Embodiments are directed to methods involving generating a baseband signal, up-converting the baseband signal to a radar signal frequency, filtering a lower sideband of the up-converted signal, and transmitting the filtered up-converted signal. Methods also involve receiving a return signal, down-converting the return signal using a signal having a frequency offset from the up-converted signal, filtering the upper sideband of the down-converted return signal, and producing a baseband return signal.
According to other embodiments, methods involve generating a baseband signal, mixing the baseband signal with a transmit oscillator signal to produce a mixed transmit signal comprising a lower sideband and an upper sideband, filtering the lower sideband of the mixed transmit signal, and transmitting the filtered mixed transmit signal. Methods also involve receiving a return signal resulting from transmitting the filtered mixed transmit signal and generating a receive oscillator signal having a frequency offset from that of the transmit signal by a predetermined frequency. Methods further involve mixing the return signal with the receive oscillator signal to produce a mixed receive signal comprising a lower sideband and an upper sideband, and filtering the upper sideband of the mixed receive signal to produce a baseband return signal.
In accordance with various embodiments, a radar apparatus includes an antenna arrangement, a signal generator configured to generate a baseband signal, and a transmit section, coupled to the signal generator and the antenna arrangement, comprising a transmit oscillator operating at a predetermined frequency. The transmit section is configured to generate a transmit signal comprising a mix of the baseband signal and a signal at the predetermined frequency, and to filter a lower sideband of the mixed transmit signal. A receive section is coupled to the antenna arrangement and a sideband filter. The receive section comprises a receive oscillator configured to operate at a frequency offset from that of the transmit oscillator by a frequency greater than or equal to a width of the sideband filter. The receive section is configured to mix a return signal received by the antenna arrangement and a signal produced by the receive oscillator at the offset frequency to produce a mixed receive signal comprising a lower sideband and an upper sideband, and to filter the upper sideband of the mixed receive signal to produce a baseband return signal.
These and other features can be understood in view of the following detailed discussion and the accompanying drawings.
In the following description of the illustrated embodiments, references are made to the accompanying drawings forming a part hereof, and in which are shown by way of illustration, various embodiments by which the invention may be practiced. It is to be understood that other embodiments may be utilized, and structural and functional changes may be made without departing from the scope of the present invention.
Systems, devices or methods according to the present invention may include one or more of the features, structures, methods, or combinations thereof described herein. For example, a device or system may be implemented to include one or more of the useful features and/or processes described below. It is intended that such a device or system need not include all of the features described herein, but may be implemented to include selected features that provide for useful structures, systems, and/or functionality.
Embodiments are directed to an offset frequency homodyne radar and methods of using same. Embodiments are directed to an offset frequency homodyne ground penetrating radar and methods of using same. Various embodiments are directed to an offset frequency homodyne arbitrary waveform radar that can be used in subsurface radar applications. A radar architecture according to various embodiments is that of an arbitrary waveform, frequency domain radar, which provides for increased flexibility in terms of the types of waveforms that can be transmitted. Wideband arbitrary waveform operation according to some embodiments allows tailoring of the transmit waveform to a specific application and/or target, or the operating environment (e.g., noise location in frequency). In addition to an SFCW signal, for example, broader instantaneous frequency signals can be transmitted that may result in higher amplitude responses, collected in shorter times.
Embodiments of the disclosure directed to a small size, low power radar that can be installed on a drill head (e.g., for horizontal directional drilling (HDD) or oil and gas drilling) for use in obstacle detection or general mapping. Embodiments of an offset frequency radar for use on a drill provides for mapping and detection of objects (e.g., obstacles, cavities, geologic contacts, mineralized zones, etc.) during drilling, without the need of a pre-existing bore hole. Embodiments of an offset frequency homodyne radar can be applied to through-the-wall monitoring, among others.
Some embodiments are directed to a wideband arbitrary waveform low power radar system for near range (e.g., <100 m) sensing that utilizes an offset radio frequency architecture to optimize signal quality while at the same time minimizing the required components to implement the system. Embodiments are directed to an offset frequency homodyne radar architecture that, through careful selection of the transmit and local oscillator frequency, utilizes a digitization anti-aliasing filter to attenuate an unwanted transmit sidelobe. The architecture also reduces all transmit harmonics prior to digitization.
