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XTEND acquires Performance Rotors

Photo:

Image: XTEND

XTEND has acquired Performance Rotors, a Singapore-based UAV inspection company. This acquisition will improve XTEND’s ability to offer human-guided, remote interactive operations in a range of inspection scenarios.

“Performance Rotors’ mission has always been to develop UAVs and robotics solutions for data acquisition in GPS-denied and confined space environments, without the risk to human lives,” Keith Ng, co-founder and CEO of Performance Rotors, said. “We are confident that combining XTEND’s innovation XOS software with our world-class technology brings the best of the industry together in one powerful and easy to use solution that comprehensively addresses the critical challenges facing our customers today.”

XTEND provides human-guided autonomous machine systems that enable operators to perform accurate maneuvers and actions in any environment with minimal training. Its XOS operating system enables practical autonomy allowing professionals to control UAVs and smart machines that carry out complex tasks that require human interaction and decision-making safely and remotely.

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UK considering eLoran broadcast licenses

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The United Kingdom’s spectrum agency, Ofcom, is seeking comments on its proposal to issue licenses for broadcasting eLoran signals and services. This initiative comes, it says, after the agency was “…approached with a request to authorize use of the 90-110 kHz spectrum for the provision of a long-range navigation system, based on eLoran technology.” Issuing licenses could be a way to treat all interested parties fairly.

After briefly describing the importance of positioning, navigation, and timing (PNT) services to modern life, the Ofcom request for comment observes: “Satellite-based PNT systems like the Global Positioning System (GPS) can be susceptible to interference and can be vulnerable to space weather events. The eLoran technology provides a terrestrial-based alternative … which could in [the] future act as a supplementary or back-up system to GPS. [I]t has the potential to support innovation in the delivery of resilient PNT.”

This rationale is quite similar to that cited by other governments operating Loran-like systems around the world.

Until now, with a few minor exceptions, only government entities and those working on their behalf have been authorized to use the frequency. Such licenses would authorize holders to broadcast eLoran in the 90 kHz to 110 kHz band, which is the portion of spectrum reserved internationally for radio navigation.

From October 2014 to December 2015, the UK had an operational eLoran network serving the waters off its east coast and authorized for maritime use. That system was discontinued when France and Norway bowed to pressure from supporters of Europe’s Galileo system, which was still in development. The UK Ministry of Defence still broadcasts a single eLoran signal from Anthorn, UK, that can be used as a wireless timing source.

Several other nations currently broadcast some version of Loran in the 90 kHz to 110 kHz band. These include PNT systems operated by South Korea, Saudi Arabia, Russia and China. Reports indicate Iran is also broadcasting in the spectrum, though other details remain unclear.

Unconfirmed reports from amateur radio operators in the United States seem to indicate that testing of Loran-like signals in the 90 kHz to 11 0kHz band has been conducted in North America periodically over the last 10 years.

Until now, the UK has only formally authorized eLoran and the frequency for maritime use. Observers in the UK say this Ofcom initiative will almost certainly expand that to its use everywhere and for multiple applications, such as timing for critical infrastructure.

Ofcom says, “[d]eployment of eLoran in the UK could complement existing PNT services, particularly in locations where there is poor GPS coverage or weak signals, like tunnels or deep inside buildings. eLoran could also provide resilience (i.e., back-up) for satellite-based systems against interference, jamming and spoofing, thereby aiding protection of key national infrastructure…”

This Ofcom notice may be the first official move toward encouraging one or more entirely commercial eLoran services.

Commercial wide-area PNT services capable of protecting critical infrastructure and national economies have long faced an uphill battle, though.

Several industry leaders have commented that “it’s impossible to compete with free GNSS!”

The same leaders have also criticized the U.S. government for not “walking the talk” when it comes to resilient PNT. At a U.S. Department of Transportation meeting last year they urged the government to not just tell others, but to set an example and protect itself with resilient PNT services. Doing so, they said, would show industry and users the government is serious and instill confidence that commercial services were reliable and would be sustained.

Yet, experts cite a “chicken and egg” problem.

“The government can’t subscribe to services that don’t exist, and companies can’t stand up and provide nation-wide services without having an anchor-customer first,” according to an industry insider.

