GPS World

Category: Receivers

  • Innovation: Evolutionary and revolutionary

    Innovation: Evolutionary and revolutionary

    The development and performance of the VeraPhase GNSS antenna

    By Julien Hautcoeur, Ronald H. Johnston and Gyles Panther

    INNOVATION INSIGHTS with Richard Langley
    INNOVATION INSIGHTS with Richard Langley

    ANTENNAS MATTER. Often overlooked by the casual user of a GNSS receiver, its antenna is a critical component of the system. In the case of consumer equipment such as handheld receivers, satellite navigation units and embedded devices inside smartphones, cameras and fitness monitors, the antenna might not even be visible. Nevertheless, a GNSS antenna must be carefully designed and constructed to maximize the transfer of the electromagnetic energy of the weak GNSS signals into an electrical current that can be fed to the receiver. Typically, this means that the antenna has to be designed for reception of the right-hand circularly polarized signals transmitted by the satellites on their particular frequency or frequencies. Some mass-produced embedded devices might use less efficient linearly polarized antennas coupled with a high-sensitivity receiver simply to shave a few cents off the cost of the units or to fit them into a limited volume. But the pros and cons of such antennas is a discussion for another time.

    A GNSS antenna must also be omnidirectional, being able to receive signals arriving from any azimuth and elevation angle with acceptable gain in the hemisphere above the antenna while rejecting those signals arriving from below the antenna that, in most cases, are undesirable reflections off the ground and which have a large left-hand circularly polarized component. Reflected signals from the ground or other surfaces combine with the line-of-sight signals from the satellites resulting in multipath interference, which contaminates pseudorange and carrier-phase measurements. The first line of defense against multipath is a multipath-resistant antenna. Signals from non-GNSS transmitters on nearby frequencies should also be rejected so as not to cause interference to the receiver or overload its front end.

    An important characteristic for precision GNSS applications is stable electrical phase centers—the locations in three-dimensional space to which GNSS measurements are referenced. Ideally, they would be perfectly fixed with respect to the antenna housing but, in reality, they will vary with the direction of the arriving GNSS signals. The variation, however, should be small, repeatable and calibrated with the calibration values available for data-processing software.

    It was about 40 years ago when the first GPS receiving antennas were developed and there have been many significant advances in antenna design and fabrication since then. You might be tempted to think that there is nothing new in the research and development of GNSS antennas. You would be wrong.

    In this month’s column, we take a look at a revolutionary design of a multi-frequency multi-GNSS antenna. Our authors discuss how the antenna evolved from a research project in academia to a commercial product about to enter the market. And, like a number of GNSS advances, it’s Canadian, eh?

    The use of GNSS technology has permeated many aspects of life today. With each advancement in the technology, new applications become possible as a result of lowered costs, smaller size, greater capabilities, and higher precision and accuracy. In particular, advances in antenna technology can provide greater capabilities to GNSS receiving equipment.

    In this article, we report on the research and commercial development of a high-performance GNSS antenna that can cover all of the GNSS frequency bands, that has high purity circularly polarized radiation, high phase-center stability and high radiation efficiency. Early numerical simulations showed that the turnstile/cup antenna was a good starting point for this research. For GNSS applications, this antenna type required much further research to extend the impedance bandwidth, to reduce cross-polarization and to reduce backward radiation. Many thousands of electromagnetic (EM) computer simulations and optimizations of various circular waveguide (or cup) structures led to a high-performance circularly polarized antenna.

    This antenna has excellent axial ratios in all theta and phi directions, low backward radiation, excellent phase-center stability and a compact design. Intermediate and final antenna designs were extensively tested in the anechoic chamber of the Schulich School of Engineering at the University of Calgary. Our company subsequently signed a license agreement with the University of Calgary’s University Technologies International Inc. and undertook further development of the antenna for commercial production. In this article, we present measured results for the resulting commercial antenna known as the Tallysman VeraPhase VP6000 antenna.

    Early Circularly Polarized Antennas. One of the first circularly polarized antenna designs (1948) can be attributed to Sichak and Milazzo (see Further Reading), who introduced the turnstile or crossed-dipole circular polarization (CP) antenna. The crossed dipoles must have current flows that are 90 degrees out of phase with each other. This phase difference can be achieved feeding the two dipoles 90 degrees out of phase by a phase-shifting signal splitter or by changing the impedance of each of the dipoles. The turnstile antenna produces highly pure CP only in the two directions normal to the two dipoles. If the dipoles are normal to each other and lie in the horizontal plane, they can radiate right-hand circular polarization (RHCP) upwards while left-hand circular polarization (LHCP) is radiated downwards. At the horizon, they will radiate only a linear horizontally polarized wave. For GNSS applications, this is a serious limitation. By 1973, it was known that a horizontal dipole placed near the open face of a “cup” or shorted waveguide would radiate a linear horizontally polarized wave sideways and a vertically polarized wave in its direction of alignment. These properties were utilized by Epis (see Further Reading) to build a broadband CP antenna.

    RESEARCH OBJECTIVE

    The university research project began with the objective of developing a high-precision GNSS antenna that would cover all of the frequency bands being considered by the various national GNSS satellite systems, whether launched or under development. It was decided at the onset of the research that computer simulation and optimization methods would be an important part of the research endeavor. Many antenna structures were evaluated using EM simulation tools. Various structures were constructed in software and then simulated. Early simulations indicated that the crossed dipole placed in a cup offered the best possibility for producing a high-performance GNSS antenna. To obtain the best RHCP with minimal LHCP, it became necessary to place the dipoles somewhat within the cup. Nevertheless, the impedance bandwidth of this configuration is insufficient to handle the upper and lower GNSS frequency bands at the same time.

    Extending the Antenna Bandwidth. The first structure that was used to handle both the L1 and L2 GNSS bands was a second set of dipoles connected in parallel to the first set. This arrangement provided an adequate match to frequencies close to the L1 band (1575 MHz) and the L2 band (1227 MHz) but it gave a rapidly changing reflection coefficient close to and below the L1 band. The two dipole sets were fed by an appropriate surface-mount 90-degree hybrid coupler designed for the required broad frequency band. The dipoles are fed by microstrip via “grounded legs” that are built on printed circuit board (PCB) technology. Good performance was achieved with this structure, but further improvements in the performance were actively sought. The two dipoles connected directly together cause a deep notch in the radiated signal at a frequency close to and below the L1 band. This was considered to be undesirable. It was decided to use a coupled resonant radiating structure tuned to L1 while the main dipoles would be tuned to L2 (see FIGURE 1).