A radar architecture according to various embodiments provides for increased hardware simplicity over conventional architectures that results in improved sideband rejection and wide dynamic range, without additional mixing stages required with standard heterodyne radar structures. Embodiments are directed to an improved radar architecture with enhanced sideband suppression using an offset homodyne architecture, which lends itself to the construction of an arbitrary waveform radar with very good noise and sideband suppression, while providing a more inexpensive approach to improve signal quality. An offset frequency homodyne architecture in accordance with various embodiments utilizes an anti-aliasing filter to advantageously reduce sidelobes and transmit harmonics prior to digitization.
The motivation for a second IF frequency in super-heterodyne architectures is to ensure a clean transmit spectrum and as a result a clean receive spectrum; with no harmonics or sub-harmonics that interact with the target and are then mixed down into the same band as the carrier and waveform. However, based on simulations, it seems extremely difficult to space out the radar modulation frequencies such that this occurs. It would be more promising if the resultant baseband spectrum was clean, i.e., no overlapping of different mixing products at baseband. Most conventional wideband arbitrary waveform systems use one or more intermediate frequency stages to sufficiently attenuate the sidelobes to a level that does not affect the performance of the radar system. This both introduces additional components and hence size and power requirements; but also addition of non-linear components that adds noise and harmonics to the system, which makes designing wideband arbitrary waveform systems more complex.
Embodiments of an offset frequency radar system require fewer components than conventional wideband arbitrary waveform radar systems, for the same performance and functionality. In doing so, an offset frequency radar system according to various embodiments allows one to target applications requiring radar sensing but with limited space to house the electronics. For example, embodiments of the disclosure are directed to solving the problem of near range sensors for obstacle avoidance applications, which have limited space requirements for sensor electronics. An offset frequency radar architecture can also be applied to other ground penetrating radar problems ranging from utility location to archeology according to various embodiments. An additional problem that can be addressed is inspection of the vicinity of non-metallic pipes, such as from a location in the pipe (e.g., a pipe pig). By way of further example, an offset frequency radar can be used in short range applications of through-the-wall imaging and rescue operations.
Moreover, embodiments of the disclosure avoid the complexity of a second IF stage required by a super-heterodyne design and splits the local (LO) oscillators into a transmit and receive oscillator that are offset by a frequency greater than or equal to the width of a sideband (e.g., Nyquist) filter of the receiver. This solves the issue of phase jitter by always sampling a reference channel along with the device under test (DUT). In addition, the transmit modulator (e.g., single sideband or SSB) according to various embodiments improves the measurement speed by supporting a larger instantaneous bandwidth according to various embodiments.
Turning now to
Referring to
A receive section of the radar system illustrated in
Mixing the return signal and the receive oscillator signal at the offset frequency effectively flips the return signal (e.g., a return of the upper sideband of the mixed transmit signal) into the lower sideband of the mixed return signal. The sideband filter 324, which is preferrably a Nyquist filter, is configured to attenuate the unwanted upper sideband of the mixed return signal. The filtered mixed return signal is then digitized and processed to construct a time-domain signal or pulse (e.g., a time domain trace). For example, the filtered mixed return signal is digitized and processed by an inverse Fourier transform unit 330. The time-domain signal output from the inverse Fourier transform unit 330 can be communicated to a human-machine interface (HMI) 332 for displaying the processed return signal.
In some embodiments, the radar system shown in
The receive reference branch 530 includes a receive quadrature mixer 532 and a lowpass filter 534, which is preferably configured as a Nyquist filter. A receive oscillator 520 is coupled to the receive mixer 532, and is offset to the frequency of the transmit oscillator 530 by a predetermined amount, such as 100 MHz in this illustrative embodiment. The receive quadrature mixer 532 and the lowpass filter 534 generally correspond to the mixer 322 and filter 324 described previously with regard to
As the RF chain is fed with a sinusoidal waveform produced by a signal generator and communicated to the transmit mixer 503, the resulting signal at each of test points A-E was measured on a spectrum analyser and compared to simulations discussed previously. In
The dual receive channels of the receive section 551, with one reference channel 530 and one DUT channel 540, supports removal of phase errors. Internal calibration of the radar can be implemented in this design. For example, both S11 (TX) and S21 measurements can be provided, with a more complete on-the-fly tuning of the radar to its surroundings. This can increase the SNR through optimum waveform design.