To solve this dilemma, public-private-partnerships have been proposed over the years in both the UK and the United States. To date, a willing “public” or government partner has yet to be identified for either nation.

This might be changing in the UK government with growing awareness about the limitations of and threats to GNSS and other space systems. While a national strategy for PNT has been promised for years and is yet to be published, a cross-government PNT office has recently been established.

“The UK is in a great position to lead the world on resilient PNT,” said one observer at a recent Royal Institute of Navigation event. “The key is working with GPS and other GNSS, while at the same time ensuring your nation has its own sovereign system independent of space. We (in the UK) have deep expertise and experience at the GLA (General Lighthouse Authority) with eLoran, and we have a superb tech economy. Britain could be the world’s leading producer of a resilient PNT tech stack that includes eLoran transmitters, receivers that use GNSS, eLoran, and other signals or phenomena, and all the supporting gear and IP (intellectual property) to make it all work.”

“Realizing that vision will take a bit more government leadership than just issuing a few broadcast licenses, though,” they said.

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SSC completes final delivery of second payload to Japan for hosting on QZSS

Space Systems Command (SSC) has successfully delivered the second and final spaceflight-ready payload to Japan, bolstering the contribution by the U.S. Space Force (USSF) to integrated deterrence in the region.

The two USSF payloads, developed by MIT Lincoln Laboratories, will be hosted on Japan’s GEO-based Quasi-Zenith Satellite System (QZSS). The deliveries of both payloads to Japan follows a Memorandum of Understanding signed between the two nations in December 2020.

This effort aims to demonstrate the ability of the U.S.-Japan alliance to extend to space; contribute toward the Department of Defense’s broader integrated deterrence posture against shared adversaries in the Indo-Pacific theatre; contribute to the USSF’s Space Domain Awareness; and provide a basis for future opportunities with international partners.

The hosted payloads will augment the USSF’s ability to conduct persistent, time-dominant volume search at geosynchronous orbit. Launch dates for the host satellites, QZS-6 and QZS-7, have not yet been announced.

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Unicore releases multi-application RTK module

Image: Unicore Communications

Image: Unicore Communications

Unicore Communications has released a GNSS, high precision, real-time kinematic (RTK) module, the UM960. This module can be used for a wide range of applications, such as robotic mowers, deformation monitoring, UAVs, handheld GIS, and more.

It features a high position fix rate and provides accurate and reliable GNSS positioning data. The UM960 module supports BDS B1I/B2I/B3I/B1c/B2a*, GPS L1/L2/L5, Galileo E1/E5b/E5a, GLONASS G1/G2, and QZSS L1/L2/L5. The module also has 1,408 channels.

In addition to its small size, the UM960 features low power consumption — less than 450 mW. The UM960 also supports single point positioning and RTK positioning data output at 20 Hz.

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Inside the box: GNSS antenna designs

sea level changes are monitored using a VeraChoke antenna at a GNSS observing station in Canada.

Sea level changes are monitored using a VeraChoke antenna at a GNSS observing station in Canada. (Image: Natural Resources Canada)

All antennas for global navigation satellite systems (GNSS) receivers serve the same fundamental function: to capture, filter, amplify the observed signals and relay them to the receiver. For high precision applications, certain design techniques allow for more accurate signal acquisition. These techniques involve the three main components of a GNSS antenna: the radiating element, additional ground plane, and the radio frequency (RF) frontend also called low noise amplifier (LNA).

Ceramic Patch Antennas

First, we will look at the antenna radiating element. Let us look at a common style of antenna that you might see in a surveying rover, a “patch” and associated ground plane. The patch, typically a metalized square or disk printed on a dielectric substrate, set in the middle of the ground plane, can have one or more feed points connecte to the RF frontend. For certain applications we may use only one feed point, which yields a narrow bandwidth; in other words, the circular polarization bandwidth of a single feed patch is very narrow. Single feed patches are then generally used for GPS L1-only applications. With two or more feed points, the circular polarization of the antenna is drastically improved over wider bandwidth. Putting it simply, for a two feed point antenna, the orthogonal currents flowing on the metalized surface of the patch are detected independently in both axes, one feed for each axis. The two signals are then combined using a 90 degrees hybrid coupler to reconstruct the GNSS information from the satellite. To cover multiple bands, such as L1 and L2, or L1 and L5, multiple patches can be stacked together.