    FIGURE 1. An extended bandwidth GNSS antenna. The lower and connected dipoles are tuned to L2 and the upper coupled shorted dipoles are tuned to L1. Current flow in the circular waveguide of the GNSS antenna is shown. Strong circumferential currents flow at the top of the waveguide. Red indicates large currents and the arrows show the directions of the current flow.
    FIGURE 1. An extended bandwidth GNSS antenna. The lower and connected dipoles are tuned to L2 and the upper coupled shorted dipoles are tuned to L1. Current flow in the circular waveguide of the GNSS antenna is shown. Strong circumferential currents flow at the top of the waveguide. Red indicates large currents and the arrows show the directions of the current flow. (Image: Julien Hautcoeur, Ronald H. Johnston and Gyles Panther)

    It is well known that resonant circuits can be broadbanded by choosing the correct coupling between them. This was tried in software and found to give an excellent wideband response.

    Circumferential Current Reduction. Through many EM simulations of the antenna structure, it was found that the LHCP could be suppressed substantially by making the aperture of the cup serrated. The EM wave simulation package allows the user to look at the currents in the structure. The results are shown in FIGURE 2.

    FIGURE 2. An antenna with a tapered base and a sawtooth aperture, which reduces circumferential current flow.
    FIGURE 2. An antenna with a tapered base and a sawtooth aperture, which reduces circumferential current flow. (Image: Julien Hautcoeur, Ronald H. Johnston and Gyles Panther)

    The strong circumferential currents (horizontal linear currents) produce radiation with linear horizontal polarization. It is important to reduce the size of these currents to minimize the linearly polarized radiation. The horizontal currents flowing in the top of the waveguide wall are effective in setting up horizontal polarization (HP) radiation in the direction of the horizon. For high-quality CP radiation, the horizontal radiation must be matched by vertical radiation (with a 90-degree phase shift), but the waveguide wall does not permit the required vertical current to flow to produce the vertical polarization (VP) radiation component. Clearly, a serrated waveguide aperture reduces the circumferential current flow. It was also found, through many simulations, that the unwanted polarization components can be reduced by tapering the cup towards the bottom end (see Figure 2).

    The sawtooth aperture antenna was chosen for further development. The fed dipoles are constructed using PCB technology and are given shapes that vary from the wire dipole case. The radiating resonator is also constructed using PCB material and is given a different shape from the pure straight-wire case. The software antenna was constructed and tested and found to have good performance with regard to low cross polarization in all directions, low backward radiation and high radiation efficiency.

    Further Waveguide Development. It was decided that another way of achieving vertical currents and horizontal currents that would be balanced in magnitude and have a 90-degree phase difference might be obtained by constructing the waveguide walls from a combination of thin conductors connected in a grid. The grid consists of a combination of vertical and horizontal conductors. Simulations with EM software showed the antenna is exceptionally efficient when it uses wires. The wire grid waveguide model of the GNSS antenna was simulated with many, many topological variations. Each variation was optimized for low back (nadir) radiation and high-purity RHCP in all directions. The results were unexpected. The best results were obtained when only one circumferential wire conductor is used and, furthermore, the vertical wire conductors are not connected to the circumferential conductor nor to the base of the antenna. This structure was simulated and optimized many times to derive the best possible topological configuration and component dimensions for a GNSS antenna. A PCB model of the GNSS antenna was then numerically constructed, simulated and optimized as a more practical construction technology for the antenna (see FIGURE 3).

    FIGURE 3. The conducting plate waveguide model of the GNSS antenna. The blue plates are conducting sheets and the yellow plates are the dielectric of the PCB.
    FIGURE 3. The conducting plate waveguide model of the GNSS antenna. The blue plates are conducting sheets and the yellow plates are the dielectric of the PCB. (Image: Julien Hautcoeur, Ronald H. Johnston and Gyles Panther)

    Note that the vertical strip conductors do not contact the conducting antenna base. Also note the serrated antenna base, as seen on the inside of the antenna. This design feature reduces excessive circumferential current flow in the base of the antenna. The antenna was tested in the University of Calgary anechoic chamber and in the high-quality Simon Fraser University anechoic chamber (a Satimo SG64), and it was found to have well-suppressed LHCP radiation, very low back radiation and very stable phase centers.

    The unique topology of this last antenna provides suppression of the expected downward LHCP radiation that most CP antennas exhibit. Radiation tends to “spill over” from the aperture and travel downwards. Downward radiation also emerges from the gap between the antenna base and the vertical conductors. These two sources of downward radiation are largely out of phase and tend to cancel each other out. This reduced downward LHCP radiation largely removes the need for a choke ring to block the reflections from the ground. This in turn means that the antenna can be compact and light.

    ANTENNA DEVELOPMENT

    Tallysman's VeraPhase 6000 high-precision GNSS antenna.
    FIGURE 4.  Tallysman’s VeraPhase 6000 high-precision GNSS antenna. (Photo: Tallysman)

    We undertook the project of converting the research prototype antenna described above into a commercially viable product. The research prototype antenna was modified to achieve optimized gain at lower GNSS frequencies, high mechanical robustness, adaptation for efficient manufacturability and for use of different materials. This antenna is known as the VeraPhase VP6000 antenna and is shown in FIGURE 4.

    The topology of the antenna follows that of the research prototype with dimensional adjustments so as to function correctly with the new materials and circuitry being used. It is light and compact with a diameter of 157 millimeters, a height of 137 millimeters and a weight of less than 670 grams.

    VeraPhase Measurements. Anechoic chamber tests were conducted at the Satimo facility in Kennesaw, Georgia, to determine the gain pattern, axial ratio, phase-center offset and variation in multipath-free conditions. Data were collected from 1160 MHz to 1610 MHz to cover all the GNSS frequencies.

    Antenna Gain, Efficiency and Roll-off. The chamber measurements show that the VP6000 exhibits a gain at zenith from 4.9 dBic at 1164 MHz to 7.05 dBic at 1610 MHz (see FIGURE 5). This high gain in combination with a wideband pre-filtered low-noise amplifier (LNA) with a noise figure of 2 dB provides for high carrier-to-noise density (C/N0) ratios for all GNSS frequencies. Furthermore, the VP6000 exhibits gain at the horizon from –4.4 dBic at 1164 MHz to –6.8 dBic at 1610 MHz (see Figure 5).

