Radio frequency seismic gathering system employing an airborne blimp
First Claim
1. In combination with a seismic gathering system employinga plurality of field unit seismic detectors, each of the detectors including a receiver and a controllable rf transmitter, a predetermined received signal activating the transmitter at each of the detectors, anda central data gathering station for transmitting predetermined signals to selectively controllably activate the transmitters at the field detectors and for receiving and recording the transmissions from the field detectors,the improvement in a central gathering station comprisingground station apparatus includingrecording means for recording seismic data,a power supply for supplying operating power to said recording means and including a variable dc voltage output,switching means connected to the variable dc voltage output from said power supply and to said recording means,an rf coaxial cable connected to said switching means, andblimp station apparatus includinga tethered aerodynamically stabilized blimp,rf radio receiver means carried by said blimp and includingdecoupling means connected to said rf coaxial cable for separating rf signals from said variable dc voltage,a preamplifier having a gain control connected to said decoupled variable dc output and having an rf output connected to said rf coaxial cable, andantenna means for receiving field detector transmissions, said antenna means being coupled to said preamplifier for producing rf seismic data transmissions on said rf coaxial cable to said recording means.
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Accused Products
Abstract
The central station of a radio-connected seismic surveying system uses a tethered blimp carrying an antenna and an electronics package including a dc voltage/rf decoupler, a variable dc controlled preamplifier, a P-I-N diode switch for changing the antenna from receive to transmit operation, a transmitter and modulator and a battery. An rf coaxial cable to ground provides means for controlling the preamplifier gain and for switching the central station to the transmit mode by using appropriate dc signals. In the receive mode, the cable carries detected field unit seismic signals, which are detected by the blimp-carried antenna and preamplified by the blimp preamplifier, to the ground for suitable recording and further processing in the ground portion of the central station. An audio channel can also be modulated onto the transmit carrier of approximately 70 MHz to provide voice communications via the blimp electronics, if desired. Both the ground portion and the blimp portion of the central station are packaged for helicopter transporting.
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Citations
10 Claims
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1. In combination with a seismic gathering system employing
a plurality of field unit seismic detectors, each of the detectors including a receiver and a controllable rf transmitter, a predetermined received signal activating the transmitter at each of the detectors, and a central data gathering station for transmitting predetermined signals to selectively controllably activate the transmitters at the field detectors and for receiving and recording the transmissions from the field detectors, the improvement in a central gathering station comprising ground station apparatus including recording means for recording seismic data, a power supply for supplying operating power to said recording means and including a variable dc voltage output, switching means connected to the variable dc voltage output from said power supply and to said recording means, an rf coaxial cable connected to said switching means, and blimp station apparatus including a tethered aerodynamically stabilized blimp, rf radio receiver means carried by said blimp and including decoupling means connected to said rf coaxial cable for separating rf signals from said variable dc voltage, a preamplifier having a gain control connected to said decoupled variable dc output and having an rf output connected to said rf coaxial cable, and antenna means for receiving field detector transmissions, said antenna means being coupled to said preamplifier for producing rf seismic data transmissions on said rf coaxial cable to said recording means.
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10. In combination with a seismic gathering system employing
a plurality of field unit seismic detectors, each of the detectors including a receiver and a controllable rf transmitter, a predetermined received signal activating the transmitter at each of the detectors, and a central data gathering station for transmitting predetermined signals to selectively controllably activate the transmitter at the field detectors and for receiving and recording the transmissions from the field detectors, the improvement in a central gathering station comprising ground station apparatus including recording means for recording seismic data, a power supply for supplying operating power to said recording means and including a variable dc voltage output, switching means connected to the variable dc voltage output from said power supply and to said recording means, blimp station apparatus including a tethered aerodynamically stabilized blimp having a reflective surface. rf radio receiver means including decoupling means connected to the output of said switching means for separating rf signals from said variable dc voltage, a preamplifier having a gain control connected to said decoupled variable dc output and having an rf output connected as an input to said switching means, and antenna means for receiving field detectors transmissions following reflection from the reflective surface of said blimp station apparatus, said antenna means being coupled to said preamplifier for producing rf seismic data transmissions to said recording means.
Specification