Tag: digital edition

High-powered satellites go beyond

Jackson Labs Technologies PNT-6200 Series, an STL-based time and frequency reference system installed in a 5G application. Photo: Satelles

We discussed Satellite Time and Location (STL) services and complementary PNT with Michael O’Connor, CEO at Satelles.

What is the problem with GPS/GNSS that Satelles aims to solve?

GPS and GNSS are amazing. We designed Satellite Time and Location (STL), the service that we offer, to complement those capabilities. We have focused on three unique aspects in the areas where GPS could use complementary service. First, we provide a fully independent backup. We all know that things can happen, so we aim to provide an independent source of position navigation, and timing (PNT). Second, we focused the high-power aspect of STL to enable us to reach indoors and other places where GPS does not reach. Because STL comes from low Earth orbit (LEO) satellites, the signals are naturally at a higher power.

We also focused on improving the indoor penetration capability by enhancing the signal design and doing some other things. Third, we use modern cryptographic techniques to ensure the security and resilience of the system, specifically to intentional misdirection attacks. If you can ensure that the signal is coming from the satellite and not from a third party you can have a more secure and resilient solution.

To what extent can you replace GPS during an extended outage?

We have never considered LEO PNT as a replacement for MEO (medium Earth orbit) GNSS. GNSS are the primary domain of PNT but there are applications that have additional needs. The more independence you can get, the fewer the common modes of failure, if you can at least have some survivability in the absence of GNSS. That’s one of the services we can offer. It is probably not the most important thing to our customers, honestly. The service we offer is similar to GPS and GNSS in that we have a space segment (the satellites), a ground segment, and a user segment. We have space vehicles, user equipment, and ground infrastructure that supports the space infrastructure.

What’s interesting about the way we work with the Iridium satellite constellation is that the satellites themselves include inter-satellite links. That provides a lot of resilience to ground-based events. The satellites themselves have a time transfer capability between them. So, we don’t require a direct connection to every satellite to propagate a time throughout the network. That’s one unique aspect we can take advantage of with this particular network, Iridium, which is pretty amazing.

Additionally, we have multiple ground infrastructure and monitoring sites and multiple sources of time at those ground monitoring and control stations. For example, some of them rely on GNSS combined with atomic clocks as their master timing source but we also have one installed at the National Institute of Standards and Technology facility in Boulder, Colorado. So, we have multiple primary time sources that we can integrate into our filtering across the network. That, combined, with satellite links, allows us to maintain time for substantial periods independent of GNSS.

How do you define “complementary PNT” and how does Satelles fit in that mix?

Several applications have additional needs beyond what GNSS offer. There are many technologies that can come to bear on that. There’s the LEO satellite base, which is where Satelles fits in, but there are also local and wide-area terrestrial radio navigation sources, network-based time transfer, signals of opportunity, and so on. They all have something important to offer, depending on the application. Satelles’ LEO satellite solution is available today, has global coverage, and is relatively affordable. It leverages the capital investments that have been made to launch the satellites to provide this service globally. The industry is working together to make sure that an awareness of these capabilities is propagated throughout the industries that we serve.

Besides the orbit height, which requires many more satellites, how does your system differ from GNSS?

We do not consider LEO PNT as something that might replace MEO PNT. The fundamental difference is being in lower Earth orbit, which results in a higher received power. That is what allows us to penetrate, just based on the 1/r2 losses. The measurable Doppler signatures give additional observables for PNT calculations, and higher satellite dynamics that can help with multipath. This service relies on many of the same physics and geometry as GPS. We measure the time of arrival of a very similar signal. The signals from the Iridium satellites are even in the L band. Very often we’re using a GPS chip that’s been reprogrammed to track and utilize our service as well as GPS or instead of GPS.

If I explained how GPS works to, say, a high school science class, how much of that basic explanation—about trilateration, spread spectrum, etc.—would also apply to your system?

It’s fundamentally the same. It relies on a lot of the same physics and geometry. We measure the time of arrival of a very similar signal. The signals from the Iridium satellites are even in the L band. Very often we’re using a GPS chip that’s been reprogrammed to track and utilize our service as well as GPS or instead of GPS. There are subtle differences—for example, a lower Earth orbit is faster—but it is very similar.

How would GPS user equipment have to be modified to make use of your service?

We don’t think of STL as something where we are modifying GPS user equipment. Rather, we think about what must be done in an end-user application to meet their needs. For example, one of our partners, Orolia, has a GNSS + STL secure synchronization product that we have delivered to customers in data centers and major stock exchanges around the world. Those are operational and in service. They integrate through standard interfaces, such as PPS or PTP, depending on the type of equipment to which they are connecting.
Ultimately, we don’t think of it is as replacing GPS user equipment. Rather, where a user has a need for PNT, they’re opting for this GNSS + STL solution because they have an indoor need, such as a data center, or they have a need for resilience in the case of a stock exchange.

Another example is Jackson Labs. The Jackson Labs 2600 is also a GNSS + STL solution that generally is integrating with existing 5g. It has a specialized transcoder interface that can work with any existing GNSS-type equipment. In some cases, we’ve taken a chip that was originally designed for GPS and modified its firmware.

Who are the earliest adopters?

Satelles’ LEO satellite solution is available today, has global coverage, and is relatively affordable. It leverages the capital investments that have been made to launch the satellites to provide this service globally. Data centers, stock exchanges and cell phone providers are implementing these capabilities today. The major wireless operators are seeing that more and more of the 5G infrastructure they roll out is going indoors, where GPS doesn’t reach. We provide a solution that integrates with their existing solutions and can provide reliable timing capabilities.

If your solution can survive on its own, why does it need GNSS at all?

In some cases, the user is not using GNSS at all. The product itself has a GNSS capability. User equipment is very affordable and the service is taxpayer-funded. In many cases, especially for indoor installations, the equipment that is installed is capable of tracking GNSS and STL signals, but often it relies on the STL signal itself for timing.

How do you predict STL spreading through various applications and industries?

We have our hands full with the markets we’re going after now, but there are certainly going to be other markets in which the customers will recognize that they have a critical need to implement a backup solution.

In the long run, could LEO satellites replace MEO ones for GNSS?