    FIGURE 5. RHCP gain of the VP6000 at zenith and the horizon at all GNSS frequencies.
    FIGURE 5. RHCP gain of the VP6000 at zenith and the horizon at all GNSS frequencies. (Image: Julien Hautcoeur, Ronald H. Johnston and Gyles Panther)

    Thus, the gain roll-off from zenith to horizon is between 10.1 dB and 13.6 dB, providing for good tracking at low elevation angles. The radiation efficiency of the VP6000 is 70 percent to 80 percent, corresponding to an inherent (“hidden”) loss of just 1 dB to 1.5 dB, which includes all feedline, matching circuit and 90-degree hybrid coupler losses. In contrast, spiral antennas usually exhibit an inherent efficiency loss of close to 4 dB in the lower GNSS frequencies. Thus, with a high performance LNA, high values of gain translate into higher C/N0 ratios.

    FIGURE 6. Normalized radiation patterns of the VP6000 on 60 phi cuts of the GPS frequency bands.
    FIGURE 6. Normalized radiation patterns of the VP6000 on 60 phi cuts of the GPS frequency bands. (Image: Julien Hautcoeur, Ronald H. Johnston and Gyles Panther)

    Radiation Patterns. The radiation pattern of an idealized antenna would have pure CP and constant high gain from zenith down to the horizon and then roll off rapidly for elevation angles below the horizon. In a realizable antenna, the gain should be close to constant over all azimuths for each elevation angle, with strong cross-polarization rejection over that frequency range. The phase-center offset should be stable with minimal phase-center variation. In the upper hemisphere, the greater the difference between the RHCP and LHCP antenna gain, the greater the resistance of the antenna to cross-polarized signals, usually associated with odd order reflections, and hence improved multipath signal rejection. The measured radiation patterns at GPS frequencies are shown in FIGURE 6.

    The radiation patterns are normalized to enable direct comparison of the patterns and show the RHCP and LHCP gains on 60 azimuth cuts three degrees apart. The radiation patterns show excellent suppression of the LHCP signals in the upper hemisphere. Similar results were found for all the other GNSS frequencies. The difference between the RHCP gain and the LHCP gain at zenith ensures an excellent discrimination ranging from 31 dB to 53 dB. Also, for the other elevation angles the LHCP signals usually stay 25 dB below the maximum RHCP gain and even 30 dB from 1200 MHz to 1580 MHz. The antenna shows a constant amplitude response to signals coming at a constant elevation angle regardless of the azimuth or bearing angle. This illustrates the excellent multipath mitigation characteristics of the VP6000 at every elevation angle and every GNSS frequency.

    Down-Up Ratio. When a direct satellite signal is reflected from the ground, the reflected signal polarization tends to convert, at least partially, from RHCP to LHCP for most soil types. If the terrain underneath the antenna is homogeneous, then the ground surface acts as a mirror, thus providing a reflected signal coming from below the horizon at the negative of the angle of the direct signal above the horizon. Depending on the angle, in part, the field of the inverted and reflected wave adds to the direct wave, which is undesirable. This is the reason, when characterizing the multipath reflection capabilities of an antenna, it is common to use a down-up ratio between antenna gain for LHCP signals for a given angle below the horizon as that for the RHCP signals at the same angle above the horizon. The down-up ratios at L2 and L1 are –25 dB at zenith and they stay under –20 dB for the upper hemisphere, which is usually not the case for standard GNSS antennas. Similar results have been measured over the whole range of GNSS frequencies and confirm the excellent multipath rejection capabilities of the VP6000.

    Axial Ratio. The axial ratio (AR) is a measure of an antenna’s ability to reject the cross-polarized portion of a composite signal with both RHCP and LHCP components. Physically, this is an elliptical wave, typically being the combination of the direct and reflected signals from the satellite. The lower the ratio of the major axis to the minor axis of the polarization ellipse, the better the multipath rejection capability of the antenna. To meet operational standards for a multi-band antenna, the axial ratio should meet these requirements at the following elevation angles:

    • 45–90 degrees: not to exceed 3 dB
    • 15–45 degrees: not to exceed 6 dB
    • 5–15 degrees: not to exceed 8 dB.

    The worst AR ratio values of the VP6000 at different elevation angles have been plotted in FIGURE 7. The graph shows an AR of less than 0.5 dB at zenith for all GNSS frequencies, and the ARs stay low at all elevation angles down to the horizon. A maximum value of 1.5 dB has been measured for elevation angles above 30 degrees, increasing to just 2 dB at the horizon (0 degree elevation angle) for the worst case azimuth. This performance contributes to the excellent multipath rejection capability of the VP6000.

    FIGURE 7. Worst case of axial ratios of the VP6000 at different elevation angles: 90 degrees (zenith), 30 degrees, 10 degrees and 0 degrees (horizon).
    FIGURE 7. Worst case of axial ratios of the VP6000 at different elevation angles: 90 degrees (zenith), 30 degrees, 10 degrees and 0 degrees (horizon). (Image: Julien Hautcoeur, Ronald H. Johnston and Gyles Panther)

    Phase-Center Offset / Phase-Center Variation and Absolute Calibration. For use as a measurement instrument, the antenna must have a precise origin, equivalent to a tape measure zero mark. Thus, it is important that the phase of the waves received by the antenna “appear” to arrive at a single point that is independent of the elevation angle and azimuth of the incoming wave. This point is known as the phase center of the antenna, which should remain fixed for all operational frequencies and for all azimuth and elevation angles of incoming waves, otherwise dimensional measurement is compromised.

    In an ideal GNSS antenna, the phase center would correspond exactly with the physical center of the antenna housing. In practice, it varies with the changing azimuth and elevation angle of the satellite signal. The difference between the electrical phase center and an accessible location amenable to measurement on the antenna is described by the phase-center offset (PCO) and phase-center variation (PCV) parameters and their values are determined through antenna calibration.

    These corrections are only effective if the predicted phase-center movement is repeatable for all antennas of the same model. The PCO is calculated for each measured elevation angle by considering the signal phase output for all phi (azimuth) values at a specific theta (elevation) angle, and mathematical removal of the normal phase-windup effect in this type of antenna.

    A Fourier analysis is then conducted on this resulting data. The fundamental output gives the variation of the horizontal position of the antenna as it is rotated about the z axis. The apparent position normally varies somewhat as the antenna is viewed from various theta angles. The PCV measurement of the VP6000 showed the variation of the phase center in the horizontal plane for elevation angles of 18 to 90 degrees in 3-degree steps at different frequencies. The variations for the different GNSS signals are typically less than 1 millimeter from the x and y axes. Repeatability of the PCO and PCV over several VP6000 antennas has been measured and is also less than 0.5 millimeters.

