Claims 19 or 23, further characterized in that the step of determining related projectile velocity includes determining at least a number, N, of related projectile barrel velocities as a function of projectile barrel position, and in that the method includes the step of extrapolating from the N projectile barrel velocities, a projectile muzzle velocity.
Claim 28
Dependent Claim
43 words
The projectile velocity determining method of Claims 19 or 23, further characterized in that the method includes the step of modulating the microwave energy introduced into the barrel (64), through the probe (14), in a manner enabling communication of information to the projectile.
Claim 29
Dependent Claim
58 words
The projectile velocity determining method of Claim 25, further characterized in that the method includes the step of extrapolating from the barrel velocity a projectile muzzle velocity and a projectile time of flight, and in that the step of communicating information to the projectile includes communicating to the projectile information relating to the extrapolated projectile time of flight.
Claim 30
Dependent Claim
69 words
The projectile velocity determining method of Claim 26, further characterized in that the step of receiving reflected microwave energy from the barrel includes,receiving said energy from a projectile (72) traveling through a partial barrel distance before the projectile reaches the probe (14) preselected to enable determining projectile muzzle velocity and projectile time of flight and communicating time of flight information to the projectile before the projectile reaches the probe.
Claim 31
Dependent Claim
75 words
The projectile velocity determining method of Claim 26, further characterized in that the method includes the step of forming a muzzle end (224) of the barrel (64) into conical, antenna shape, and in that the step of modulating the reference frequency includes modulating the reference signal after the projectile (72) has exited the barrel and is in free flight, the projectile thus being outside the barrel when the time of flight information is communicated thereto.
Claim 32
Dependent Claim
47 words
The projectile velocity determining method of Claim 28, further characterized in that the method includes the step of reducing the reference frequency to a frequenc) below the cutoff frequency of the fundamental mode in the barrel (64) before modulating the signal to communicate with the projectile (72).
Claim 33
Dependent Claim
109 words
In a method for communicating with a projectile in a projectile firing system, such as a cannon (12), having an elongate projectile guiding barrel (64), characterized in that the method comprises the steps of fixing a microwave probe (14) to the projectile barrel (64) adjacent to a muzzle end (68) thereof, with an end (98) of the probe adjacent to, but out of the path of, projectiles (72) traveling through the barrel; introducing into the barrel (64), through the probe (14), microwave energy having a reference frequency selected to propagate a fundamental mode in the barrel; and modulating the reference frequency in a manner enabling communication with the projectile.
Claim 34
Dependent Claim
109 words
In a method for communicating with a projectile in a projectile firing system, such as a cannon (12), having an elongate projectile guiding barrel (64), characterized in that the method comprises the steps of fixing a microwave probe (14) to the projectile barrel (64) adjacent to a muzzle end (68) thereof, with an end (98) of the probe adjacent to, but out of the path of, projectiles (72) traveling through the barrel; introducing into the barrel (64), through the probe (14), microwave energy having a reference frequency selected to propagate a fundamental mode in the barrel; and modulating the reference frequency in a manner enabling communication with the projectile.
Claim 35
Dependent Claim
34 words
The projectile communication method of Claim 30, further characterized in that the step of introducing microwave energy into the barrel includes selecting the microwave frequency to be below the fundamental mode of the barrel.
Claim 36
Dependent Claim
59 words
The projectile communication method of Claim 31, further characterized in that the method includes the step of forming a muzzle end (224) of the barrel (64) into a conical antenna shape for enhancing coupling of microwave energy from the barrel into free space beyond the barrel to enable communication with the projectile after the projectile has left the barrel.
Claim 37
Dependent Claim
31 words
The projectile communication method of Claim 30, further characterized in that the step of modulating the reference frequency enables communication with the projectile while the projectile is still in the barrel.
References Cited (Backward Citations)
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