Sometimes there have been misperceptions in the industry. I’ve never considered that LEO PNT satellites might replace MEO ones. There are excellent reasons why Brad Parkinson, Jim Spilker, Gaylord Green and others decided almost 50 years ago to put GPS in MEO. Those physics haven’t changed. You can cover a large portion of Earth with each satellite. LEO will not replace MEO, but it has unique characteristics that make it a great complement to the GNSS MEO solutions.

Do you have any additional comments about complementary PNT?

It’s good to see that the federal government is encouraging the adoption of complementary PNT, which they often call “GPS backup.” It is encouraging to see the amount of activity on this issue that’s been going in Washington over the last couple of years. Although our company is very focused on delivering a LEO-based PNT service, which has several advantages for customers that need a global capability, many technologies can play an important role in those solutions.

The U.S. Department of Transportation did a fantastic job of looking at several of those technologies across those different categories. The European Union has also had a similar activity recently. Some reports will be coming out soon about that. It is very important that the government understands that this is an important issue for our society and encourages industry to adopt these solutions and is even starting to make some investments toward that. That includes executive order 13905 and some recent funding increases by Congress.

All of that has been very important and positive, as has modifying some of the legislation to be more inclusive of multiple technologies, such as removing the words “land-based” from the National Timing, Resilience, and Security Act this year.

I am involved in an industry consortium, the Open PNT Industry Alliance, with several other companies whose CEOs are in alignment that there is no single answer. Having a thriving ecosystem of technologies and companies trying to solve this important problem is incredibly important and it’s exciting to see.

July 11, 2022
New approaches improve PNT resilience

Data shows how successful baseline validation testing of Spirent’s inertial simulation model as compared to real world inertial system performance. Photo: Spirent Federal Systems

We discussed complementary PNT with Roger Hart, head of engineering and Jeff Martin, head of sales at Spirent Federal.

What are some of the most promising approaches to complementary PNT sources and how does simulation technology help?

Roger Hart: The vulnerabilities of GNSS have been recognized. Legacy GNSS are all operating on pretty much the same frequencies and power levels, so, they have some significant common vulnerabilities. There is great interest in finding ways to complement or even replace those capabilities.

Dead reckoning, magnetic and inertial systems have been around for a long time. There are emerging markets to make use of alternative radio frequencies for navigation. In some cases, we are piggybacking on communications signals and deriving PNT from them. In other cases, we are using new PNT signals. A couple that we’ve been focusing on are the alternative navigation systems.

They may be using different orbits, different frequencies, different encoding schemes that set them apart from the legacy GNSS systems, so that, used together, they provide greater resiliency and even stand alone when one or the other system may be affected by interference.

Not to be forgotten is inertial navigation. It’s been around for a long time and is still a standard of navigation. Together with GNSS, it makes it a terrific navigation system. It almost defines complementarity because where GPS is vulnerable inertial can fill in the gaps and where inertial drifts GPS does not. So, paired, they make a very strong system.

At Spirent, we’ve been working with customers to provide a variety of options for both those alternative navigation systems and inertial. Both are a very active field of development and we’re keeping abreast of that.

Jeff Martin: Some good points, Roger. This is something we’ve been engaged in for quite a long time. Since we provide test equipment to the community, it’s critical that we understand what they’re worried about, what the vulnerabilities are. It keeps things exciting, it keeps us on our toes and looking ahead to what’s coming.

What are some of the remaining challenges of integrating GNSS receivers with inertial sensors and, again, how does simulation technology help with that?

Hart: Inertial works by integrating sensor measurements that come in. Therefore, any errors that are present just accumulate over time and can corrupt your navigation solution. So, there’s a strong focus on updating error models and on translating them so that everyday users can use them and get real-life-type performance out of them.

There’s a tendency to think of integrating GPS-INS as putting everything together in one box. There are packages that do that. However, the push now is to go to more distributed systems that are integrated but not packaged in the same box. One example is the all-source positioning and navigation standard that is being developed by the Department of Defense. It will allow you to swap one sensor for another as long as they adhere to the standard. That information all goes back to a sensor fusion engine.

Martin: We have known GNSS simulators well for about four decades. We have been playing in the inertial sandbox for at least a couple of decades as well. This has given us the opportunity to build relationships with the with the key manufacturers and designers of inertial systems. Those relationships have been expanding well beyond inertial to many other sensors and systems that are now coming online. It’s been exciting.

Much work is going into using low Earth orbit satellites for PNT—whether piggybacking on the Iridium satellites or launching new ones. How does simulation help with that?

Hart: It certainly helps with the development of the receivers. The groups that are using these alternative RF and LEO or MEO systems need simulation as they develop the receivers. It gives you the ability to try things certainly before you launch them. At this conference there is considerable interest in making things reprogrammable. We have the NTS-3 satellite, which will be running experiments for different waveforms that can be generated. Even M-code is a step in the direction of giving more flexibility to the signal. It has a lot more flexible cryptography and signal generation than the legacy system with the C/A and P/Y codes.

Our simulation platforms are software based, so we can generate and receive data that can be useful for developing software-defined receivers. It gives you the opportunity to try different waveforms. We have already delivered a satellite-based alternative navigation system simulator. Now, we can build on that one to help the other Leo constellations as they come forward.

Martin: Roger put it well. This is where things get fun. People are concerned with PNT vulnerabilities, so we’re seeing these alternative navigation solutions coming forward. Spirent has done a good job over its nearly 40 years of existence of manufacturing and designing its own hardware and software. It has given us the opportunity to respond quickly. These things are coming fast. People need solutions quickly. We have some solutions already and the platform that we have created gives us the flexibility to develop more. We’re seeing more and more ideas come to fruition and people need to test them. So, this is where it gets fun. We’re excited.

Much work has gone into addressing the enduring challenge of urban canyons. How does simulation technology help?

Hart: Urban canyons are the worst nightmare for GNSS signals. If you’re surrounded by tall buildings, signals are blocked. You may have few or even no satellites in a direct line of sight and many multipath reflections. So, diminished and corrupted signals are available to you. Of course, the more GNSS satellites you have, the better chance you have of getting good signals. But complementing that are radar and vision systems. Those are the ones that will stand out, particularly the vision systems that can read the street signs, see where the curb is, look for parked cars. All those kinds of things will help fill in when you have poor GNSS coverage.

You can observe what’s going on in the environment and simulate it. You can also use our forecasting tool to look ahead.