    Five copies of the antenna were sent for absolute calibration by Geo++ in Germany where the VP6000 has been calibrated at GPS L1/L2 and GLONASS G1/G2 signal frequencies. The PCV for the upper hemisphere of the VP6000 at L1 and L2 are plotted in FIGURES 8 and 9. These results confirm a ±1-millimeter PCV at L1 and a ±1-millimeter PCV at L2. Also the standard deviation of the PCV over the five measured antennas stayed under 0.2 millimeters, which represents excellent repeatability. The same results have been observed at G1 and G2.

    FIGURE 8. Phase-center variation at L1. The same results have been observed at G1.
    FIGURE 8. Phase-center variation at L1. The same results have been observed at G1. (Image: Julien Hautcoeur, Ronald H. Johnston and Gyles Panther)
    FIGURE 9. Phase-center variation at L2. The same results have been observed at G2.
    FIGURE 9. Phase-center variation at L2. The same results have been observed at G2. (Image: Julien Hautcoeur, Ronald H. Johnston and Gyles Panther)

    LNA and Optional Circuitry. The best achievable C/N0 for signals with marginal power flux density is limited by the efficiency of each antenna element, the gain and the overall receiver noise figure. This can be quantified by a ratio parameter, usually referred to as G/T, where G is the antenna gain (in a specific direction) and T is the effective noise temperature of the receiver — usually dominated by the noise figure of the input LNA.

    In the VP6000 LNA, the received signal is split into the lower GNSS frequencies (from 1160 MHz to 1300 MHz) and the higher GNSS frequencies (from 1525 MHz to 1610 MHz) in a diplexer connected directly to the antenna terminals and then pre-filtered in each band. This is where the high gain and high efficiency of the basic VP6000 antenna element provides a starting advantage, since the losses introduced by the diplexer and filters are offset by the higher antenna gain, thereby preserving the all-important G/T ratio.

    That being said, GNSS receivers must accommodate a crowded RF spectrum, and there are a number of high-level, potentially interfering signals that can saturate and desensitize GNSS receivers. These include, for example, the Industrial, Scientific and Medical (ISM) band signals and mobile phone signals, particularly Long-Term Evolution (LTE) signals in the newer 700-MHz band, which are a hazard because of the potential for harmonic generation in the GNSS LNA. Other potentially interfering signals include Globalstar (1610 MHz to 1618.25 MHz) and Iridium (1616 MHz to 1626 MHz) because they are high-power uplink signals and particularly close in frequency to GLONASS signals. The VP6000 LNA is a compromise between ultimate sensitivity and ultimate interference rejection.

    A first defensive measure in the VP6000 LNA is the addition of multi-element bandpass filters at the antenna element terminals (ahead of the LNA). These have a typical insertion loss of 1 dB because of their tight passband and steep rejection characteristics. Sadly, there is no free lunch, and the LNA noise figure is increased approximately by the additional filter-insertion loss.

    The second defensive measure in the VP6000 LNA is the use of an LNA with high linearity, which is achieved without any significant increase in LNA power consumption, by use of LNA chips that employ negative feedback to provide well-controlled impedance and gain over a very wide bandwidth with considerably improved linearity.

    Bear in mind that while an installation might initially be determined to have an uncluttered environment, subsequent introduction of new services may change this, so interference defenses are prudent even in a clean environment. A potentially undesirable side effect of tight pre-filters is the possible dispersion that can result from variable group delay across the filter passband. Thus it is important to include these criteria in selection of suitable pre-filters. The filters in the VP6000 LNA give rise to a maximum variation of 2 nanoseconds in group delay over the lower GNSS frequencies (from 1160 MHz to 1300 MHz) and 2.5 nanoseconds over the higher GNSS frequencies (from 1525 MHz to 1610 MHz). Also, the difference in group delay between the lower GNSS frequencies and the higher GNSS frequencies stays less than 5 nanoseconds.

    The VP6000 series antennas are available with either a 35-dB gain LNA or with a 50-dB gain LNA for installations with long coaxial cable runs. The VP6000 is internally regulated to allow a supply voltage from 2.7 volts to 26 volts.

    An interesting feature of the VP6000 is that the physical housing includes a secondary shielded PCB that is available for integration of custom circuits or systems within the antenna. This allows the addition of L1/L2 receivers for real-time kinematic operation, for example. A pre-filtered, 15-dB pre-amp version of the LNA is also available to provide RF input for OEM systems embedded within the antenna housing.

    The VP6000 is available with a variety of connectors and with a conical radome to shed ice and snow and to deter birds for reference antenna installations. A precise and robust monument mount is also available.

    CONCLUSION

    In this article, we have described a research program that developed a series of CP antennas, which have increasingly improved performances directed towards GNSS applications. The resulting research CP prototype antenna has a very low cross-polarization, very low back radiation, very high phase-center stability and a compact structure. We have converted the research prototype into a commercially viable GNSS antenna with the superior electrical properties of the research prototype while building into the antenna the required physical ruggedness and manufacturability required of the commercial antenna.

    With emerging satellite systems on the horizon, a new high-performance antenna is needed to encompass all GNSS signals. Our new antenna has sufficient bandwidth to receive all existing and currently planned GNSS signals, while providing high performance standards. Testing of the antenna has shown that the new innovative design (crossed driven dipoles associated with a coupled radiating element combined with a high performance LNA) has good performance, especially with respect to axial ratios, cross-polarization discrimination and phase-center variation.

    These improvements make the antenna an ideal candidate for low-elevation-angle tracking. The reception of the proposed new signals along with additional low-elevation-angle satellites will bring new levels of positional accuracy to reference networks, and benefits to the end users of the data. With its compact size and light weight, the antenna has been designed and built for durability and will stand the test of time, even in the harshest of environments.

    ACKNOWLEDGMENT

    This article is based, in part, on the paper “The Evolutionary Development and Performance of the VeraPhase GNSS Antenna” presented at the 2016 International Technical Meeting of The Institute of Navigation held in Monterey, California, Jan. 25–28, 2016.

    JULIEN HAUTCOEUR graduated in electronics systems engineering and industrial informatics from the Ecole Polytechnique de l’Université de Nantes, Nantes, France, and received a master’s degree in radio communications systems and electronics in 2007 and a Ph.D. degree in signal processing and telecommunications from the Institute of Electronics and Telecommunications of Université de Rennes 1, Rennes, France, in 2011. From 2011 to 2013, he obtained postdoctoral training with the Université du Québec en Outaouais, Gatineau, Canada. In 2014, he joined Tallysman Wireless Inc. in Ottawa, Canada, as an antenna and RF engineer.