The offset frequency homodyne radar architecture lends itself to function as an arbitrary waveform radar according to various embodiments, as was discussed previously. First, an offset frequency homodyne radar can be operated as a SFCW system, where one frequency packet is transmitted for each setting of the transmit local oscillator. The next step in this example is to transmit several frequencies (offset from each other by a constant interval) in each transmit LO setting. In this case, an equivalent SFCW waveform is transmitted, but with several frequencies sent per transmit LO setting. Thus, there are fewer transmit LO settings per radar trace and measurement speed is increased by a factor equal to the number of frequencies transmitted per step. This operation is possible because the passband of the Nyquist filter is 20-100 MHz rather than a very narrow filter according to various embodiments. Other waveforms can as easily be transmitted by mixing with the transmit LO, such as FMCW, stepped FMCW, noise, and coded signals. For each waveform transmitted, the DAC of the signal generator that controls waveform generation is only coded and set once. The range of frequencies to be transmitted is varied by changing the transmit LO frequency in a limited number of steps. Thus, an arbitrary waveform can be built-up piecewise, resulting in faster radar trace collection.
The following representative example illustrates aspects of an offset frequency homodyne radar detection implementation in accordance with various embodiments. In the following example, reference is made to the plot of
In this representative example, assume that a single 30 MHz signal is mixed with the transmit LO at 800 MHz. After the IF filter, a frequency of 830 MHz goes to both the transmit antenna and the receive section, which can include a calibration branch. The 830 MHz is then modulated with the receiver LO at 900 MHz, giving 1730 MHz and 70 MHz. The upper side band is easily filtered, and the down-converted lower side band of 70 MHz passes on to be digitized and processed. An interesting aspect of this design is that the upper sideband that was transmitted has now been flipped into the lower sideband and filtered by the 100 MHz Nyquist filter, as is shown in
To verify the efficacy of an offset frequency homodyne radar detection implementation in accordance with various embodiments, the RF system was simulated in Genesys using the Spectrasys tool. The results for the frequency domain simulation were plotted. A plot of power as a function of frequency for all the harmonic and intermodulation products for the transmit waveform showed many harmonics and intermodulation products. However, since the transmit and receiver LO are offset, most of these signals do not mix down to the baseband of the radar. The only unwanted mixing products were more than 80 dB below the desired signal. The results for a transmit waveform consisting of 5 CW signals spaced 8 MHz apart were also plotted. One plot showed that the 5 CW signals are cleanly mixed down to below 100 MHz while the various intermodulation products are mixed to frequencies greater than 100 MHz. After filtering with the Nyquist low pass filter, the unwanted signals were completely removed, as was shown in another plot.
Embodiments of an offset frequency homodyne radar has significant potential benefits. First, an offset frequency homodyne radar takes advantage of advances that have been made in hardware components. These include higher density FPGA chips, faster ADC chips, and better communications devices. By changing the design to have an intermediate frequency (IF) of 20-100 MHz, for example, a broader frequency span can be used in less time. Thus, measurement speed is increased.
The homodyne drill head radar embodiment shown in
The RF components in the radar system have also benefited from technological advances in the telecommunication industry. High speed ADCs and DACs with high linearity (16 bits) can be used to generate and capture the radar waveforms. Integrated, small wireless chips can be used to perform the modulation, filtering, calibration and antenna interfacing. Most devices support two signal paths, thus reducing the number of devices needed to implement the system and hence the size of the system. Synthesizers now include VCOs and make the design and implementation of low noise RF sources straightforward. In addition there are many wide band quadrature modulators and dual wideband mixers with integrated LO drive amplifiers available from numerous vendors.
The Borph interface of the Rhino module 1312 to the FPGA is performed on the CPU, such as CPU 1422 shown in
With reference to
Horizontal directional drilling provides numerous advantages over the historical trench based techniques for subsurface utility installation. However, HDD does suffer from the constant threat of striking unknown, unmapped, or mis-located utilities and other obstacles. Striking these obstacles can cost the operator revenues, for repairs, or in more serious cases result in loss of equipment, injury, or death. Thus, there is a need for sensors that can be mounted on the drill head that detect obstacles far enough in advance to allow the drill operator to detect and/or map them. An offset frequency homodyne drill head radar incorporated into an HDD machine provides for enhanced detecting and/or mapping of obstacles to allow their avoidance, which is of great importance, especially when damaging one of these features could result in disruption of utility service or possible contaminant release.
A typical boring operation can take place as follows. The rotation motor 1619 is initially positioned in an upper location 1619a and rotates the drill string 1622. While the boring tool 1624 is rotated through rotation of the drill string 1622, the rotation motor 1619 and drill string 1622 are pushed in a forward direction by the thrust/pullback pump 1617 toward a lower position into the ground, thus creating a borehole 1626. The rotation motor 1619 reaches a lower position 1619b when the drill string 1622 has been pushed into the borehole 1626 by the length of one drill string member 1623. A new drill string member 1623 is then added to the drill string 1622 either manually or automatically, and the rotation motor 1619 is released and pulled back to the upper location 1619a. The rotation motor 1619 is used to thread the new drill string member 1623 to the drill string 1622, and the rotation/push process is repeated so as to force the newly lengthened drill string 1622 further into the ground, thereby extending the borehole 1626.