Martin: This is where things get exciting, isn’t it? In these terrible environments where GNSS is contested—whether it’s an urban environment or one with intentional jamming—there is a lot we can do to help our industry. When this happens in real life, it’s bad news. But when you create that scary situation in the controlled environment of a laboratory, it is great. You can pick things apart and see where you need to improve. I get excited about it. It’s probably the geek in me. It gives us and our partners a lot to look forward to.

How does simulation technology help with sensor fusion?

Hart: It definitely helps you put all the pieces together. You can’t know how your system will work by individually testing each piece. System is the key word here. Simulation enables you to generate the signals and bring them together into a sensor fusion engine. You can test different algorithms. It’s certainly much cheaper and quicker than trying to build this into a product and then test it. Over the decades, simulation has proved itself as a very valuable way in both basic development and integrating the final product.

Martin: That system-wide fusion is where the magic happens.

It sounds like simulation technology—and Spirent Federal in particular—are very much at the center of a lot of the current developments and discussions about complementary PNT. Do you have any final comments?

Hart: As Jeff said, it’s an exciting time. There are many things going on—new technologies, new ways of communicating. It’s a busy time and a bit of a scramble sometimes to keep up with all the new things that are coming.

Martin: People look to Spirent to be their testing resource and it puts us right in the middle of it.

July 11, 2022
OxTS: Meeting accuracy demands

Mobile mapping using an OxTS xNAV650 INS and lidar sensor. Photo: OxTS

We discussed mobile mapping with Jacob Amacker, application engineer, OxTS.

How do you define “mobile mapping” as opposed to “surveying”?

We use the two terms interchangeably. Each one has a different connotation depending on where you are in the world and both can be useful. We use them to cover a broad range of use cases, but “mobile mapping” is used more specifically for land-based mapping of the environment. A typical application might be a van equipped with an INS [inertial navigation system] and lidar sensors.

“Surveying” can be used a bit more generally, applying to aerial or pedestrian-based mapping, but it does have the connotation of static mapping, which we do not typically handle.

What are your main markets for mobile mapping?

It is very hard to say. The world of mobile mapping is so diverse. However, lidar mapping could be seen as both the largest and the fastest-growing market in the surveying world as lidar has become widely affordable. Although our technology can be used with any surveying devices, at OxTS we particularly like to use lidar and are focusing on getting the best results from lidar data. This has included making our own point-cloud georeferencing software to maximize the potential of our navigation data in making point clouds.

What are the main differences between your devices for aerial mapping and for ground-based mapping?

We use the same INS device for both ground and aerial mapping. For use on manned aircraft, we would always recommend our highest accuracy system with the best IMU, the Survey+. The main source of inaccuracy in survey data will come from the IMU error over the range to the objects. Because most of this range is the aircraft’s altitude, this error is quite significant. For land-based mapping work, the measurements provided by the lighter and smaller xNAV650 are still suitable for many high-precision applications.

GNSS-INS integration has been done for decades. What is new and what are the remaining challenges?

It is now much more affordable to have very high-grade IMUs and GNSS receivers. Nevertheless, there will always be further improvements to be made to how the data streams are combined. On a similar note, other navigation aiding sources are increasingly being considered to supplement the IMU and the GNSS receiver — such as wheel speed sensors, lidar, camera odometry and others that can also be integrated to stabilize and improve the navigation data. Overall, it is very exciting what is yet to come out of INS technology. In recent years, it has become so good that people expect more and more from it, and this demand must be met. What happens when GNSS drops out? We are seeing increasing development to make the navigation data robust against challenges of any environment.

Given the IMU’s drift, for how long can your system function at an acceptable level in case of a GNSS outage?

It is difficult to put a number on what kind of drift is acceptable, as it depends on the application and the end-user requirements. Typically, half a meter of drift in one minute of GNSS-outage might be the goal for some of the higher-grade surveyors. Still others might only be satisfied with negligible drift.

What keeps the INS and the lidar unit synchronized during a GNSS outage?

The INS has an internal clock to keep the timing during a GNSS outage. Of course, this will not be as accurate as the atomic clocks on the satellites, but it is quite adequate to maintain survey-grade accuracy during GNSS outages. GNSS is still necessary to get the timing information in the first place, and this is a reliance that INS devices will want to remove in the future.

June 30, 2022
AEVEX Aerospace: Taming the Wild West

Lidar point clouds can reveal very fine features, such as electric power lines. Photo: AEVEX Aerospace

We discussed UAV lidar mapping with Bob Stadel, vice president of Geodetics, AEVEX Aerospace.

What are the key remaining technical challenges in UAV lidar mapping?

With continuing improvements in UAVs, lidars, GNSS receivers and other sensors, the key to unlocking more efficiency and profitability in this market will be improving and simplifying workflows and processing. The next frontier is integrating AI and machine learning with digital twin models to create forecasting tools.

UAVs are much cheaper to operate than manned aircraft per hour, but not necessarily per square mile. UAVs can cover ground that cannot be mapped from a land vehicle; however, the latter have a much greater range.

You are correct. Each type of vehicle has its area of best utilization. Once we know what the customer wants from the data being collected, we can determine the size, weight and power (SWAP) of the payload needed, and then it’s a matter of analyzing cost versus capability and working with the customer to pick the right payload for the right vehicle at the right price.

What positional accuracy do you achieve for your point clouds?

With our GNSS-receiver-based navigation unit, which also includes an IMU and key IP [intellectual property] from our company, and the right combination of tools, we achieve an accuracy of 2 cm to 3 cm.

What are your key markets for UAV lidar mapping?

I believe it is still the Wild West in this market space. Really smart people are figuring out new ways to use these systems every day. We sell systems to teams doing high-end inspections of infrastructure, such as roads, bridges, corridors and power lines, as well as for land surveying and mining.

What was a recent application of one of your mapping systems?

One of our most recent success stories has been the launch of our Geo-ECTO-1 system. It features dual lidar sensors combined with a 360-degree FOV [field of view] camera and high-end GNSS receiver. It is ruggedized from the ground up and is meant for high-end survey and infrastructure inspection work. The payload is designed to quickly transition to a UAV-based system. Our two launch customers/partners are California-based survey companies Guida Survey and LACO Survey. It has been a great experience getting these systems up and running with our partners.