    RONALD H. JOHNSTON received a B.Sc. from the University of Alberta, Edmonton, Canada, in 1961 and the Ph.D. and D.I.C. from the University of London and Imperial College (both in London, U.K.) respectively, in 1967. In 1970, he joined the University of Calgary, Canada, and has held assistant to full professor positions and was the head of the Department of Electrical and Computer Engineering from 1997 to 2002. He became professor emeritus in the Schulich School of Engineering in 2006.

    GYLES PANTHER is a technology industry veteran with more than 40 years of engineering, corporate management and entrepreneurial experience. He spent the first 20 years of his career in the semiconductor industry, first with Plessey in the U.K., then in Canada with Microsystems International. Panther co-founded and acted as engineering vice president and chief technology officer (CTO) for Siltronics, followed by SilCom and SiGem. In 2002, he founded startup Wi-Sys Communications, acting as president and CTO. He is now president and CTO of Tallysman Wireless, his fourth successful start-up, which was founded in 2009. Panther holds an honours degree in applied physics from City University, London, U.K.

    FURTHER READING

    • Authors’ Conference Paper

    “The Evolutionary Development and Performance of the VeraPhase GNSS Antenna” by J. Hautcoeur, R.H. Johnston and G. Panther in Proceedings of ITM 2016, the 2016 International Technical Meeting of The Institute of Navigation, Monterey, California, Jan. 25–28, 2016, pp. 771–783.

    • Early Circularly Polarized Antenna Designs

    “Broadband Cup-Dipole and Cup-Turnstile Antennas” by J.J. Epis, United States Patent No. 3,740,754, June 19, 1973.

    “Antennas for Circular Polarizations” by W. Sichak and S. Milazzo in Proceedings of the Institute of Radio Engineers, Vol. 36, No. 8, Aug. 1948, pp. 997–1001, doi: 10.1109/JRPROC.1948.231947.

    • Antenna Modeling

    Electromagnetic Modeling of Composite Metallic and Dielectric Structures by B.M. Kolundzija and A.R. Djordjevi, published by Artech House, Norwood, Massachusetts, 2002.

    WIPL-D: Electromagnetic Modeling of Composite Metallic and Dielectric Structures – Software and User’s Manual by B.M. Kolundzija, J.S. Ognjanovic and T.K. Sarkar, published by Artech House, Norwood, Massachusetts, 2000.

    • Measurement of Phase Center and Other Antenna Characteristics

    “Determining the Three-Dimensional Phase Center of an Antenna” by Y. Chen and R.G.Vaughan in Proceedings of the XXXIth General Assembly and Scientific Symposium of the International Union of Radio Science (URSI), Beijing, Aug. 16–23, 2014, doi: 10.1109/URSIGASS.2014.6929023.

    “Calibrating Antenna Phase Centers: A Tale of Two Methods” by B. Akrour, R. Santerre and A. Geiger in GPS World, Vol. 16, No. 2, Feb. 2005, pp. 49–53.

    “Characterizing the Behavior of Geodetic GPS Antennas” by B.R. Schupler and T.A. Clark in GPS World, Vol. 12, No. 2, Feb. 2001, pp. 48–55.

    • The Basics of GNSS Antennas

    “GNSS Antennas: An Introduction to Bandwidth, Gain Pattern, Polarization, and All That” by G.J.K. Moernaut and D. Orban in GPS World, Vol. 20, No. 2, Feb. 2009, pp. 42–48.

    “A Primer on GPS Antennas” by R.B. Langley in GPS World, Vol. 9, No. 7, July 1998, pp. 73–77.

  • Receiver Design for the Future

    Sponsored by: NavCom
    Broadcast date: Thursday, January 15, 2015
    On-Demand Available Until: Friday, January 15, 2016
    Moderator: Alan Cameron, Group Publisher, GPS World and Geospatial Solutions
    Speaker: Greg Turetzky, Principal Engineer at Intel
    Summary: The compound annual growth rate of GNSS devices will continue, from its current 22 percent level to a robust 9 percent for the years 2016–2022, and heading for seven billion installed units by 2022. The design challenges for GNSS are to:

    • Take advantage of smaller geometries to achieve higher clock speeds, more memory, lower active power and smaller size, while reducing standby power from leakage;
    • Incorporate new methodologies in chip and system design; integrate multiple radios on a single die to reduce cost and size;
    • Integrate multiple radio sources into a single location solution;
    • Bring together a disparate value chain.

    The technology roadmaps embrace most modalities of positioning: GNSS, Bluetooth, Wi-Fi, cellular, and SBAS, and cross most platforms, including wearables.

    Register now to learn how SiRFusion will enable new services, applications and social media for you.

  • GNSS Receiver Design: New MEMS Components, Optimal Search Strategies

    Broadcast Date: January 21, 2016
    On-Demand Available Until: January 21, 2017
    Sponsor: NovAtel
    Moderator: Alan Cameron, Editor-In-Chief and Publisher, GPS World
    Speakers: Mark Petovello, Professor, University of Calgary; Esther Anyaegbu, Senior Systems Architect, Intel Mobile Communications; Matthias Overbeck, Group Manager of the Precise GNSS Receiver Program at the Fraunhofer Institute for Integrated Circuits; Sandy Kennedy, Director and Chief Engineer of Core Cards, NovAtel Inc.
    Summary: The world of GNSS receiver design is a bit like a chocolate cake in the oven: rich, dense, and constantly expanding. To cover our topic adequately within only 60 minutes, we encompass a number of new and not necessarily related approaches and research areas. We’ll have three or four speakers, each presenting for 10 to 12 minutes, leaving a good quarter hour for your questions and their expert responses. This webinar will cover MEMS Oscillators on the Move and Optimal Search Strategies in a Multi-constellation Environment.

  • Trimble R2 GNSS receiver now available through Esri

    Esri has made available the Trimble R2 GNSS receiver for collecting professional-grade GPS data with Collector for ArcGIS.

    The GNSS receiver is rugged certified MIL-STD-810G, IP65 rated and compact, Esri says in a news release. The receiver is capable of delivering submeter and centimeter positioning accuracy in real-time to Android or iOS mobile devices via a wireless Bluetooth connection, or USB cable, to support geographic information system (GIS) or survey-grade workflows.

