The Global Positioning System (GPS) project started 50 years ago, in 1973. I was fortunate to be part of incorporating GPS into the National Spatial Reference System (NSRS) when I worked for the National Geodetic Survey (NGS). GPS was not considered operational until 1993, but NGS started performing GPS surveys in 1983. Geodetic control surveys that formerly took six to 12 months to perform using classical methods could be performed with GPS in a few weeks using fewer personnel and resources. It changed the way NGS and others performed their surveying operations.

While one group in NGS was developing programs to evaluate and compute coordinates using GPS, another NGS group was completing the readjustment of the North American Datum of 1983 [NAD83 (1986)]. The analysis of GPS indicated that some of the latitude and longitude values estimated using GPS did not agree with the published NAD83 coordinates. The classical techniques used a triangulateration process (involving angles and distances) that required several triangles to connect two stations that were not intervisible. GPS, on the other hand, could directly measure the distance between the two stations, resulting in more accurate coordinate differences.

To support surveyors, NGS, working with other federal agencies under the auspices of the Federal Geodetic Control Subcommittee (FGCS), developed a GPS test network in the Washington, D.C., area to demonstrate whether a specific manufacturer’s GPS receiver and associated geodetic post-processing software was an accurate relative positioning satellite survey system. This facilitated the use of GPS for incorporating geodetic control in the NSRS. As mentioned above, GPS surveys exposed many inconsistencies between existing NAD83 (1986) control. Organizations such as NGS and state transportation departments that performed control surveys used GPS as soon as equipment met the federal testing requirements because it was more efficient and cost-effective than classical techniques. This led individual states to perform statewide geodetic network projects to upgrade their NAD 83 (1986) coordinates. These surveys were ultimately designated as High Accuracy Reference Networks (HARN).

In the beginning, the attitude of the individual surveyor accepting GPS was one of “trust after verifying.” Many surveyors considered it to be a “black box” that could not be trusted. Surveyors were accustomed to having angles and distances they could write down and check the results. Also, there were some key challenges and limitations of using GPS for surveying in the early days. This included the cost and size of the equipment, the peripheral devices required, the power requirements (including 12v car batteries and generators), “black box” computer processing software, obstructions near monuments, and limited visibility of GPS satellites.

Prior to GPS becoming fully operational, some surveys had to be performed in the middle of the night to have four or more satellites visible during the observing session. This required a significant amount of technical planning, which sometimes required complicated logistics for coordinating observing sessions. Also, at that time, most private surveyors did not perform control projects, so even though GPS may be more accurate, it was not more cost-effective than classical techniques for their typical projects.

Over time, after GPS became operational, more surveyors (and other professionals) embraced using GPS after the cost of receivers decreased, user-friendly processing software became available (e.g., NGS OPUS), Continuously Operating Reference Stations were densified (e.g., NOAA CORS), and statewide Real-Time Networks (RTN) were established (e.g., North Carolina RTN). GPS technology now underpins many sciences, large areas of engineering (such as driverless vehicles and UAVs), navigation, and precision agriculture. GPS (today GNSS) and its applications have changed the way surveyors and geospatial users perform their work, and the world has seen the development of applications that were not ever imagined 50 years ago.

The Air Force was initially opposed to GPS. How did that change?

Between 1978 and at least the mid-1980s, maybe even the late 1980s, the Air Force tried several times to cancel the program. At the time, I was a Capitol Hill staffer for the House Intelligence Committee. In one of those efforts to cancel GPS, Tom Cooper, who was a lead staffer for the House Armed Services Committee, came to me and said, “Can you guys give any reason for keeping GPS?” And I said, “Yes, it greatly improves the accuracy of SIGINT [signals intelligence] locations. It makes a very big difference.”

So, Tom used that, along with other arguments, for why we should keep GPS. The Committee and Congress ultimately decided they would, despite the Air Force’s resistance.

The Air Force’s resistance came from the Strategic Air Command, which in the 1980s believed it would never use satellites. They were concerned about the satellites being shot down. I found this amusing because they were flying around in aircraft at a few thousand feet and were concerned about satellites flying at 11,000 miles. But they were, so they were laggards.

Which service adopted GPS first and why?

The service that by far led the way was the Army. It spent $100 million a year absorbing NRO capabilities. They also spent money on GPS, though not as much. By the time we got to the first Gulf War, in 1991, we had a partial GPS constellation — I think of 18 satellites of the 24 required — and that meant that you didn’t have 100% coverage all day long. So, coverage maps of their areas of interest were generated every day to let people in the field know when they would have service. Most of them didn’t have receivers either. Most of the receivers they did have were Precision Lightweight GPS Receivers (PLGR), knows as “pluggers”, which were the first “handheld” receivers, but they were pretty big.

Once the fight got going, many of the troops wrote home and asked their moms and dads to send them civilian receivers.

Yes! Thousands and thousands of them showed up in theater. Some troops taped them to the windscreens of their helicopters or jet aircraft. They were just jury-rigged into everything because, despite their limitations at the time, they were very, very useful, unlike anything else. So, now everybody realized, “Oh my goodness, this is really a big deal. This is a game changer!”

Then we got more modern receivers, integrated receivers, the whole thing. However, at the end of the Gulf War, the Air Force still had no plan to equip any of its aircraft with GPS. As Assistant Secretary of the Air Force, I was called over to the Armed Services Committee and asked, “What is your plan for integrating GPS receivers into your aircraft fleet?” I said, “There is no plan.” and they were incredulous. They looked at me like “Well, you’re an idiot.”