Precision and Helicals

High performance dual feed patch antennas typically deliver phase information error of about 10 mm, though that does not mean you cannot achieve any higher. Depending on design specifics, other antenna technologies can achieve even higher precision. Helical antennas, another common design, yield a precision of at least 5 mm. They are taller than patch antennas, with a coil of four metallic elements pointing upwards. A key advantage is that helical antennas are less impacted by the absence of ground plane and still mitigate multipath interference in such a situation. Although being exceptionally light, a clear disadvantage of helical antennas is their height. However, a reduced height version of the technology is being developed that performs on par to the original technology.

Higher Accuracy

The key to even higher precision, down to an accuracy of less than 1 mm, is in the design of the individual components of the antenna element. Traditionally, the highest performing elements are quite sophisticated and difficult to manufacture, therefore they are quite expensive, and can be in limited supply. For certain legacy geodetic antennas, typically built into a choke ring, the element alone might cost several thousand dollars. We have taken inspiration from these designs and developed variations that have been able to deliver higher performance at a much lower cost.

Crossed Dipole Antennas

One of those approaches is an element that uses two wide band crossed dipoles mounted at 90 degrees from each other. The dipoles are connected directly to the RF frontend. Again, we combine two linearly polarized components through a 90 degrees phase coupler to reconstruct the right hand circular signal. Using RF engineering techniques these dipoles are coupled to other antenna element components, such as metalized “petals”, to improve or enhance performance in various ways. These enhancements include a wider bandwidth enabling the coverage of the entire GNSS spectrum, a more favorable radiation pattern; high low-elevation gain, and higher gain at zenith. This technology is the basis of our VeroStar, VeraPhase, and VeraChoke lines of antennas.

the rate of crustal motion is estimated using data collected by a VeraChoke antenna at a GNSS observing station at Rankin Inlet, Canada.

The rate of crustal motion is estimated using data collected by a VeraChoke antenna at a GNSS observing station at Rankin Inlet, Canada. (Image: Natural Resources Canada)

Ground plane and ChokeRings

Two additional elements that enhance certain antennas’ performance are ground planes and choke rings. An antenna does not necessarily need an external ground plane, a prime example being helical antennas. However, some antennas, such as patches, perform optimally with one. A choke ring is often used to attenuate signals from the horizon or below it, which are generally unwanted signals as they are typically due to multipath. To an extent, the concentric rings of a choke ring create a highly resistive surface for any low-elevation signals. Beyond the physical and electrical design aspects of the antenna, remaining interference from multipath may be mitigated algorithmically in the receiver.

RF Frontend

Coming after the radiating element is the RF frontend, another key component of high precision antennas. RF frontends include amplifier stages — which, as the name implies, amplify signals — and filters, such as ceramic or surface acoustic wave (SAW) filters, which reduce out-of-band signals while allowing in-band signals through. The GNSS signals from space are very weak and need to be amplified, often by a factor of 1,000 or more. There are two techniques for using filters: pre-filtering and in-line filtering. Pre-filters come before the first amplifier stage and prevent in band harmonics. In today’s congested RF spectrum, nearby signals or their harmonics can affect the RF frontend to the point that a non-prefiltered antenna will put the whole GNSS system at risk. A pre-filter mitigates this, but there is no free ride. Including a pre-filter in the RF frontend slightly increases the noise figure, which will slightly reduce the receiver signal-to-noise ratio (C/N0). However, a pre-filtered antenna will ensure the GNSS system to continue to operate in the presence of interference. Filters may also be applied between amplifier stages to further attenuate out-of-band interference.

In conclusion, a GNSS antenna is the optimal sum of three components: a well-designed radiating element, carefully selected external ground plane, and a high performing RF frontend. Technologies and models are available for every specific application that may arise. For example, patches are good general purpose antennas with a low-profile, helicals are lightweight and operate well without a ground plane, and crossed dipole antennas are ideal full GNSS rover and base station applications.