Commonly, water or other fluid is pumped through the drill string 1622 (referred to herein as mud) by use of a mud pump. If an air hammer is used, an air compressor is used to force air/foam through the drill string 1622. The mud or air/foam flows back up through the borehole 1626 to remove cuttings, dirt, and other debris and improve boring effectiveness and/or efficiency.
A directional steering capability is typically provided for controlling the direction of the boring tool 1624, such that a desired direction can be imparted to the resulting borehole 1626. By these actions, and various combinations of these basic actions, a boring procedure can advance a boring tool 1624 through soil, including advancing the boring tool 1624 through a turn. Because HDD typically does not bore a hole very far from the surface of the ground, many belowground obstacles (e.g., sewers, electrical lines, building foundations, etc.) must be maneuvered around. As such, many boring tools are configured to allow the bore path to turn (e.g., left, right, higher, lower) to curve the bore path around underground obstacles.
In accordance with some embodiments, the system also includes an encoder 1619c to monitor of the position of the boring tool 1624. As the drill head 1624 is pushed into the ground, a cable plays out and advances the encoder 1619c, providing the system software with a measure of the drill head location and triggering radar electronics at discrete distance intervals.
The discussion and illustrations provided herein are presented in an exemplary format, wherein selected embodiments are described and illustrated to present the various aspects of the present invention. Systems, devices, or methods according to the present invention may include one or more of the features, structures, methods, or combinations thereof described herein. For example, a device or system may be implemented to include one or more of the advantageous features and/or processes described below. A device or system according to the present invention may be implemented to include multiple features and/or aspects illustrated and/or discussed in separate examples and/or illustrations. It is intended that such a device or system need not include all of the features described herein, but may be implemented to include selected features that provide for useful structures, systems, and/or functionality.
Although only examples of certain functions may be described as being performed by circuitry for the sake of brevity, any of the functions, methods, and techniques can be performed using circuitry and methods described herein, as would be understood by one of ordinary skill in the art.
It is to be understood that even though numerous characteristics of various embodiments have been set forth in the foregoing description, together with details of the structure and function of various embodiments, this detailed description is illustrative only, and changes may be made in detail, especially in matters of structure and arrangements of parts illustrated by the various embodiments to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
This application claims the benefit of Provisional Patent Application Ser. No. 61/609,715 filed on Mar. 12, 2012, to which priority is claimed pursuant to 35 U.S.C. §119(e) and which is hereby incorporated herein by reference in its entirety.
Number | Name | Date | Kind |
---|---|---|---|
3288242 | Loeb | Nov 1966 | A |
3852743 | Gupta | Dec 1974 | A |
4297699 | Fowler et al. | Oct 1981 | A |
4430653 | Coon et al. | Feb 1984 | A |
4492865 | Murphy et al. | Jan 1985 | A |
4504833 | Fowler | Mar 1985 | A |
4676695 | Duthweiler | Jun 1987 | A |
4686475 | Kober et al. | Aug 1987 | A |
