Sandia Research Corporation

Steven Michael Shope

Vigneswaran Rajagopalan

Paul Raymond Jorgenson

A method for subsurface radio communication includes transmitting voice data through a subsurface environment, by a transmitter of a radio transceiver. The voice data is received through the subsurface environment, by a receiver of the radio transceiver. A transceiver frequency of the radio transceiver is changed to an optimal transceiver frequency in response to a change to the subsurface environment. The transceiver frequency is one of a transmit frequency of the transmitter and a receive frequency of the receiver. A first impedance of a subwavelength antenna is matched to a second impedance of the transceiver in response to a difference between the first impedance and the second impedance exceeding an impedance mismatch value. The subwavelength antenna has a radiating length less than a transceiver wavelength of the radio transceiver operating in free-space at a maximum of the transceiver frequency.

Subsurface radio

A radar system () includes a transmitter (), a receiver (), and a software defined radio (SDR) peripheral (). Methodology () for investigating a target zone () utilizing the system () entails generating () a direct sequence spread spectrum (DSSS) code () having a code length () corresponding to a time duration of radio wave travel between the transmitter (), the target zone (), and the receiver () at a carrier frequency (). A beacon signal (), modulated () by the DSSS code (), is transmitted () from the transmitter () toward the target zone () and a return signal () is received () at the receiver (). The return signal () is compared () to a replica signal () characterized by the DSSS code (), and presence of an object () in the target zone () is ascertained () when the return signal () matches the replica signal ().

Surface penetrating radar system and target zone investigation methodology

A method of wireless communication in a lossy environment entails generating a direct sequence spread spectrum (DSSS) code string that includes a pseudo-noise (PN) sequence followed by instances of shifted PN sequences, where the shifted PN sequences are produced in response to the content of the message. The PN sequence includes a plurality of chips arranged in a first order, and each of the shifted PN sequences includes the plurality of chips arranged in another order. A beacon signal modulated by the DSSS code string is transmitted from a transceiver and received at a receiver within the communication system. Correlation peaks are formed at the receiver, where each correlation peak is associated with one of the PN sequences or one of the shifted PN sequences. Shift values are determined from the correlation peaks and the shift values are decoded to produce the message at the receiver.

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Mesa, AZ, United States of America

Steven Michael Shope