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WGIC announces executive board members and president for 2023-25

Image: WGIC

Image: WGIC

The World Geospatial Industry Council (WGIC) at its annual general meeting announced the members of its board who will serve from May 2023 to April 2025. The board is comprised of 20 senior geospatial industry professionals drawn from WGIC’s patron, corporate and associate member companies. The board will provide strategic guidance to WGIC in pursuing its mission and achieving its programmatic goals during the next two years.

WGIC Executive Board Members

  1. Theo Agelopoulos, Senior Director (Autodesk)
  2. Zubran Solaiman, Director (Bentley Systems)
  3. John Renard, President (Cyient)
  4. Bushra Zaman, Director (Deep Spatial)
  5. Elshan Musayev, EKM Global
  6. Dean Angelides, Corporate Director — international (Esri)
  7. Robert Hoddenbach, Global Director (Fugro)
  8. Jean-Francois Gauthier, Vice President (GHGSat)
  9. Adina Gillespie, Vice President (Hexagon)
  10. Steven Sawdon, Director (IIC Technologies)
  11. Paul Granito, Senior Vice President (Maxar Technologies)
  12. Harsh Govind, Principal Product Manager (Microsoft)
  13. Jayant Sharma, Senior Director (Oracle)
  14. Agnieszka Lukaszczyk, Vice President (Planet)
  15. James Van Rens, Senior Vice President (RIEGL International)
  16. Willy Govender, CEO (Terra Analytics)
  17. Marius Swanepoel, Director (TomTom)
  18. Bryn Fosburgh, Senior Vice President (Trimble)
  19. Joseph Seppi, Senior Vice President (Woolpert)
  20. Sanjay Kumar, CEO (Honorary Member) (Geospatial World)

The bi-annual election for the office of WGIC president has witnessed a unanimous vote for Bryn Fosburgh, Senior Vice President, Trimble. Brian Nicholls, Vice President — Asia Pacific, Woolpert, was elected unopposed as the treasurer. To ensure business continuity, John Renard, President, Cyient — Europe, will continue as secretary general till April 2024.

For more information, click here.

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TRX Systems awarded military contract for PNT device

Image: TRX Systems 

Image: TRX Systems

TRX Systems has been awarded a $402 million, seven-year contract by the U.S. Army for the procurement of dismounted assured positioning, navigation, and timing system generation II systems and services (DAPS GEN II).

The TRX Systems solution to be provided under the contract, TRX DAPS II, enables dismounted maneuver operations even where GPS is compromised or denied. TRX DAPS II provides assured positioning, navigation, and timing (PNT) to dismounted users by disseminating assured position and time to dependent devices in GPS-challenged environments.

TRX DAPS II fuses inputs from M-code GPS, inertial sensors, and complementary PNT sources. It is a small, lightweight PNT device that supports both standalone operation and integration with the Nett Warrior ensemble. It can also distribute PNT information to a customized tactical watch.

The TRX DAPS II solution employs a modular architecture and adheres to Army PNT interface standards, facilitating the addition of new PNT sensors as threats evolve.

TRX DAPS II will be in production for the Army later this year.

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Furuno to release multi-GNSS timing antenna

Image: Furuno

Image: Furuno

Furuno will release a high-performance multi-GNSS timing antenna, the AU-500, in July. The antenna is suitable for time synchronization applications.

The AU-500 supports all constellations in the L1 and L5 bands, including GPS, QZSS, GLONASS, Galileo, BeiDou, and NavIC. A built-in noise filter eliminates interference in the vicinity of 1.5 GHz caused by 4G/LTE mobile base stations as well as other radio waves that can adversely affect GNSS reception.

The antenna is equipped with lightening protection and features a high-quality polymer radome that prevents snow accumulation. It is also waterproof and dustproof in compliance with IP67.

The AU-500 achieves the best performance in time accuracy and robustness fundamental in critical infrastructure, when combined with Furuno’s GNSS receiver, GT-100.

In addition to the AU-500, Furuno will also launch the AU-300, an L1 single-band antenna with the same level of performance as AU-500, except L5 signal reception.