4698634 | Alongi et al. | Oct 1987 | A |
4709237 | Poullain et al. | Nov 1987 | A |
4710708 | Rorden et al. | Dec 1987 | A |
4728897 | Gunton | Mar 1988 | A |
4806869 | Chau et al. | Feb 1989 | A |
4814768 | Chang | Mar 1989 | A |
4843597 | Gjessing et al. | Jun 1989 | A |
4873513 | Soults et al. | Oct 1989 | A |
4896116 | Nagashima et al. | Jan 1990 | A |
4899322 | Crutcher et al. | Feb 1990 | A |
4905008 | Kawano et al. | Feb 1990 | A |
4912643 | Beirne | Mar 1990 | A |
5033031 | Bohman | Jul 1991 | A |
5065098 | Salsman et al. | Nov 1991 | A |
5092657 | Bryan, Jr. | Mar 1992 | A |
5103920 | Patton | Apr 1992 | A |
5113192 | Thomas | May 1992 | A |
5264795 | Rider | Nov 1993 | A |
5274557 | Moriya et al. | Dec 1993 | A |
5321613 | Porter et al. | Jun 1994 | A |
5325095 | Vadnais et al. | Jun 1994 | A |
5337002 | Mercer | Aug 1994 | A |
5339080 | Steinway et al. | Aug 1994 | A |
5341886 | Patton | Aug 1994 | A |
5357253 | Van Etten | Oct 1994 | A |
5365442 | Schmidt | Nov 1994 | A |
5370478 | Bartlett et al. | Dec 1994 | A |
5375663 | Teach | Dec 1994 | A |
5384715 | Lytton | Jan 1995 | A |
5410252 | Potter et al. | Apr 1995 | A |
5412623 | Asada et al. | May 1995 | A |
5446981 | Kamada et al. | Sep 1995 | A |
5469155 | Archambeault et al. | Nov 1995 | A |
5471771 | Gilbert | Dec 1995 | A |
5499029 | Bashforth et al. | Mar 1996 | A |
5509220 | Cooper | Apr 1996 | A |
5512834 | McEwan | Apr 1996 | A |
5528518 | Bradshaw et al. | Jun 1996 | A |
5544052 | Fujita et al. | Aug 1996 | A |
5546572 | Seto et al. | Aug 1996 | A |
5553407 | Stump | Sep 1996 | A |
5585726 | Chau | Dec 1996 | A |
5607205 | Burdick et al. | Mar 1997 | A |
5614670 | Nazarian et al. | Mar 1997 | A |
5631970 | Hsu | May 1997 | A |
5633589 | Mercer | May 1997 | A |
5644237 | Eslambolchi et al. | Jul 1997 | A |
5659985 | Stump | Aug 1997 | A |
5673050 | Moussally et al. | Sep 1997 | A |
5682136 | Del Signore | Oct 1997 | A |
5698981 | Mercer | Dec 1997 | A |
5704142 | Stump | Jan 1998 | A |
5711381 | Archambeault et al. | Jan 1998 | A |
5720354 | Stump et al. | Feb 1998 | A |
5746278 | Bischel | May 1998 | A |
5757320 | McEwan | May 1998 | A |
5764062 | Mercer | Jun 1998 | A |
5767678 | Mercer | Jun 1998 | A |
5769503 | Stolarczyk et al. | Jun 1998 | A |
5774091 | McEwan | Jun 1998 | A |
5786537 | Anstey | Jul 1998 | A |
5805110 | McEwan | Sep 1998 | A |
5819859 | Stump et al. | Oct 1998 | A |
5825660 | Cagan et al. | Oct 1998 | A |
5844564 | Bennis et al. | Dec 1998 | A |
5867117 | Gogineni et al. | Feb 1999 | A |
5872537 | Siweris | Feb 1999 | A |
5904210 | Stump et al. | May 1999 | A |
5933014 | Hartrumpf et al. | Aug 1999 | A |
6014343 | Graf et al. | Jan 2000 | A |
6035951 | Mercer et al. | Mar 2000 | A |
6072427 | McEwan | Jun 2000 | A |
6078869 | Gunasekera | Jun 2000 | A |
6088294 | Leggett, III et al. | Jul 2000 | A |
6106561 | Farmer | Aug 2000 | A |
6119804 | Owen | Sep 2000 | A |
6150976 | Cooley | Nov 2000 | A |
6151555 | Van Bemmel et al. | Nov 2000 | A |
6195922 | Stump | Mar 2001 | B1 |
6216540 | Nelson | Apr 2001 | B1 |
6225941 | Gogineni et al. | May 2001 | B1 |
6252538 | Chignell | Jun 2001 | B1 |
6302221 | Hamman et al. | Oct 2001 | B1 |
6307573 | Barros | Oct 2001 | B1 |
6308787 | Alft | Oct 2001 | B1 |
6313755 | Hetmaniak et al. | Nov 2001 | B1 |
6315062 | Alft et al. | Nov 2001 | B1 |
6327533 | Chou | Dec 2001 | B1 |
6363320 | Chou | Mar 2002 | B1 |
6373486 | Simpson | Apr 2002 | B1 |
6377201 | Chu | Apr 2002 | B1 |
6377210 | Moore | Apr 2002 | B1 |
6389360 | Alft et al. | May 2002 | B1 |
6414627 | McEwan | Jul 2002 | B1 |
6435286 | Stump et al. | Aug 2002 | B1 |
6437726 | Price | Aug 2002 | B1 |
6462696 | Gorman | Oct 2002 | B1 |
