Patent•
Geophysical surveying system employing electromagnetic impulses
03 Jan 1972-
TL;DR: In this article, a geophysical survey system is disclosed for determining the character of the subterrain by analysis of reflections from electromagnetic pulses radiated into the ground, which is capable of generating a profile chart indicating the magnitudes of the reflected signals and the depths at which the reflections occurred.
Abstract: A geophysical survey system is disclosed for determining the character of the subterrain by analysis of reflections from electromagnetic pulses radiated into the ground. The system repetitively radiates into the ground a short duration electromagnetic pulse having a rise time in the order of 1 nanosecond. The antenna which radiates the pulse into the ground is employed to receive the reflections of the pulse. The received signals are coupled through a transmit-receive network to a receiver which permits the input signal waveform to be reconstructed from a sequence of samples taken by the receiver. The system is capable of generating a profile chart indicating the magnitudes of the reflected signals and the depths at which the reflections occurred.
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Patent•
30 Apr 2004
TL;DR: In this article, a time domain communications system is proposed where a broadband of time-spaced signals, essentially monocycle-like signals, are derived from applying stepped-in-amplitude signals to a broadband antenna, in this case, a reverse bicone antenna.
Abstract: A time domain communications system wherein a broadband of time-spaced signals, essentially monocycle-like signals, are derived from applying stepped-in-amplitude signals to a broadband antenna, in this case, a reverse bicone antenna. When received, the thus transmitted signals are multiplied by a D.C. replica of each transmitted signal, and thereafter, they are, successively, short time and long time integrated to achieve detection.
431 citations
Patent•
03 Dec 1984TL;DR: In this paper, an intelligence signal modulates the spacing of relatively narrow pulses of a fixed rate pulse train, and these pulses key on a transmitter which employs a pair of series connected avalanche mode operated transistors.
Abstract: A communications system wherein an intelligence signal modulates the spacing of relatively narrow pulses of a fixed rate pulse train, and these pulses key on a transmitter which employs a pair of series connected avalanche mode operated transistors. These are repetitively powered via a charged coaxial delay line, and the output, appearing across a resistive load, is fed directly, or through a shaping filter, to a discone transmitting antenna. At a receiving location, the received signal is amplified by a wide band amplifier and fed through a reverse contoured filter (of the transmitting filter, if one is employed). The signal is detected via synchronous detection which locks onto the received pulse train, after which the modulation evidence by the pulse train is recovered by a low pass filter.
232 citations
Patent•
30 Sep 2002TL;DR: In this article, the authors proposed an ultra wide bandwidth, high speed, spread spectrum communications system using short wavelets of electromagnetic energy to transmit information through objects such as walls or earth.
Abstract: An ultra wide bandwidth, high speed, spread spectrum communications system uses short wavelets of electromagnetic energy to transmit information through objects such as walls or earth. The communication system uses baseband codes formed from time shifted and inverted wavelets to encode data on a RF signal. Typical wavelet pulse durations are on the order of 100 to 1000 picoseconds with a bandwidth of approximately 8 GHz to 1 GHz, respectively. The combination of short duration wavelets and encoding techniques are used to spread the signal energy over an ultra wide frequency band such that the energy is not concentrated in any particular narrow band (e.g. VHF: 30-300 MHz or UHF: 300-1000 MHz) and is not detected by conventional narrow band receivers so it does not interfere with those communication systems. The use of pulse codes composed of time shifted and inverted wavelets gives the system according to the present invention has a spatial resolution on the order of 1 foot which is sufficient to minimize the negative effects of multipath interference and permit time domain rake processing.
220 citations
Patent•
19 May 2009
TL;DR: The functionalized proppants can be detected by a variety of methods utilizing, for example, an airborne magnetometer survey, ground penetrating radar, a high resolution accelerometer, a geophone, nuclear magnetic resonance, ultra-sound, impedance measurements, piezoelectric activity, radioactivity, and the like as discussed by the authors.
Abstract: Proppants having added functional properties are provided, as are methods that use the proppants to track and trace the characteristics of a fracture in a geologic formation. Information obtained by the methods can be used to design a fracturing job, to increase conductivity in the fracture, and to enhance oil and gas recovery from the geologic formation. The functionalized proppants can be detected by a variety of methods utilizing, for example, an airborne magnetometer survey, ground penetrating radar, a high resolution accelerometer, a geophone, nuclear magnetic resonance, ultra-sound, impedance measurements, piezoelectric activity, radioactivity, and the like. Methods of mapping a subterranean formation are also provided and use the functionalized proppants to detect characteristics of the formation.
218 citations
TL;DR: In this paper, ground penetrating radar data is not always easy to acquire, and sometimes the acquisition may be constrained by equipment availability, weather, legal or logistical constraints, safety or access considerations.
164 citations
References
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Patent•
30 Apr 1963
49 citations
Patent•
01 Aug 1933
TL;DR: In this article, an improvement in electrical subsurface prospecting to determine the character and location of geological formations by transmitting to the earth electrical impulses and detecting the reflected or refracted portions of such impulses was proposed.
Abstract: The invention relates to an improvement in electrical subsurface prospecting to determine the character and location of geological formations by transmitting to the earth electrical impulses and detecting the reflected or refracted portions of such impulses. The invention is predicated upon...
49 citations
Patent•
02 Apr 1969TL;DR: In this article, a method of determining leakage from a buried pipeline using a closed-loop radar system having time-sharing transmission line buried adjacent to the pipeline to be monitored is presented.
Abstract: A method of determining leakage from a buried pipeline using a closed-loop radar system having time-sharing transmission line buried adjacent to the pipeline to be monitored.
40 citations