    “Today’s geospatial professionals require flexible solutions which allow for configuration to meet their specific job requirements,” says Ron Bisio, vice president of Trimble’s surveying and geospatial Division. “By offering a complete, integrated solution, Esri and Trimble enable our joint customers to build a better and more reliable asset inventory using the mobile device, workflow and accuracy they choose.”

    With the upcoming high-accuracy improvements to the Collector for ArcGIS App, Esri says the Trimble R2 GNSS receiver provides total flexibility to choose a solution based on the accuracy and GNSS performance level that suits the application. Now the locational precision of mobile devices can be enhanced via the Trimble R2 GNSS receiver. It is capable of supporting multiple global satellite constellation systems, including GPS, GLONASS, Galileo and BeiDou, and delivers GNSS positions in real time without the need for post-processing.

    “Collector for ArcGIS is used by organizations to collect and update GIS data in the field,” says Dean Garner, Esri hardware solutions manager. “Many of our customers like the ease of use of Collector for ArcGIS on consumer handheld devices. Paired with the Trimble R2 GNSS receiver and the upcoming high-accuracy enhancements of Collector for ArcGIS 10.4, users can capture GIS data on their smartphones and tablets that meets the more stringent accuracy requirements of their organization.”

    Designed for GIS professionals in a variety of organizations, the stand-alone Bluetooth or USB connected Trimble R2 GNSS receiver enables users to collect high-accuracy location data with Collector for ArcGIS on existing technology — whether it’s a modern smart device, such as a mobile phone or tablet, or a traditional integrated data collection handheld or tablet. The receiver can be pole mounted or carried in a backpack.

  • Harxon releases new GNSS + L-band antenna

    Harxon releases new GNSS + L-band antenna

    Harxon, a high-precision GNSS antenna manufacturer in China, has released a new GNSS + L-band antenna.

    The GPS1000 receives GPS L1/L2/L5, BDS B1/B2/B3, GLONASS L1/L2, Galileo E1/E2/E5a/E5b and L-band frequencies, which can be used in land survey, marine survey, channel survey, seismic monitoring, bridge survey, container operation and agriculture applications. Customers can use the same antenna for GPS only or dual-constellation applications.

    It has high gain and wide beam width to ensure the signal receiving performance of satellite at low elevation angle. The phase center of this antenna remains constant as the azimuth and elevation angle of the satellites change. Signal reception is unaffected by the rotation of the antenna or satellite elevation, so placement and installation of the antenna can be completed with ease.

    The GPS1000 is housed in a IP67 waterproof enclosure for permanent installation, and maintains good performance in a variety of harsh environments. Plus, it can be customized by Harxon for the best solution for customers. Orders can be placed at www.harxon.com.

    The new Harxon GPS1000 antenna.
    The new Harxon GPS1000 antenna.

  • GEOINT 2016: The growing GEOINT revolution

    A few weeks ago, I attended GEOINT 2016. It was quite different from my first GEOINT in 2007. Back then, GIS and imagery were the focus of most exhibitors and presentations, with points, line and polygons plotted on paper being the norm. This year the tradecraft seems to have evolved exponentially to a broad and significantly more sophisticated collection of technologies both on the EXPO floor and in most presentations.

    New terms have solidly entered the geospatial lexicon: big data, big data analytics, exploiting social media, machine learning, activity based intelligence (ABI), predictive analytics (see my column last month), the internet of things (IoT) (see my January column), small sats, object based intelligence (OBI), cyber, human geography, open source, deep learning, machine to machine tipping & cueing, survivable space assets and the list continues to grow.

    I was pleased to hear something I believed for quite a while. There is a growing consensus that Cyber attacks need to be displayed as events with geospatial components (location of servers, nodes, networks, etc.). That kind of visualization should provide valuable insight into these growing and complex attacks.

    Keynotes

    National Intelligence Director James Clapper.
    National Intelligence Director James Clapper.

    The 75-year-old Director of National Intelligence (DNI) James Clapper poked fun at himself indicating that this would be his last year as DNI and he was counting down the days. He said that he was taught to always respect his elders but finding one was getting increasingly difficult. He also highlighted the same feeling I had that the GEOINT community has gone through some significant changes.

    Computers have evolved from IBM’s 1997 Deep Blue winning only one of four chess games against Gary Kasperov to the recent contest of Google AlphaGo against the world master of the much more complex Chinese board game “Go.” AlphaGo won four of five games primarily with moves that experts called inspired genius. It did that because it was programed not to just play but to learn as it played. So “machine learning” was a frequent topic at GEOINT with it becoming a real game changer in national intelligence work.

    Even imagery, the long standing bread and butter of GEOINT, is going through a revolutionary change. Citing NGA Director Cardillo, DNI Clapper indicated that we will soon evolve from limited overhead imagery available in certain locations at certain times to imagery of every spot on the globe every day of the year. You can watch Director Clapper’s full keynote.

    NOTE: More than 127 GEOINT related videos are posted on the USGIF website from the 2016 conference and the previous year with additional videos posted almost weekly. https://vimeo.com/trajectoryonlocation/videos/page:1/sort:date
    https://vimeo.com/trajectoryonlocation/videos/page:2/sort:date

    USGIF Award Winners

    The five USGIF award winners for 2016.
    The five USGIF award winners for 2016.

    Five awards were presented for 2016. Two of them had special interest for me — the Industry award winner ABACO Group shown in the EXPO section below and GeoHuntsville. Here is more information about the five USGIF award winners.

    Community Support Achievement Award for the GeoHunstville Exemplar City program

    GeoHSV
    The GeoHunstville Exemplar City program helps cities deal with disasters using new technology. Shown receiving the award for the GeoHunstville team are Chris Johnson and Joe Francica.

    I was thrilled to see my adopted geospatial city, Huntsville, win the Community Support Achievement Award. The GeoHunstville Exemplar City program which assists local governments in preparing, responding, mitigating and avoiding natural and manmade disasters using new technology.

    The system leverages geospatial tools including the new NGA open source collaboration environment GeoQ, UAVs and a broad array of internet accessible sensors through the IoT.

    Exhibit Hall Expo

    The conference attendance was over 4,000 with 250 exhibitors on the EXPO floor. You can view the full list of exhibitors at the GEOINT2016 website or by downloading the GEOINT 2016 smart phone app. The app has more information about the exhibitors including descriptions of their technology, contact info and website links. Here are samples of booths I found especially interesting.