Our next adventure will be to work with UC San Diego’s Scripps Oceanographic Institute. We are proposing and demonstrating one of these systems to be used for analyzing cliff erosion on the beaches here in California, where several collapses have led to the loss of life. We want to support figuring out how to use the analyses to create a system that would give early warning of trouble spots. With these tools we can make our beaches much safer.

June 30, 2022
Seen & Heard: Xona satellites, Russian bombs, better emergency response

“Seen & Heard” is a monthly feature of GPS World magazine, traveling the world to capture interesting and unusual news stories involving the GNSS/PNT industry.

Xona’s first demonstration mission successfully completed testing at Experior Laboratories and prepares for launch on a Falcon 9 in May. (Photo: Xona)

TAKING GNSS PRIVATE

At press time, Xona Space Systems’ first in-space demonstrator satellite, named Huginn, was ready to launch on May 25 aboard Space X’s Transporter 5 mission. Xona said the launch is a significant step toward realizing its high-performance commercial navigation system, a constellation of small, powerful satellites in low Earth orbit that will meet the navigation and timing needs of intelligent systems.

Photo: gorodenkoff/ iStock/Getty Images Plus/Getty Images

GEOLOCATED EMERGENCY CALLS

U.S. cellular carrier AT&T is rolling out location-based routing to automatically transmit wireless 9-1-1 calls to the appropriate call centers, rather than relying on which cell tower handles the call. Cell towers can cover a 10-mile radius, and overlap with more than one call-center boundary. With location-based routing, a device can be located and routed within 50 meters of the device location. The “Locate Before Route” feature from Intrado enables AT&T to use device GNSS and hybrid information to route the call to the right call center.

Russian fighter jets in better times. (Photo: Aterrassi/iStock/Getty Images Plus/Getty Images

RUSSIAN NAVIGATION CHALLENGES

Russian jets have been found using GPS receivers, while ground vehicles use paper maps, according to the UK Express. The GPS receivers were found taped to the dashboards of Russian SU-34s downed in Ukraine because of “the poor quality of their own systems,” UK Defense Secretary Ben Wallace said in a speech. With many reports of maintenance and aging issues for the Russian military, most likely the jets did not have quality GNSS receivers rather than the fault lying with GLONASS.

A Russian short-range ballistic missile, believed to be an unexploded Iskander missile, was found near Kramatorsk, Ukraine, in this photo released March 9 by Ukrainian authorities. (Photo: National Guard of Ukraine handout via Reuters)

UNEXPLODED BOMBS MAPPED

The HALO Trust is partnering with Esri to map unexploded ordnance in an immediate humanitarian response to the war in Ukraine. More than 10 million Ukrainians have been displaced by the war and many are forced to move across a landscape littered with unexploded rockets, bombs and landmines. In response, Esri has committed its cutting-edge geographic information system (GIS) software resources, expertise and staffing in support of HALO’s mission in Ukraine. HALO already is using GIS to map the heaviest conflict zones, and the partnership with HALO will support planning for future clearance operations.

June 29, 2022
Hexagon | NovAtel: Creating a digital world

Hexagon | NovAtel’s CPT7 integrates a GNSS receiver and an INS to deliver up to centimeter-level accuracy. (Photo: Hexagon | NovAtel)

We discussed mobile mapping with Bryan Leedham, product manager of enclosures and post-processing software, NovAtel, Autonomy & Positioning division, Hexagon.

How do you define mobile mapping?

It is getting broader in scope, as more folks find reasons to map the world. The key goal is to capture reality from mobile platforms to build a digital representation of reality for some large area, such as a city, a road or a factory. Most of the time, that means from a ground vehicle on public roads.

It’s also safer and faster than traditional surveying because you don’t have to stop traffic or dodge it.

Right! In an ideal world, rather than spending days setting up traditional survey equipment, you could strap some sensors on a mobile platform and gather accurate map data in minutes.

What are the key remaining technical challenges?

Picture one of Google’s or Waymo’s mapping vehicles. The first sensors that come to mind are GNSS, inertial, lidar and radar. Each of those has its own unique strengths and weaknesses. The first technical challenge that remains is to mature each of those technologies for a lower enough cost that it’s affordable.

Right now, mobile-mapping vehicles are quite expensive, especially in areas where some of these sensors will struggle more than others. To map very dense urban spaces — with underground areas, overpasses and tall buildings where GPS is challenged — you need a very strong localization system that can survive those conditions for however long it takes to drive through them. If I’m building a car to map rural Alberta, I could choose much cheaper sensors than if I were trying to map downtown Chicago every week.

On the flip side, you must deal with the massive amounts of data collected.

Yes, that is a very large challenge. Lidar data, in particular, is guilty of generating very large point clouds. It’s a balancing act. More accurate and higher resolution maps require lidar sensors with even denser point clouds. So, you need data management and sufficient processing power to get accurate results quickly.

What are the key technical challenges in sensor fusion?

Sensor fusion is how we approach the goal of mapping as accurately as possible in increasingly difficult environments. On their own, GNSS receivers struggle in obstructed areas but, when you pair them with other sensors, they become very complementary.

Lidar and cameras, for example, are quite good at measuring the distance to nearby objects and at classifying them, but they have no idea where they are relative to one another. Likewise, if you let an IMU [inertial measurement unit] sit in your car, it will no longer know its location. However, once you give it a position update, it is very good at maintaining a trajectory over a short period of time. When you combine absolute and relative localization, all the sensors play to their own strengths.

What is NovAtel’s SPAN software?

It stands for synchronous position, attitude and navigation. It is the sensor-fusion software that combines the GNSS, inertial and whatever other sensors. It is based on core NovAtel GNSS receiver software. We can use NovAtel receivers in combination with IMUs from a wide range of manufacturers and, in the future, hopefully, other sensors from a variety of manufacturers as well.

SPAN started with blending just GNSS and inertial but we’re now researching how to bring in such things as lidar and cameras. Autonomous Stuff, another Hexagon company, works on the greater sensor fusion using SPAN as well.

June 27, 2022
Applanix: NOAA’s eye for hurricanes

High-resolution imagery geolocated by the sixth-generation Digital Sensor System (DSS) after Hurricane Ida. (Photo: NOAA)

Applanix, a division of Trimble, has been working with the National Oceanographic and Atmospheric Administration (NOAA) since the early 2000s to develop their response for emergency and coastal mapping activities. We discussed this collaboration with Joe Hutton, the company’s director of inertial technology, land and airborne products.

