US4050067A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Airborne microwave path modeling system
Assignee: Individual
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Filing: 1976-04-21
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Granted: 1977-09-20
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Expires: 1996-04-21
Abstract
Abstract An airborne geophysical measurement and recording system and apparatus in which radar signals are focused onto terrain below an aircraft flying in a straight line between microwave tower sites. The echo signals are detected and signals produced and recorded on a strip chart recorder indicating path profile and terrain reflectivity. In addition, atmospheric pressure, temperature and humidity data are recorded as functions of aircraft altitude, so that atmospheric refractivity gradients can be calculated, either by an on-board computer or later, and this factor taken into account during path design or performance simulation.
Inventors
- 👤 Ethelbert P. Elmore, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 02:46
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
337 words
An airborne geophysical measurement and recording system comprising: radar means for producing a focused radar signal, directing said signal to a terrain area below said aircraft and successively receiving a return signal from said terrain area, a linear range circuit connected to the output of said radar means for successively producing radar range signals from said return signal indicating the highest obstruction in said terrain area, an amplitude circuit connected to the output of said radar means for producing an echo magnitude signal which varies as a function of the maximum echo magnitude of said return signal, temperature means for detecting the atmospheric temperature and producing a temperature signal which varies as a function thereof, humidity means for detecting atmospheric humidity and producing a humidity signal which varies as a function thereof, aircraft height means for detecting aircraft altitude and producing an altitude signal, profile means for producing a profile signal which varies as a function of the difference between said range signal and said altitude signal, reflectivity means for producing a reflectivity signal which varies as a function of said echo magnitude signal, pressure means for detecting absolute atmospheric pressure and producing a pressure signal, means for recording said temperature signal, said humidity signal, said pressure signal, said altitude signal, said profile signal and said reflectivity signal, and means connected to said pressure means, and wet temperature means for producing from a plurality of data points taken at different altitudes a refractivity gradient dN/dh according to the relation N = 77.6 P/T + 3.73 × 10.sup.5 e/T.sup.2 where N is the radio refractivity in parts per million exceeding unity, h is the altitude at which the data points are taken, P is a data point representing the atmospheric pressure in millibars, T is a data point representing the temperature in degrees Kelvin, e is a data point representing the partial pressure of water vapor in millibars, and dN/dh is the refractivity gradient per kilometer of height in the lower air layer traversed by the microwave beam.
Claim 2
Dependent Claim
337 words
An airborne geophysical measurement and recording system comprising: radar means for producing a focused radar signal, directing said signal to a terrain area below said aircraft and successively receiving a return signal from said terrain area, a linear range circuit connected to the output of said radar means for successively producing radar range signals from said return signal indicating the highest obstruction in said terrain area, an amplitude circuit connected to the output of said radar means for producing an echo magnitude signal which varies as a function of the maximum echo magnitude of said return signal, temperature means for detecting the atmospheric temperature and producing a temperature signal which varies as a function thereof, humidity means for detecting atmospheric humidity and producing a humidity signal which varies as a function thereof, aircraft height means for detecting aircraft altitude and producing an altitude signal, profile means for producing a profile signal which varies as a function of the difference between said range signal and said altitude signal, reflectivity means for producing a reflectivity signal which varies as a function of said echo magnitude signal, pressure means for detecting absolute atmospheric pressure and producing a pressure signal, means for recording said temperature signal, said humidity signal, said pressure signal, said altitude signal, said profile signal and said reflectivity signal, and means connected to said pressure means, and wet temperature means for producing from a plurality of data points taken at different altitudes a refractivity gradient dN/dh according to the relation N = 77.6 P/T + 3.73 × 10.sup.5 e/T.sup.2 where N is the radio refractivity in parts per million exceeding unity, h is the altitude at which the data points are taken, P is a data point representing the atmospheric pressure in millibars, T is a data point representing the temperature in degrees Kelvin, e is a data point representing the partial pressure of water vapor in millibars, and dN/dh is the refractivity gradient per kilometer of height in the lower air layer traversed by the microwave beam.
Claim 3
Dependent Claim
15 words
A system as in claim 1 wherein said recording means includes a strip chart recorder.
Claim 4
Dependent Claim
26 words
A system as in claim 2 wherein said temperature means includes a dry bulb temperature detector and said humidity means includes a wet bulb temperature detector.
Claim 5
Dependent Claim
37 words
A system as in claim 1 wherein said recording means includes means for recording said temperature signal, said humidity signal, said pressure signal, said aircraft height signal, said profile signal and said reflectivity signal on magnetic tape.
Claim 6
Dependent Claim
19 words
A system as in claim 1 wherein said radar means includes a parabolic antenna directed vertically below the aircraft.
Claim 7
Dependent Claim
67 words
A system as in claim 1, wherein said reflectivity means includes a logarithmic amplifier connected to the output of said range circuit and a differential amplifier connected to the output to said logarithmic amplifier and to the output of said echo amplitude circuit for producing said reflectivity signal which varies as a function of the difference between said amplitude signal and the output of said logarithmic amplifier.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-09-19 | 1981-03-21 | 1981-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-19 | 1985-03-21 | 1985-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-19 | 1989-03-21 | 1989-09-20 | $7700.00 | Window Closed / Lapsed |