    ABACO Group: ABACO of in the United Kingdom and Italy, was given the 2016 USGIF Industry Achievement Award. ABACO received the award for their augmented reality (AR) “Farm Visor,” to help farmers access big data. One aspect that caught a lot of attention was their very elegant “X-ray” tablet viewer. The user holds the tablet up and adjust the “Transparency” of the wall they are viewing and it looks like you are looking through the wall. In reality you are viewing a geo-registered image of the surrounding area that seems like you are looking through the wall. Because of exhibit hall lights and screen reflections the

    CYVIZ: CYVIZ builds easy to configure tactical operations centers that can display mixed media both classified and unclassified content in a common environment.

    DIFFEO: DIFFEO is an automated search assistant that uses proprietary algorithms to speed searches of Big Data even if the operator does not know what key words need to be searched.

    Hewlett Packard Enterprise Software: HP had a virtual off road driving experience. IT was not as enjoyable as Birdly, a little sickening in fact. I was told by one of the users that the reason was poor synchronization between the goggle imagery and head movement.

    International Spy Museum: The International Spy Museum, currently located on F Street in Washington DC will soon be building a much larger facility just south of the mall. They have also received considerable new material and collections for their exhibits.

    Lead’Air: Lead’Air shows several hardware configurations to capture lidar, ortho and oblique imagery.

    LizardTech: LizardTech highlighted the new ability to handle LiDAR data and display it in various ways including DEMs.

    PitneyBowes: PitneyBowes was showing their latest lossless imagery compression tools along with extensive business intelligence data.

    PLW Modelworks and Birdly: Most users consider PLW Modelworks the gold standard of digital 3D models. The PLW booth combined their superb 3B models with a virtual reality “flying machine” called Birdly. The machine uses Occulus Rift goggles with earphones for sound and even a fan blowing wind in your face to create a fairly realistic urban flight experience. The user can bank and turn or soar by flapping the wings. I tried it and it was nice.

    SigmaSpace: SigmaSpace was showing their single photon LiDAR. Their system is supposed to do a much better job discerning first and second level returns so collecting true ground elevation under a tree canopies is faster, more accurate with greater point density. Being a green laser it may also prove more effective in littoral work.

    TerraGo: TerraGo was demonstrating Edge as a tool to simplify data collection in the field using mobile devices.

  • Tallysman expands geodetic antenna line

    Tallysman, a manufacturer of high-performance GNSS antennas, has introduced two additions to its VeraPhase line of precision antennas.

    TW6000-tallysmanThe VP6300 is a triple-band antenna for reception of GPS L1/L2/L5, GLONASS G1/G2/G3, BeiDou B1/B2 and Galileo E1/E5a+b (1165MHz to 1254MHz + 1560MHz to 1610MHz).

    The VP6200 is a dual-band antenna for reception of GPS L1/L2, GLONASS G1/G2, BeiDou B1/B2, Galileo E1 and the L-Band correction services (1195MHz to 1254MHz + 1525MHz to 1610MHz).

    Both antennas have been calibrated by the U.S. National Geodetic Survey (NGS) and are designed for high-precision applications such as real-time kinematic (RTK), precise point positioning (PPP) and other applications where precision matters.

    For OEM manufacturers, the antennas feature an available, uncommitted printed circuit board (PCB) for integration of custom electronics such as precision GNSS receivers.

    According to Tallysman, these antennas fill out the VP6x00 product family with precision at a cost-effective price point. Both of these new products feature the same patented VeraPhase technology as in the VP6000 all-band reference antenna.

    VeraPhase technology is proven to have the lowest axial ratios from horizon to horizon across all frequencies, very tight Phase Centre Variations (PCV), superior gain and extremely high efficiency.

    The new antennas feature a highly linear LNA with robust pre-filtering to minimize desensing from high-level out-of-band signals such 700MHz LTE and other cellular band signals.

     

  • Lidar drone market will be worth US$144.6 million by 2022

    According to a new market research report published by MarketsandMarkets, the Lidar drone market was valued US$16.1 million in 2015 and is estimated to reach US$144.6 million by 2022 at a compound annual growth rate (CAGR) of 35.2% between 2016 and 2022.

    The full report is titled “Lidar Drone Market by Product (Rotary Wing, and Fixed Wing), Component, Application (Corridor Mapping, Archaeology, Construction, Environment, Entertainment, and Precision Agriculture), Geography — Global Forecast to 2022,” and is available through the MarketsandMarkets website.

    The 125-page report includes and 66 market data tables and 42 figures.

    Factors such as technological superiority, encouragement from governments and institutes for adoption of lidar drones, and its use in emerging applications such as precision farming are the key drivers for the growth of the lidar drone market. The use of lidar drones for delivering products generates further opportunities for lidar drone manufacturers.

    Rotary-wing. The rotary-wing lidar drone market is expected to grow at the highest CAGR during the forecast period. The ability of rotary-wing lidar drones to take off without runways and its high degree of maneuverability are the reasons for the high growth of this market.

    Corridor mapping. The corridor mapping application held the largest share of the market in 2015. Highway corridors are built after proper planning and designing to ensure that they can withstand the pressure exerted by vehicles on a regular basis.

    As highway projects are constructed from a long-term perspective, it is necessary to conduct a thorough feasibility study of the terrain on which the highway is to be constructed. Lidar drones provide this information by building three-dimensional (3D) elevation models of the surveyed area.

    Infrastructure development is further expected to increase in coming years, which would, in turn, lead to increased usage of lidar drones for inspecting the growth of the infrastructure project. These benefits drive the market in the corridor mapping application.

    North America. The North American market held the largest share of the global lidar drone market in 2015. The increasing awareness about the benefits of lidar drones such as high accuracy and low cost is one of the reasons for the large market share of the North American lidar drone market. The use of lidar drones in precision farming is driving the lidar drone market in North America.

    Major players. The major players operating in this market are Velodyne Lidar (U.S.), Phoenix Aerial Systems (U.S), Riegl Laser Measurement Systems GmbH (Austria), SICK AG (Germany), and YellowScan (France), 3D Robotics, Inc. (U.S.), DJI (China), FARO Technology (U.S.), Leica Geosystems AG (Switzerland), Optech, Inc. (Canada) and Trimble Navigation Limited (U.S.).

    The research report categorizes the global lidar drone market on the basis of components, products, applications and geography. It describes the drivers, restraints, opportunities and challenges in the lidar drone market. The Porter’s five forces analysis has been included in the report with a description of each of its forces and its respective impact on the market.