How has Applanix collaborated with NOAA regarding emergency response and coastal mapping?

Early on, we worked with them to develop a solution that allowed them to get out in the field and produce high accuracy map products with minimal touching of the data. In mid-2021, we delivered the next generation of this solution, or the DSS version six, which represents the culmination of everything learned over the years about how to produce imagery for emergency response, in terms of the types of collection, the types of imagery, and how to get it into first responders’ hands as quickly as possible.

At the heart of the system is our direct georeferencing technology. It’s a solution that allows us to assign the geographic location of every pixel of the digital imagery collected in the air. As soon as you land, you have the coordinates of every pixel, which means that you have a map that NOAA then pushes to the cloud for first responders to use in their emergency response efforts.

The collaboration consisted of Applanix working with Lead’Air to manufacture the next generation system that meets NOAA’s latest requirements. That’s what we delivered in 2021. Weeks after delivery, NOAA was called to respond to the hurricanes. They flew the new system with great success and were able to use it for their response.

What is your perspective on ground control points (GCPs) vs. direct georeferencing?

It is impossible to place GCPs in an emergency response when you cannot get on the ground. People who say they need GCPs do not really understand direct georeferencing. We’re having this debate even after 20 years of proving this technology. The NOAA system does not use GCPs and the map products are at centimeter level accuracy.

We use Trimble’s RTX technology, which enables centimeter-level GNSS positioning without base stations, which is important when the CORS or local RTN is unreliable due to a disaster. We have high accuracy inertial systems that get us the high accuracy orientation, so that we can go directly to ortho photos and ortho mosaics without running any triangulation or using GCPs in that process. That is a standard process these days. GCPs are only there for quality control if you want to deliver a final map product.

Did NOAA fly the mission with its own aircraft?

Yes, these are NOAA’s King Air or Twin Otter aircraft. The King Air aircraft is specifically outfitted for these types of emergency response and coastal mapping activities. The DSS system gets installed into the airplane and gets calibrated in terms of checking the system out for accuracy. Then it’s ready to fly the response. In the air, they collect the imagery over a flight path of interest to them. Then, it’s developed from raw imagery into JPEGs in the aircraft, and all the georeferencing data is logged with that imagery so that as soon as they land they can push a button and start to reference the JPEG imagery and push it to the cloud.

What are the components of your system?

What makes this system so unique is that it encompasses all the lessons learned over the years in terms of what NOAA needs to optimize for both their coastal mapping and their emergency response. It incorporates two pairs of color and near-infrared Phase One cameras that are configured in an oblique format with some overlap, forming a bowtie footprint on the ground.

You have 100% overlap of the color with the near-infrared and it’s on a high-performance stabilized mount that keeps everything perfectly level. The mount also has a special feature that enables the operators to rotate the cameras to go into nadir mode, mostly for traditional coastal mapping that requires stereo imagery. We were able to incorporate into a single system the requirements for both emergency response—where you want large coverage and obliqueness to look for damage—and nadir for coastal mapping.

Lead’Air built the sensor for you, on your specs, correct?

Yes, that’s correct. We’ve worked with Lead’Air for probably 20 years on flight management system (FMS) technology. They also have an amazing capability to build stabilized mounts and hardware systems. So, we decided to work together. We contracted them to implement some of their innovative hardware in this new design for us to deliver to NOAA. We contracted them to do all the manufacturing of the design and delivery to NOAA.

One of the quite innovative things that they did was to develop a new flight management capability that allows NOAA to fly ad hoc along highways or rivers, looking for damage. Traditionally, for aerial imagery you have to pre-flight plan trajectories. They designed an FMS that enables a pilot to fly a road or a river looking for damage without worrying about traditional block collections as with a more traditional FMS. So that feature further increases productivity. If you look at the most recent imagery at www.storms.ngs.noaa.gov you will see that it looks like spaghetti, not like blocks. That’s because they are following the roads and the rivers looking for specific damage.

Does the post-processing use your software?

Yes, it uses the POSPac MMS post processing software with POSPac Trimble Post-processed CenterPoint RTX correction service, allowing us to get that centimeter-level position accuracy, anywhere in the world with just an internet connection. You don’t have to worry about having a local base station—which, of course, if you’re in an emergency response situation, might not be there anyway. So, this is a very powerful way of getting global centimeter-level accuracy in real time, without having to worry about the ground-based GNSS infrastructure, that is, the local real-time network, that’s on the ground.

If you don’t have internet access, you can ship that data to the nearest place that does, right?

You could, however NOAA simply flies to wherever there is access. What takes the longest is to develop the imagery from the raw format to the JPEG format, because these are such large images. Doing that in the air saves an enormous amount of time. You have these JPEG-ready images that are compressed and can go right into the georeferencing process and make it really, really fast.

That’s a matter of computing power and smart software. What else did Lead’Air contribute?

This very efficient, fast image development process in the aircraft.

It sounds like it was a very integrated process between Applanix and Lead’Air. So, NOAA had the instrument mounted on their aircraft, their pilots did the flying, and then you processed the data?

No, NOAA’s team processes all the data. We just deliver the hardware and the software. They created the workflow software to push the data to their cloud environment.

NOAA uses this data to produce maps of the damage and highlight different situations and hazards?

Yeah. When these hurricanes go through, the first questions people have are “Where’s the damage? Are these roads passable? Did my house survive?” If you are doing response, you need to get teams in there. First, however, you need to know whether the roads are passable, so that you will not waste time going down a road that is not. So, the first thing they do is go up in the air and survey the main roads to push the imagery back, so that people can assess whether the roads are passable. Then they start to look for specific areas of damaged infrastructure, to triage where to put their resources. Then they ask “How do we manage disaster recovery?”

What lessons did you learn?

We are still learning about the power of the system, because these are Phase One 150 megapixel color cameras. It is such a powerful combination of sensors that they’re starting to look at different information they can get out of these things. They’re still learning new lessons in terms of what information can be useful for both the emergency response and the coastal mapping.

Ultimately, we’ll go to full ortho maps in the aircraft. That’s just going to be a matter of computational power. The holy grail would be to produce an orthophoto in the aircraft and radio it down to the ground in real time. Nothing prevents you from doing that now other than computational power and bandwidth. It’s not practical yet, but it will probably get there.

Do you have collaborations like the one with NOAA with any other major U.S. agencies?