6477795 | Stump | Nov 2002 | B1 |
6484818 | Alft et al. | Nov 2002 | B2 |
6501413 | Annan et al. | Dec 2002 | B2 |
6522290 | Mattox | Feb 2003 | B2 |
6532190 | Bachrach | Mar 2003 | B2 |
6617856 | Royle | Sep 2003 | B1 |
6664914 | Longstaff | Dec 2003 | B2 |
6667709 | Hansen et al. | Dec 2003 | B1 |
6700526 | Witten | Mar 2004 | B2 |
6701647 | Stump | Mar 2004 | B2 |
6719069 | Alft et al. | Apr 2004 | B2 |
6739165 | Strack | May 2004 | B1 |
6751553 | Young et al. | Jun 2004 | B2 |
6755263 | Alft et al. | Jun 2004 | B2 |
6766253 | Burns et al. | Jul 2004 | B2 |
6833795 | Johnson et al. | Dec 2004 | B1 |
6886644 | Stump et al. | May 2005 | B2 |
6915211 | Kram et al. | Jul 2005 | B2 |
6975942 | Young et al. | Dec 2005 | B2 |
6980482 | Faichney et al. | Dec 2005 | B2 |
7013991 | Wilson-Langman | Mar 2006 | B2 |
7034740 | Witten | Apr 2006 | B2 |
7065446 | Chou | Jun 2006 | B2 |
7072668 | Chou | Jul 2006 | B2 |
7085196 | Nemeth | Aug 2006 | B2 |
7113124 | Waite | Sep 2006 | B2 |
7123016 | Larsen | Oct 2006 | B2 |
7143844 | Alft et al. | Dec 2006 | B2 |
7182151 | Stump et al. | Feb 2007 | B2 |
7184611 | Miyagi et al. | Feb 2007 | B2 |
7202801 | Chou | Apr 2007 | B2 |
7218244 | Jin et al. | May 2007 | B2 |
7400976 | Young et al. | Jul 2008 | B2 |
7424133 | Schultz et al. | Sep 2008 | B2 |
7612704 | Ryerson et al. | Nov 2009 | B2 |
7676534 | Murakami et al. | Mar 2010 | B2 |
7773205 | Cooper | Aug 2010 | B2 |
7930103 | Young et al. | Apr 2011 | B2 |
8207887 | Goldman | Jun 2012 | B2 |
8280634 | Young et al. | Oct 2012 | B2 |
20020130806 | Taylor et al. | Sep 2002 | A1 |
20030012411 | Sjostrom et al. | Jan 2003 | A1 |
20030090406 | Longstaff | May 2003 | A1 |
20040168358 | Stump | Sep 2004 | A1 |
20080079723 | Hanson et al. | Apr 2008 | A1 |
20080088503 | Beasley | Apr 2008 | A1 |
20090251361 | Beasley | Oct 2009 | A1 |
20110202277 | Haddad | Aug 2011 | A1 |
Number | Date | Country |
---|---|---|
9108986 | Dec 1991 | DE |
9214241 | Jan 1993 | DE |
19509934 | Oct 1995 | DE |
19845330 | Apr 2000 | DE |
10018031 | Oct 2001 | DE |
0269283 | Jun 1988 | EP |
0289623 | Sep 1993 | EP |
2673002 | Aug 1992 | FR |
03187423 | Aug 1991 | JP |
6230141 | Aug 1994 | JP |
9002065 | Apr 1992 | NL |
Entry |
---|
“AD8349 Data Sheet Rev. B”, http://www.analog.com/static/imported-files/data—sheet/AD8349.pdf, Feb. 24, 2012. |
Aaltonen et al., “Geological Mapping Using GPR and Differential GPS Positioning: A Case Study”, Proceedings of the Ninth International Conference on GPR, Apr. 29-May 2, 2002, Santa Barbara, California, pp. 207-210. |
Akita et al., “Practical Usage and Future Prospects of a Mapping System Using a Pen-Based Computer”, Proceedings AM/FM International Annual Conference, Mar. 20, 1995, pp. 699-707. |
Alippi et al., “Hardware Requirements for Digital VLSI Implementation of Neural Networks”, IEEE International Joint Conference on Neural Networks, vol. 3, 1991, pp. 1873-1878 (Abstract only). |
AWPA—“Uniform Color Code”, Mar. 6, 2001—http://web.archive.org/web/20010306004125/http://www.callbeforeyoudig.org/color.htm. |
Baker et al., “Source-Dependent Frequency Content of Ultrashallow Seismic Reflection Data”, Bulletin of the Seismological Society of America, 90, 2, p. 494-499, Apr. 2000. |
Bakhtar et al., “Testing and UXO Detection Using US Air Force EarthRadar System,” Mar. 1996. |
Bernold et al., “A Multi-Sensory Approach to 3-D Mapping of Underground Utilities”, 19th Proceedings of International Symp. on Automation & Robotics in Construction, Sep. 23-25, 2002. |
Chuang et al., “A Highly Capable Arbitrary Waveform Generator for Next Generation Radar Systems”, Aerospace Conference, 2006 IEEE, 5 pages. |