    Related Reports

    Lidar Market by Product (Aerial, Ground-based, and UAV LiDAR), Component, Application (Corridor Mapping, Engineering, Environment, ADAS, Urban Planning, Exploration, and Metrology), Services and Geography – Global Forecast to 2022

    UAV Drones Market by Type (Fixed Wing, Rotary Blade, Nano, Hybrid), Application (Law Enforcement, Precision Agriculture, Media and Entertainment, Retail), & Geography (Americas, Europe, APAC, RoW) – Analysis & Forecast to 2020

  • New engineering team at NovAtel to deliver safe positioning technology for autonomous vehicles

    New engineering team at NovAtel to deliver safe positioning technology for autonomous vehicles

    NovAtel Inc. announced a new initiative and engineering team to develop functionally safe GNSS positioning technology for fully autonomous applications. The company leverages its extensive experience developing safety-critical systems for the aviation industry to meet the future safety thresholds required for driverless cars and autonomous applications in agriculture, mining, and other government, military and commercial markets.

    In early 2015, NovAtel formed a specialized Safety Critical Systems Group of engineers with backgrounds in functional safety as well as all aspects of GNSS and inertial navigation systems (INS) technology. The Safety Critical Systems Group is focused on creating positioning products that will meet the exceptional performance and safety requirements of autonomous vehicles at the necessary production volumes and at the required price point.

    The company has extensive background working within safety critical requirements. Michael Ritter, president & CEO stated, “Aviation in North America relies on NovAtel technology to ensure safe navigation and landing.” Ritter added, “The Federal Aviation Administration’s WAAS, and other global Space Based Augmentation Systems (SBAS), have relied on certified NovAtel GNSS receivers for many years as the foundation of their systems. With full GNSS signal and constellation support needed to solve the performance criteria of autonomous driving, NovAtel is uniquely qualified to deliver the optimal solution that will keep us all safe as we drive the autonomous highways of the future.”

    Jonathan Auld, Novatel's director of Safety Critical Systems.
    Jonathan Auld, Novatel’s director of Safety Critical Systems.

    NovAtel manufactures high-precision GNSS receivers, antennas and subsystems, with expertise in sensor integration, specifically that of GNSS and INS. Through its TerraStar correction service, NovAtel also offers a global Precise Point Positioning (PPP) correction solution that is already designed for safety-of-life applications.

    With work underway for more than a year, NovAtel plans to achieve ISO/TS 16949 compliance by the end of 2016. This is an early key milestone in the Safety Critical Systems Group’s path, to be followed by an ISO 26262 compliant product.

    Jonathan Auld is director of Safety Critical Systems at NovAtel. He first joined the company in 2000 and has held positions as a GNSS test engineer, test group manager, director of technology development, and director of portfolio management.

  • Cobham displays antenna system at AUVSI’s Xponential 2016

    Cobham‘s Sunita Shah discusses the company’s AESA (actively electronically scanned array) antenna system at the Association for Unmanned Vehicle Systems International’s Xponential show, held May 2-5 in new Orleans.

  • Quanergy announces new lidar sensor at Xponential

    Quanergy Systems, a provider of lidar sensors and smart sensing solutions, is offering a new sensor.

    Quanergy's S3 lidar sensor
    Quanergy’s S3 lidar sensor

    The S3-Qi is a miniature solid-state lidar sensor that is 15 percent the size of the previous solid-state model, the S3. Quanergy is displaying the new sensor along with its other products in Booth 767 at AUVSI’s Xponential May 3-5 in New Orleans.

    The S3-Qi, offered four months after the original S3, has a smaller 1 inch by 1.5-inch footprint, weighs about 100 grams and has low power consumption. The small form factor, combined with a cost-effective design, makes the S3-Qi well suited for applications such as drones, intelligent robotics, security, smart homes and industrial automation.

    Mass production of the S3-Qi is targeted for the first quarter of 2017.

    “We are excited to raise the bar, once again, with the expansion of our product portfolio,” said Louay Eldada, Quanergy CEO. “We continue to push the boundaries on behalf of our customers. The S3-Qi is a testament to our focus on the user and our investment in innovation for game-changing smart sensing solutions offered at price points that make their use ubiquitous. In drones, payload and battery runtime benefit greatly from our compact sensors.”

    Quanergy’s lidar sensors have applications in more than 30 market verticals including security, transportation, terrestrial and aerial mapping, and industrial automation.

  • Sanborn mapping firm hits 150-year milestone

    A Sanborn fire insurance map of the Chicago Union Stockyards from 1890 (Image: Library of Congress)
    A Sanborn fire insurance map of the Chicago Union Stockyards from 1890 (Image: Library of Congress)

    Founded in 1866 to produce fire insurance maps, the current Sanborn Map Company offers high-tech mapping services that include mobile and aerial light detection and ranging (lidar), aerial oblique imagery and orthoimagery, 3D visualization, autonomous robotic indoor mapping, FAA-approved unmanned aircraft system (UAS) services and more.

    Sanborn made key contributions to America’s World War II effort, secretly housing classified Allied invasion maps critical to the D-Day invasion of Normandy in its historic Pelham, New York, building. That building is 110 years old this year, and Westchester County has declared April 20 as “Sanborn Map Building Day” to honor both the building and company anniversaries.

    Sanborn’s legendary fire insurance maps are distinctive because of their sophisticated set of symbols that precisely and clearly convey complex information. The Library of Congress Sanborn map collection includes 50,000 editions of the maps comprising an estimated 700,000 individual sheets dating back to 1867. The maps depict commercial, industrial and residential sections of 12,000 cities and towns across the U.S., Canada and Mexico.

    A sample of Sanborn's oblique imagery. (Photo: Sanborn)
    A sample of Sanborn’s oblique imagery. (Photo: Sanborn)

    Today, Sanborn has embraced modern geospatial technology, pioneering the collection and delivery of digital orthoimagery and collecting and processing high resolution oblique aerial imagery and designing derivative products.

    The firm has a vast oblique imagery collection. In 2015, Sanborn added 2.8 million new images to its Oblique Imagery Solutions database and provides proprietary tools, such as Sanborn Oblique Analyst software, so its customers can extract the maximum value from the imagery.

    Sanborn also offers 6-inch resolution orthoimagery covering the entire continental U.S. in both natural color and infrared products, and has one of the industry’s widest range of 3D, off-the-shelf mapping products. These include 3D Buildings, a suite of modeling products designed for 3D visualization and geographic information system (GIS) applications; 3D Cities for virtual city implementation; and CitySets, which comprise digital datasets covering the core downtown areas of most major U.S metropolitan areas.