We’ve worked extensively with NASA over the years. For example, we have worked with them on the ice bridge project. That is where they survey ice at both poles to measure its thickness and how global warming is affecting it. They use our system on that to do the georeferencing. We also work extensively with other branches of NOAA for their shoreline mapping from their ships. We have worked with them over the years to provide the georeferencing solution for the multibeam echo sounders to produce their nautical charts.

June 27, 2022
Advancing the A in PTA

Matteo Luccio

The May 4-5 meeting of the National Space-Based Positioning, Navigation and Timing Advisory Board focused on its mantra to “protect, toughen and augment” (PTA) GPS. The meeting included three great presentations that bear directly on the A of that mantra.

CAST

The electric grid used to be simpler: regional operators flowed power unidirectionally from stations to customers basing the load on past usage. Now, the grid is becoming a wide-area network — with regional inter-connects, multi-directional flows, and load based on real-time data and predictive analysis, requiring sensors time-synchronized within 1 microsecond from UTC. Yet, this critical infrastructure’s timing applications depend entirely on vulnerable GPS technology.

“If we can provide an authoritative, trusted synchronization source across the interconnected grid, its operators have a much better opportunity to understand the interdependencies and movement of power across their networks,” said Carter Christopher of Oak Ridge National Laboratory. He described the lab’s Center for Alternate Synchronization and Timing (CAST), which provides a redundant and resilient satellite-based service backed up by a network of terrestrial master clocks. CAST is precise, traceable and secure from jamming, spoofing, cyberattacks and physical attacks.

HARS

Attila Komjathy and Larry Romans of NASA’s Jet Propulsion Laboratory (JPL) proposed a GPS high-accuracy and resilience service (HARS) based on global differential GPS (GDGPS). It would provide corrections to GPS orbit and clock errors, and encrypted navigation data bits over the internet. It would match Galileo in accuracy, they said, pointing out that Galileo, QZSS and BeiDou provide high-accuracy services in their broadcast signals. HARS would improve the accuracy of consumer GPS receivers of 3–5 m to 1 m and help ensure that multi-constellation GNSS chips would continue to rely on GPS first.

HARS could be implemented by having commercial providers—such as Apple, Google and cellular carriers—distribute GDGPS corrections generated by JPL and supported by government partners. Private industry, Komjathy and Romans pointed out, provide service for RTK, centimeter and decimeter apps, but only governments (the U.S. Coast Guard’s DGPS service and Galileo’s HAS) provide corrections for about one-meter accuracy. Therefore, HARS would not compete with industry and would create additional opportunities for it to create value-added products.

αPNT

David Castiel and Cyrus Langroudi, of Virtual Geosatellite LLC, proposed αPNT, a virtual geostationary satellite system with elliptical orbits that would provide active PNT in a distributed architecture integrated with a blockchain. The system, they said, would be able to provide very accurate geographical position, precise timing and guidance with a minimum number of satellites on the horizon. It would rely on two-way links between transceivers and satellites to protect against jamming or spoofing.

While GPS’s success makes it a critical and ubiquitous infrastructure, its vulnerabilities require and stimulate exciting new R&D. Stay tuned.

June 27, 2022
Launchpad: Mobile mapping, surveillance system, airborne lidar

A roundup of recent products in the GNSS and inertial positioning industry from the June 2022 issue of GPS World magazine.

SURVEYING & MAPPING

Base/Rover

For survey-grade GNSS accuracy anywhere

Photo: Bad Elf

A base/rover feature built upon the Flex GNSS receiver brings affordable centimeter-level accuracy to surveyors and geospatial professionals working anywhere in the world. The solution consists of two Flex GNSS receivers and two UHF radios, allowing customers to perform high-accuracy field data collection in areas where traditional real-time kinematic (RTK) corrections or cellular coverage is not available. Existing Flex customers can upgrade by adding Flex radio kits (pictured). The Bad Elf Flex enables data collection either as a standalone receiver or paired with apps on iOS or Android phones and tablets.

Bad Elf, bad-elf.com

Mobile Mapper

Preserves privacy with artificial intelligence

Photo: Leica Geosystems

The Leica Pegasus TRK reality-capture mobile-mapping system features artificial intelligence (AI), autonomous workflows and intuitive interfaces. To comply with privacy regulations, its AI can identify and blur identifiers, such as people and vehicles, in real time. Features include advanced dynamic laser scanning and an expandable imagery system for recording, measuring and visualizing. It enables long-range mobile mapping for asset management, road construction, rail, critical infrastructure, utilities and more. The system also can create high-definition basemaps for autonomous vehicles.

Leica Geosystems, leica-geosystems.com

Imaging System

Delivers colorized products with high accuracy

Photo: GeoCue

The True View 645/650 is the latest 3D Imaging System (3DIS) from GeoCue. Combined with the True View EVO data-processing software suite, it includes the full post-processing software workflow and directly integrates with Applanix POSPac. EVO supports the creation of project deliverables including ground classified point clouds, surface models, contours, digital elevation models (DEMs), volumetric analysis and wire extraction. The system delivers colorized lidar deliverables with accuracy better than 3 cm root-mean-square-error (RMSE) for the True View 645, and better than 2 cm for the True View 650.

GeoCue, geocue.com

OEM

Front-End Receiver

Software-defined receiver front-end

Photo: IP-Solutions

The Eagle-2 works with software-defined receivers in real time or records GNSS signals for post-processing. For post-processing, Eagle-2 supports most third-party receivers, such as MATLAB and C/C++ receivers. The front end allows a user to work with two perfectly synchronized channels connected to two antennas. The Eagle-2 supports GPS, Galileo, GLONASS , BeiDou, QZSS and SBAS.

IP-Solutions, www.ip-solutions.jp

Helical Antennas

Feature extended filtering of interference

Photo: Tallysman

The housed HC885XF and embedded HC885EXF dual-band eXtended Filtering (XF) antennas receive GPS/QZSS L1/L5, GLONASS G1/G3, Galileo E1/ E5a/b, BeiDou B1/B2/B2a and L-band corrections services. They have been tuned to provide optimal support for the entire L1/G1/E1/B1/L-band correction and L5/G3/E5/B2 bands. The housed version, HC885XF, weighs ~42 g and is enclosed in a robust, military-grade IP67 plastic enclosure. The embedded version, HC885EXF, weighs ~8 g and is easily mounted with an embedded helical mounting ring.

