US4792804A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for detecting a body in motion on the ground of a protected area
Assignee: DEI Dispositivi Elettronici Industriali di Rubechini Roberto
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Filing: 1987-05-01
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Granted: 1988-12-20
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Expires: 2007-05-01
Abstract
Abstract An apparatus for detecting bodies in motion on the ground of a protected area, particularly for military use and the like, wherein, by means of an antenna buried and shielded from the air, an electromagnetic signal in the range of radio frequency is radiated into the ground. Receiver means comprising means for detecting variations of the signal intensity are placed at a known distance from the receiving antenna. The intensity variation is dependent on the presence of bodies in motion within the range of action of the apparatus.
Inventors
- 👤 Roberto Rubechini
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:22
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/12
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
135 words
Apparatus for detecting a body in motion on the ground of a protected area, comprising: (a) transmitter means for transmitting radio frequency elctromagnetic signals including at least a fully buried transmitting antenna, shielded for inhibiting a radio frequency radiation in the air; (b) receiver means for receiving said signals including at least a receiving antenna fully shielded to the air and placed at a known distance from said transmitter means; (c) automatic gain control means coupled to said receiver means for adjusting the sensitivity thereof to an average level of an input signal; (d) detector means for detecting amplitude variations of the input signal, for driving said automatic gain control means and for discriminating fast variations due to a body in motion on the ground from slow variations due to physical effects in the ground.
Claim 2
Dependent Claim
135 words
Apparatus for detecting a body in motion on the ground of a protected area, comprising: (a) transmitter means for transmitting radio frequency elctromagnetic signals including at least a fully buried transmitting antenna, shielded for inhibiting a radio frequency radiation in the air; (b) receiver means for receiving said signals including at least a receiving antenna fully shielded to the air and placed at a known distance from said transmitter means; (c) automatic gain control means coupled to said receiver means for adjusting the sensitivity thereof to an average level of an input signal; (d) detector means for detecting amplitude variations of the input signal, for driving said automatic gain control means and for discriminating fast variations due to a body in motion on the ground from slow variations due to physical effects in the ground.
Claim 3
Dependent Claim
13 words
Apparatus according to claim 1, wherein said electromagnetic signals comprise a continuous wave.
Claim 4
Dependent Claim
14 words
Apparatus according to claim 2, wherein said electromagnetic signals have a coded variable frequency.
Claim 5
Dependent Claim
17 words
Apparatus according to claim 3, wherein the frequency range of said signals is 0.6 to 900 MHz.
Claim 6
Dependent Claim
14 words
Apparatus according to claim 2, wherein said electromagnetic signals have a coded fixed frequency.
Claim 7
Dependent Claim
16 words
Apparatus according to claim 5, wherein said electromagnetic signals have a radio frequency of 200 MHz.
Claim 8
Dependent Claim
14 words
Apparatus according to claim 1, wherein said transmitting antenna is a half-wave dipole stile.
Claim 9
Dependent Claim
36 words
Apparatus according to claim 1, wherein said detector means comprise a derivator circuit for discriminating in the detected signal fast variations due to bodies in motion from slow variations due to physical effects of the ground.
Claim 10
Dependent Claim
28 words
Apparatus according to claim 1, wherein said electromagnetic signals are coded, said transmitter means comprising a signal coding circuit, and said receiver means comprising a signal decoding circuit.
Claim 11
Dependent Claim
15 words
Apparatus according to claim 1, wherein said transmitter means comprise a plurality of transmitting antennas.
Claim 12
Dependent Claim
11 words
Apparatus according to claim 10, wherein said transmitting antenna is omnidirectional.
Claim 13
Dependent Claim
18 words
Apparatus according to claim 10, wherein said transmitting antenna is directional and comprises an assembly of elementary antennas.
Claim 14
Dependent Claim
15 words
Apparatus according to claim 1, wherein said receiver means comprise a plurality of receiving antennas.
Claim 15
Dependent Claim
20 words
Apparatus according to claim 1, further comprising processor means for an analysis and comparison of the data detected in reception.
Claim 16
Dependent Claim
16 words
Apparatus according to claim 1, further comprising power supply means for said transmitter and receiver means.
Claim 17
Dependent Claim
15 words
Apparatus according to claim 1, further comprising means for remote transmission of the detected data.
Claim 18
Dependent Claim
39 words
Apparatus according to claim 1, including a measurement device for measuring the humidity level of the ground connected to said transmitter means to adjust the amplitude of the output signal from said transmitter means responsive to the measured humidity.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-12-20 | 1992-06-20 | 1992-12-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-20 | 1996-06-20 | 1996-12-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-20 | 2000-06-20 | 2000-12-20 | $7700.00 | Window Closed / Lapsed |