“Ditch Witch Subsite Trac Management System Plus”, http://www.ditchwitch.com/produtct/productview/138 Accessed Aug. 13, 2002. |
Dobecki et al. “Geotechnical and Groundwater Geophysics.” Geophysics, vol. 50, No. 12, Dec. 1985, p. 2621-2636 (abstract only). |
“Drill Path,” Infrasoft, LLC., Computer Software for Solving Infrastructure Problems, 2916 West T.C. Jester, Houston, Texas 77018, 20 pages. |
Dussauge-Peisser et al., Investigation of a fractured limestone cliff (Chartreuse Massif, France) using seismic tomography and ground-penetrating radar Near Surface Geophysics, 1, 161-170, Aug. 2003. |
Farquharson et al., “A 50-800 MHz stepped frequency continuous wave ground penetrating radar”, Communications and Signal Processing, 1998. Comsig '98. Proceedings of the 1998 South African Symposium on Rondebosch, South Africa 7-8 Sep. 7-8, 1998. New York, NY, USA, IEEE, US, pp. 455-460. (abstract only). |
Fenning et al., Geophysical Methods for the Location of Underground Storage Tanks, Article (no copy available). |
Figdor et al. “Geophysical reconnaissance of covered waste disposal grounds.” OEIAZ Austrian Engineer and Architects' Magazine, vol. 134, No. 9, Austria, Sep. 1989. pp. 450-456 (no copy available). |
Frohlich et al., “Exploring geo-scientific data in virtual environments”, Proceedings of the Conference on Visualization 1999: Celebrating Ten Years, IEEE Visualization, IEEE Computer Society Press, Los Alamitos, CA, pp. 169-173, Oct. 1999. |
Guenther et al., Proceedings of the Fifth International Conference on Ground Penetrating Radar, The Geophysical Investigation of Drilling Obstacles for Microtunnelling Projects by Means of GPR, vol. 3 of 3, Jun. 1994, pp. 1151-1165. (Abstract only). |
Haizhong et al., Derivative Seismic Processing Method for GPR Data, 1997 IEEE, pp. 145-147. (Abstract only). |
Herman, “Robotic Subsurface Mapping Using Ground Penetrating Radar”, PhD thesis, Carnegie Mellon University, May 1997, 143 pages. |
Hodgson, “Computerized Well Planning for Directional Wells”, SPE, No. 12071, Oct. 8, 1983, pp. 1-6 (abstract only). |
Hussain et al., Application of Migration to Ground Probing Radars, 1988 IEEE, pp. 1208-1211. (Abstract only). |
Kathage, Proceedings of the Fourth International Conference on Ground Penetrating Radar, Geological Survey of Finland, A Challenge: GPR in Advance of Horizontal Drilling, Special Paper 16, Jun. 1992, pp. 119-124. (Abstract only). |
Lee, “A GNU Radio Based Software-Defined Radar”, http://etd.ohiolink.edu/send-pdf.cgi/PattonLee.pdf?wright1176142845, Apr. 9, 2007. |
Liu, “Using GPR and seismic reflection measurements to characterize buried objects: large-scale simulation.” IGARSS '97. 1997 in'tl Geoscience and Remote Sensing Symposium. pp. 1147-1149, vol. 3. |
Liu et al. “Identification of paleo-liquefaction and deformation features with GPR in the New Madrid seismic zone.” The 8th Int'l Conference of Ground Penetrating Radar. Goldcoast, May 23-26, 2000. vol. 4084, pp. 383-389 (abstract only). |
McFee et al., “Multisensor vehicle-mounted teleoperated mine detector with data fusion”, Proc. SPIE, vol. 3392, 1082, 1998, abstract only. |
Parker, “Buried Facility Locating with GPS Interface,” GBIS '99, Edmonton, Dec. 1999. |
Powers et al., “Integrated Use of Continuous Seismic-Reflection Profiling and Ground-Penetrating Radar Methods at John's Pond, Cape Cod, Massachusetts”, 12th Proceeding on Applications of Geophysics to Eng. & Environment, 1999 (abstract only). |
Reinhard et al., “An IQ-modulator based heterodyne 77-GHz FMCW radar”, Microwave Conference (GEMIC), 2011 German, IEEE, Mar. 14, 2011, pp. 1-4. (abstract only). |
Santos, “The Development and Field Application of a 3D Computer Graphics System for Displaying Wellbore Trajectories”, SPE, No. 29197, Nov. 10, 1994, pp. 371-382. |