Tallysman Wireless, tallysman.com

Converter

Sets performance benchmarks for harsh environments

Photo: Analog Devices

The AD9213S-CSH is a highly integrated RF analog-to-digital converter that handles 12-bit, 10.25-giga-samples per second. It is the company’s fastest ADC available for the space environment. The AD9213-CSH enables the next generation of software-defined systems for satellite communications, radar and remote sensing. The high sample rate and integrated post-processing enable further performance gains for narrow-band applications.

Analog Devices, www.analog.com

UAV

Ebook

Provides guidance to achieve corporate buy-in

Photo: Skyward

Skyward has published a free ebook, Adding Drones to the Enterprise, to provide guidance on establishing a corporate drone program. According to Skyward, the most efficient and effective drone programs are the lowest risk and most compliant. Topics covered include how to present the business value of a drone operation to corporate executives; how risk managers can optimize the workflow to ensure maximum safety; best practices for risk mitigation and regulatory compliance; tips for collaborating with legal and compliance teams on a general operating manual; and how to provide full transparency to corporate stakeholders.

Skyward, https://go.skyward.io/adding-drones-to-the-enterprise-ebook.html

Enterprise System

Includes drone, fleet software and charging dock

Photo: DJI

DJI’s all-in-one solution for professional drone operators includes the DJI Matrice 30 (M30) drone integrated with DJI FlightHub 2 fleet-management cloud software and DJI Dock for autonomous docking and recharging. The integrated solution is suitable for Enterprise drone users such as public safety agencies, infrastructure inspectors and energy operators. The M30 model is designed for rugged professional uses, while the fact that it fits in a backpack makes transportation and setup fast. The DJI Dock is an autonomous takeoff, landing and charging station allowing fully automatic, programmed flights with the DJI M30 Series (Dock Version). After setup, the fully charged M30 drone can take off from the dock through FlightHub 2 programmed automatic missions anywhere within a seven-kilometer radius.

DJI, www.dji.com

Airborne Lidar

Easily installed on various UAV platforms

Photo: CHC Navigation

The AlphaAir 1400 (AA1400) and AlphaAir 2400 (AA2400) lidar systems are lightweight, compact airborne scanners easily installed on various UAV platforms or small survey aircraft and helicopters. They are adapted to high-density point-corridor mapping applications, day or night, under leaf-on and leaf-off conditions or with dense vegetation to provide reliable results. Combined with industrial-grade GNSS receivers and high-precision inertial measurement units (IMUs), the AA1400 and AA2400 provide 2 cm to 5 cm survey-grade accuracy. They also integrate Riegl VUX lidars with waveform-lidar technology, allowing echo digitization and online waveform processing.

CHC Navigation, chcnav.com

Autopilot

Provides built-in redundancies

Photo: UAV Navigation

The VECTOR-600 is a robust, dependable autopilot with built-in physical and logical redundancy, allowing it to survive all individual sensor failures while maintaining accurate estimates of attitude and position. It works for fixed-wing, rotary-wing and vertical-take-off-and-landing UAVs. It provides exceptional performance in GNSS-denied environments and when there is a jamming threat. The VECTOR-600 features high quality components and an electromagnetic-resistant design tested to MIL-STD 461.

UAV Navigation, uavnavigation.com

Surveillance System

Ground-based solution enables safe operations

Photo: Iris Automation

Casia G is a ground-based detect-and-avoid surveillance solution that provides 360° optical detection with alerts. It enables operators to avoid both cooperative and non-cooperative aircraft for safe beyond-visual-line-of-sight (BVLOS) flight. Casia G creates a perimeter of monitored airspace for UAVs to perform work safely, without additional payload. It is suitable for operations in fixed or temporary locations, supporting drone-in-the-box operations and augmenting or replacing human visual observers. Casia G sees the entire sky, with uniform probability and resolution, 10 times per second, covering a majority of small UAS use cases.

Iris Automation, irisonboard.com

June 16, 2022
Editorial Advisory Board Q&A: The need for correction services

Will GPS modernization and improvements in GPS receivers and antennas reduce or even eliminate the need for correction services for most applications?

Julian Thomas, managing director, Racelogic

“For most applications, I think the answer is yes, the need for correction services will be reduced. When you can get <1m without external corrections, the majority of conventional accuracy requirements are fulfilled. However, increases in accuracy always open up new applications for GPS, so correction services will still be required.”
— Julian Thomas
Racelogic

Miguel Amor, chief marketing officer, Hexagon’s Autonomy & Positioning Division

“Correction services will continue to be in demand for those markets and applications requiring precision and accuracy below a few inches, 2-3 sigma confidence levels and high reliability, availability and integrity. While ionospheric errors have been low in the past 15+ years, correction services will also provide ionospheric models beneficial in periods of higher activity. Even as there are improvements in user equipment and signal modernization, the demand for correction services will increase in line with these improvements and new functionalities to enable more markets and applications worldwide.”
— Miguel Amor
Hexagon’s Autonomy & Positioning Division

June 14, 2022
Magnetic Navigation 2022 – Freedom from GNSS?

Dana Goward, President, Resilient PNT Foundation

In a world where GPS and other GNSS signals can be easily denied or, worse, spoofed, interest in other forms of navigation has rebounded.

Imagine being able to locate yourself within a couple of centimeters with just your cellphone – deep underground. Or inside a metal structure. Or underwater (assuming you can keep your equipment dry).

No satellite signals, no Wi-Fi ranging, no inertial system. Just the ambient magnetic flux that constantly surrounds us all. Everywhere.

That’s the vision AstraNav Vice President Martin Neill offered to the President’s National Space-based, Positioning, Navigation, and Timing Advisory Board in May.

Animals have used the Earth’s magnetic field to find their way for millions of years. People have been using magnetic compasses for over a thousand. Until the advent of GPS, magnetic compasses were foundational tools for aircraft and ship navigation, especially when out of sight of easily recognized landmarks.

Then GPS came along, and almost everyone’s eyes turned to space.

But in a world where GPS and other GNSS signals can be easily denied or, worse, spoofed, interest in other forms of navigation has rebounded. And because GPS helped demonstrate the efficiencies geospatial services provide, users also want those services to be more resilient and to work in places signals from space just can’t reach.