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Mapbox collaborates with Toyota and Lexus on in-vehicle navigation tech

Image: Mapbox

Image: Mapbox

Toyota and Lexus are now utilizing Mapbox‘s technology to deliver navigation features. Mapbox’s maps software development kit incorporates a map design that complements Toyota’s multimedia system, making turn-by-turn navigation intuitive for drivers.

With Mapbox’s navigation technology, Toyota can push updates to the design to vehicles in real time, so that the driver’s experience continues to be up to date. As more vehicles hit the road with the next-generation multimedia system, drivers of those vehicles will benefit from utilizing more engaging and robust navigation software that can be updated in a manner similar to updates on their smartphone.

Toyota’s designers are also able to modify the look and feel of the navigation experience via Mapbox Studio, enabling map design updates to be rolled out to all vehicles instantaneously.

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Spooky UAVs

Image: Jarvell Jardey/iStock/Getty Images Plus/ Getty Images

Image: Jarvell Jardey/iStock/Getty Images Plus/ Getty Images

This month’s column is an irresistible departure from sensible, autonomous UAVs and artificial intelligence (AI) news. We’re taking a small leap into who knows where.

How many of GPS World’s readers have interest in sci-fi, or at least are somewhat interested in the weird and wonderful stuff that shows up on some TV “reality” shows? Or maybe have a passing interest in the U.S. Navy’s Unidentified Aerial Phenomena Task Force, the U.S. Congress’s interest in unidentified flying objects (UFOs) and now the Airborne Object Identification and Management Synchronization Group (AOIMSG) of the Department of Defense (DOD)?

Yes, this a short meandering around what we now apparently call unidentified aerial phenomena (UAP), but mostly because one of those reality shows made use of UAVs in an effort to find out how or why UAPs may be concentrated in a particular location. That’s a location in northeastern Utah where Robert Bigelow may have previously spent millions of dollars of the Pentagon’s money conducting a study on UFOs. You may have heard of Bigelow Aerospace and their efforts to build inflatable orbital space stations. Bigelow was apparently intent on finding a logical answer to the UFO phenomenon and may have been involved for a while in the gathering of UFO sighting data on behalf of the Federal Aviation Administration (FAA).

The UFO/UAP flame has apparently been carried since around 2020 by a “scientific team” that puts out a regular TV program called “The Secret of Skinwalker Ranch,” which is broadcast on the History channel. There is a side of this program that also tries to deal with apparent paranormal “giant-red-eyed-wolf” activity at this location, but for today’s story, we are focusing on slightly more plausible, significant scientific efforts to identify UAP phenomena, not the less likely investigation of worm-holes at a site on the ranch (there goes all credibility, but please keep reading).

The cast of this show includes lead investigator, actor/scientist, Dr. Travis Taylor, who has two doctorates and three master’s degrees in engineering, physics and astronomy. He’s been involved with and has authored several articles in scientific journals, as well as nonfiction books and novels, appeared in TV presentations and worked for NASA and DOD on various programs.

The instruments of choice for this effort include forward-looking infra-red (FLIR), hand-held and UAV-mounted thermal and HD video cameras, wide-band frequency synthesizers and monitors, lidar scanners, and a data acquisition and display system that collects and analyzes all of the outputs of these systems, and GPS data. So, somewhat serious tech.

There are two areas on the ranch where UAP activity has been observed and has even been apparently stimulated by launching short-range rockets: a triangular intersection of three pathways or roads — referred to not surprisingly as the “Triangle” — and a field some distance off to the east, both at the foot of a mesa or flat-topped, raised area of land. As a side investigation, there were earlier efforts to determine what might lay buried inside the mesa, via video poked inside small caves, and then a horizontal drilling rig that apparently turned up exotic material similar to heat-shield re-entry coatings on spacecraft. This may be another diversion from the true search for UAPs, but then again maybe not.

Finally, some UAV involvement — a UAV aerial survey of the whole 512 acres of the Skinwalker site was carried out collecting data over a seven day period by VCTO Labs in Washington state with GPS RTK, acquiring the necessary 1 cm accuracy for a 3D model created by PIX4Dmatic processing.

About 32,000 images were captured and the resulting 3D model is now used as the geolocation truth model for the site. Nevertheless, surveying efforts over the last three years may have been hampered by the loss of three UAVs, thought to be due to some form of electromagnetic interference that brought them down.