Schwamborn et al. “Ground penetrating radar and shallow seismic-stratigraphic and permafrost investigations of Lake Nikolay, Delta Lena and Arctic Siberia.” The 8th Int'l Conference of Ground Penetrating Radar. Goldcoast, May 23-26, 2000. vol. 4084, 2000, pp. 783-789 (abstract only). |
Shoemaker et al., “Reflection Seismic and Ground Penetrating Radar Study of Previously Mined (Lead/Zinc) Ground”, Joplin, Missouri, Missouri Department of Transportation special publication, 2000, 15 pages. |
Tektronix, “Generating Advanced Radar Signals Using Arbitrary Waveform Generators”, www.tektronix.com/signal—generators. 26 pages, 2012. |
Van der Veen et al., “Design and application of a towed land-streamer system for cost-effective 2-D and pseudo-3-D shallow seismic data acquisition”, Geophysics, vol. 66, No. 2, (Mar.-Apr. 2001), p. 482-500. |
Van Dijk et al., “Multi-mode FMCW radar array with independent digital beam steering for transmit and receive”, 2008 5th European Radar Conference (EURAD 2008); Oct. 30-31, 2008, Amsterdam, Netherlands, IEEE, Piscataway, NJ. pp. 412-415. (abstract only). |
Well et al. Investigations of Hazardous Waste Sites Using Thermal IR and Ground Penetrating Radar, Photogrammetric Engineering & Remote Sensing, vol. 60, No. 8, Aug. 1994, pp. 999-1005. (Abstract only). |
White, “Building an Urban Image.” Archeologia e Calcolatori (International Association of Computing in Archaeology, Rome Italy), vol. 7, 1996, 137-147 (abstract only). |
Yasunaga et al., “Design, Fabrication and Evaluation of a 5-inch Wafer Scale Neural Network LSI Composed of 576 Neurons”, IEEE International Joint Conference on Neural Networks, vol. II, 1990, pp. 527-535. |
Yoder et al., “Mapping agricultural fields with GPR and EMI to predict offsite movement of agrochemicals”, Proc. SPIE, vol. 4084, 20, 2000, abstract only. |
CHEMRAD Tennessee Corporation, USRADS Series 2100, Brochure (no copy available). |
Geophysical Survey Systems, Inc.,RADAN™—Radar Data Analyzer, Production Information Sheet, Jan. 1993 (no copy available). |
Geophysical Survey Systems, Inc., Subsurface Solutions, Winter 1995. (no copy available). |
Geophysical Survey System, Inc., SIR® System-2 Subsurface Interface Radar, Brochure (no copy available), 1995. |
Geophysical Survey System, Inc., SIR® System-10A Subsurface Interface Radar, Brochure (no copy available), 1995. |
Geophysical Survey System, Inc., SIR® System Antennas, Brochure (no copy available), 1995. |
Geophysical Survey System, Inc., Model 3200MLF, Multiple, Low-Frquency, Bistatic Antenna, Brochure (no copy available), 1995. |
Geophysical Survey System, Inc., Subsurface Detection Problems, Brochure (no copy available), 1995. |
GeoRadar, Inc., Model 1000B, Stepped-FM Ground Penetrating Radar, Brochure (no copy available). |
Pollution Engineering, Peering Beneath the Surface, Article, Oct. 1992. (no copy available). |
Sensors & Software, Inc., Pulse™ 100, Features, Brochure (no copy available), 1994. |
Sensors & Software, Inc., Pulse EKKO™ 100, Ground Penetrating Radar Technology, Brochure. (no copy available), 1994. |
Sensors & Software, Inc., Pulse EKKO™ 100, Case Studies, pp. 80-83, 87-94, 98, 100, 129, 131. (no copy available), 1994. |
Sensors & Software, Inc., Pulse EKKO™ 1000, Brochure. (no copy available), 1994. |
Sensors & Software, Inc., Pulse EKKO™, Environment, Feb. 1994. (no copy available). |
International Search Report and Written Opinion dated Jun. 14, 2013 for PCT Application No. PCT/US2013/030618, 14 pages, Apr. 7, 2003. |
Number | Date | Country | |
---|---|---|---|
20130234879 A1 | Sep 2013 | US |
Number | Date | Country | |
---|---|---|---|
61609715 | Mar 2012 | US |