According to Neill, “Our solution builds upon inexpensive magnetometers, smartphones, machine learning, edge computing, and some incredibly complex math to convert raw magnetic data into a source of ultra-precise location data. These relatively recent tech developments allow us to bring things together for a major update to a centuries-old way of navigation and positioning.”

Describing AstraNav as a software tech company, Neill said that the company’s system is “hardware agnostic.” It can work on “just about anything that has a magnetometer. No additional hardware or external connectivity is required, and we can run on any existing operating system.”

Image: Credit: Petrovich9/iStock/Getty Images Plus/Getty Images

The company has partners in retail, automotive and telecom validating the technology. They have also been working with a U.S. Department of Defense (DOD) combatant commander to demonstrate the product, as well as Virginia Tech and its National Security Institute (VTNSI.) “This is not a case of ‘here’s an idea that we hope will materialize,” said Neill. Describing two real-world trials and use cases to the board, he said, “This technology is a reality, and we’re doing it.”

Most previous magnetic navigation efforts relied upon relatively low-resolution maps. An airplane could find its way safely across the ocean using the maps that were available and likely end up within a mile or two of an airport. Much higher resolution maps built through surveys and artificial intelligence are critical to AstraNav’s centimeter-level accuracy with systems that continue to learn on their own.

Intellectual property is AstraNav’s biggest asset. “We have multiple patents filed and pending,” said Neill. “Our IP is what allows us to sense and analyze magnetic fields so finely, develop maps, and make use of very low-cost magnetometers, such as the ones in cell phones.”

Several people at the advisory board presentation expressed surprise that they had not heard of the company and this capability before. “We have been busy getting established as a company, supporting our first commercial clients, and doing demonstrations for various folks within DOD,” Neill explained. “This presentation is by way of our coming out party. We are very eager to become better known and are looking forward to explaining our capabilities one-on-one with potential users.”

Citing an abundance of proprietary material, Neill was unwilling to discuss a lot of technical detail at the public meeting. His short presentation, he said, was to raise awareness and stimulate interest.

The number of those in attendance who after the presentation said they were eager to learn more showed that he was successful.

Dana A. Goward is President of the Resilient Navigation and Timing Foundation

June 9, 2022
Surveying the innovation of GPSIA members

Alex Damato

In the decades since the U.S. GPS became fully operational, GPS has become a highly innovative, successful and increasingly ubiquitous technology critical to applications and services touching the lives of almost every American today and for decades to come. As GPS-enabled technologies have become an irreplaceable part of our national infrastructure, growing more deeply ingrained each year, GPS is a success story of what can happen when government-backed R&D, paired with a light-touch regulatory approach, is turned loose in the private sector.

At the GPS Innovation Alliance (GPSIA), our member companies and affiliates are driving this innovation forward. While we use their products every day now, they’re also focused on inventing the future. Several key features are necessary to this continued success: a stable and predictable spectrum environment; a regulatory framework that fosters innovation and balances the fundamental technical needs of navigation systems; and appropriate, established interference protections where necessary.

Regulators must take care not to fundamentally depart from the longstanding approach to spectrum policy that has enabled the GPS technologies and services that underpin our economy. The prize on the other side of a well-calibrated policy is the next generation of GPS-enabled applications and products, which, as a GPS enthusiast first and foremost, I get a front row seat to our members building every day. These innovations span land, sea and space, unlocking opportunity for their U.S. government partners and consumers alike.

Innovations on Land, at Sea and in Space

On Earth, GPS-based products and services are getting even better at improving our everyday lives, helping farmers, builders, drivers and hobbyists work more efficiently and providing the critical inputs for everything from trucks to cell phones.

Take GPSIA member Trimble’s recently introduced R750 modular GNSS receiver, a connected base station used in both civil construction and agriculture that provides improved base-station performance and gives contractors, surveyors and farmers more reliable and precise positioning in the field. John Deere is likewise helping build next-generation precision agriculture technology with its new autonomous tractors, which will use GPS signals to ensure optimal plowing, planting and harvesting by adapting to real-time data analytics on soil conditions and other factors.

Garmin, a household name in GPS consumer products, continues to enhance satellite location and communication technologies for increased safety and user awareness, recently launching its inReach Mini 2 compact device that offers up to 30 days of battery life, integrated location and situational awareness technologies, and two-way texting and SOS capabilities.

Elsewhere, CalAmp recently celebrated two years of partnership between their LoJack Stolen Vehicle Recovery System and BMW Group Italy, the first step in a larger plan toward a GPS-based security solution for BMW’s full product range, while Apple continues to build revolutionary consumer tech, such as their GPS-enabled Apple Watch that can track workouts, activity, elevation and time, all without connection to an actual iPhone.

The ubiquity of GPS is particularly critical at sea. Collins Aerospace, for example, just launched Artemis Elite, the first–ever military underwater navigation system (MUNS) with M-code  technology, that improves GPS signals’ precise positioning, navigation and timing (PNT) capabilities, making them more resistant to threats of jamming and spoofing. Garmin is also improving the consumer boating experience with its suite of OnDeck products, which pair onboard sensors and GPS to create a remote monitoring and management solution giving boaters 24/7 access to critical and timely information about their vessels.

Of course, GPSIA members are driving the effort to modernize the GPS satellite constellation itself. Lockheed Martin is building the next generation GPS III satellites and follow-on GPS IIIF satellites that will improve antijamming capabilities and geolocation accuracy for GPS-enabled devices, while L3Harris is building critical inputs on these satellites, such as their advanced navigation and timing payloads.

Our companies are also leading the way to help nations operate in space, providing critical GPS applications including guidance systems for crewed vehicles; the management, tracking, and control of communication satellite constellations; and monitoring the Earth from space.

Raytheon, for example, announced this month that it installed the first global aircrew strategic network terminal (ASNT) for the U.S. Air Force to enable protected communication capabilities for aircrews, while Lockheed Martin is the primary contractor in a cutting-edge project from the Space Development Agency to improve U.S. missile tracking and defense through a layer of multi-orbit satellites speaking to one another and sharing location data in real time.

Looking across GPSIA’s member companies, it’s clear that we live on a globe propelled by GPS. We should continue to give them the tools — and protect the regulatory framework — that has allowed them to do what they do best, which is bring us products that transform our daily lives for the better and innovate new technologies and services.

June 6, 2022