When the team focused on the Triangle, there seemed to be one “anomaly” of some description at the center of the area at about 2,500 ft. So, to stimulate the anomaly or to create some sort of reaction, high density lasers were located at the corners and focused at about 2,500 ft. With these beams highlighting the suspect area, a large rocket was fired straight up toward the focus point. After a launchpad explosion that destroyed the first rocket, another was hustled into position, and launched successfully. At about 1,000 ft, the rocket was diverted some 30° off to the side, with no apparent high-level winds or other apparent influence, perhaps from some sort of guidance error.

As a follow-up and to gain more insight into another anomaly found flying a hand-held lidar in a helicopter at 300 ft above the triangle, it was decided to bring in a UAV lightshow by Sky Elements Drone Shows — an outfit based in Fort Worth, Texas, associated with SPH Engineering in Riga, Latvia. They run a heap of UAV shows in the United States and ran a recent 600-UAV show for the coronation in the United Kingdom and claim to have worked in 75 countries around the world. The object of the UAV show at Skinwalker was to see whether any “anomalies” would affect UAV guidance, and obviously many lighted UAVs in formation at altitude would make for good TV. The show uses a GPS RTK set-up, and the drones are guided by u-blox M8P GPS/GLONASS GNSS receivers.

So, with a rocket launched and the 1.6 GHz signal detected — it may have also been rebroadcast — the Sky Elements UAVs were powered up, lit up, lifted off and flown to altitude above the Triangle. All seemed well with all 200 lighted UAVs hovering in the night sky until a couple of UAVs “disconnected” — presumably from the 5 GHz Wi-Fi control channel, which has a secondary 915 MHz back-up. Then pandemonium erupted as the whole UAV display collapsed from the middle section, and the UAVs returned to the ground. To be sure, the 200 lighted UAVs were spun up again, flown up to altitude, and after a few minutes, the drop-out happened again as the fleet of UAVs returned to the ground.

The UAV show was moved to the notorious East Field and everything was repeated. However, other than what looked like a timing error as one UAV left early and was joined at altitude by the rest of the two hundred UAVs, no anomalies disturbed the formation.

The Skinwalker research team had instrumented the four corner UAVs of the display with a separate GPS receiver (and radio link?), so that their recorded position data could be used for subsequent analysis. Therefore, when the team huddled round the replay of the Triangle show in their control room, they had access to the UAVs’ location data from all the UAVs and the GPS location information from the four corners. Unfortunately (for our purposes) or fortunately (for the team), as the video/data analysis ran, a UAP was noticed flying over the proceedings. The image was clear enough for Travis Taylor to come up with a drawing of it, similar to a foreshortened dumb-bell.

Other than noting that the GPS altitude data for the UAVs that landed had been recorded as negative, or below the surface of the ground, the drone show analysis was put aside for extensive review of the UAP video — after all, the whole effort is prioritized to stimulate and analyze UAP anomalies, right?

So, what could we make of all this? Certainly, for me, the presence of the 1.6 GHz signal seems to be an indication that the UAVs’ GPS receivers and the GPS RTK reference receiver may have been jammed at L1. However, for the UAVs to return to their ground location, they may be programmed to do so when GPS guidance is lost.

So, why didn’t they behave the same at the East Field? Perhaps the jamming signal was localized at or near the Triangle? So, the next step would be to determine where this 1.6 GHZ signal originates. If it is re-broadcast by the team it might be a good idea not to do so. The u-blox M8P receiver includes GLONASS, but it doesn’t sound like there was associated RTK for GLONASS, so when GPS RTK was lost, GLONASS positioning alone may not have been able to meet the requirements of formation flight. So, the UAVs probably default to return-to-base logic, even though they may dead-recon back to the ground?

I asked my friends in Latvia whether they could confirm this layman’s hypothesis, but they needed the logs stored on the UAVs from those shows, and they were not apparently downloaded. It seems like there might be an opportunity for a re-run with post-show access to the individual UAV logs.

What about the analysis of the apparent UAP? Now, I must go watch more Skinwalker Ranch shows.