It wasn’t me, however, and the staff knew my story before I gave it. As a result, Congress mandated it. They put it in that year’s National Defense Authorization Act (NDAA). Within less than 10 years you had Joint Direct Attack Munitions (JDAM) and other GPS-guided weapons. So, that got it moving quickly.

By the end of the 1990s, the Air Force was fully on board and were equipping their aircraft with many weapons that depended on GPS. Meanwhile, GPS had moved to a full constellation of 24 satellites. Full operating capability was declared in 1995. The Navy proceeded similarly, but they were somewhat less affected. So, the Army remained a leader in using space.

The Chief of Staff of the Air Force asked me about Air Force use of GPS. I said, “Chief, the Air Force builds a lot of space stuff, but it doesn’t use it.” Of course, a short time later it was using it extensively. So, this ramp-up was very rapid — just a few years from “I don’t give a darn about these things” to “I can’t live without them.”

Brad Parkinson and his successors as JPO directors designed and built the system but had no role in its adoption, right?

No. They were going turn it over to the production house, if you will, and they did. Once the Air Force got on board with GPS guided weapons, adoption proceeded rapidly.

What about the Navy?

I don’t recall the Navy particularly. I do not at all accuse them of being laggards. I think they did what they needed, whatever that was.

Did later NDAAs expand that mandate to the other services?

I don’t know. I was out of the government by that time, so I lost track. I don’t think it was necessary. What people didn’t understand immediately was that you could do anything with this system. At the end of the day, it is a super accurate timing signal. There are many things you could do with that and people have done them. It quickly became evident that it was so pervasively useful, that anything you could think of involves GPS, from the era of the first Gulf War onward. By 10 years later, many weapons systems in all the services were GPS-guided. I later served on the board of ATK and we were building GPS-guided artillery rounds. I am pretty sure that the ATACMS [Army Tactical Missile System] you hear about today is GPS guided.

So, in a couple of years, all the services wanted to integrate GPS in all their platforms and weapons.

Well, except that the amazing thing was, despite all the things that people had done with GPS in the Gulf War — starting with those helicopters that went in the first night and took out the command and control system, which were guided by Army-provided pluggers taped onto the windscreens by their pilots, and downed pilots using GPS to give their coordinates to the rescue teams — at the end of the war the Air Force still didn’t have a plan to put them on its aircraft! That’s when Congress mandated it. It was amazing.

Despite that, once they got going, particularly once they got going with GPS-guided weapons, everything changed. I don’t know whether the Air Force became leaders, but they were certainly aggressive integrators of the program into the service. There was no more, “We won’t use satellites” and all that.

That was after my time. I left government in early 1993. There were other big fish to fry at the same time. As important as I realized it was, I still didn’t realize how important it was, and I was way ahead of most everybody else, in the Air Force anyway.
The Federal Aviation Administration’s (FAA’s) chief scientist at the time said, “The great thing about GPS is that it is a tool around which you can build myriad capabilities.” He outlined a few for the FAA, many of which they have since done. The same thing began to happen in the services, particularly in the Air Force, in which GPS-guided weapons were pervasive within 10 years.

Part of Brad’s motto for JPO was “The mission of this program office is, number one, to drop five bombs in the same hole.”

Yeah. By the way, one mistake that people make a lot is they think there were GPS-guided weapons during the first Gulf War. That was not the case. There were none by then. There were precision guided munitions that were guided by maps and lasers and a variety of means. But, despite the belief of many authors, there were no GPS-guided weapons at that time.

So, which was the first conflict in which GPS was used?

It was the Iraq War, in 2003. It was a major user of GPS-guided weapons.

Any other thoughts on the 50th anniversary from the military side of things?

It is impossible to overemphasize the importance to military operations and, frankly, to civilian life as well, of being able to easily and accurately navigate or have highly accurate time.
You can do it with a $100 receiver, whereas it used to require a $10,000 receiver and you had to have it re-initialized from a standard. So that’s what everybody does. Now, this has created probably more dependency than is healthy and many nations have backup that we don’t have.

Such as Loran-C. That’s a big subject of debate these days, as you know.

Well, it’s been a subject of debate for 20 years. Everybody agrees, but nobody moves.

The Department of Transportation recently released an action plan on the adoption of complementary PNT systems. So, there’s some movement.

As a one-time government bureaucrat, what you do when people are on your back is launch a study and say, “Well, it will be done in a year or two.” They have done this time, after time, after time.

There was the Volpe study more than 20 years ago.

Exactly.

“I know where we are. I do not need a satellite system to tell me!” In the 1970s and 1980s, this was the number one military and civilian response to what GPS does. The existing military hardware included navigation systems and the defense industry had a vested interest in keeping its business. Civilian interest in GPS was low because of the program’s uncertain funding. The armed services saw no reason to add a new program to their budgets and were opposed to GPS.

The military program approval process was also inconsistent with the rapid changes in digital technology. The first GPS satellite was launched in February 1978, the first PC was released in August 1981, and the first Mac in January 1984. GPS went through a development process to build user equipment, test it to make sure it met military requirements and then build the limited-rate production equipment with a design about six years old.

My favorite joint service story is that our low cost, 19-lb, $55,000, hand-carry man pack flunked its first testing sequence. The Army placed it into an alkaline bath in September 1985, that ate the o-ring and caused it to fail the bio/chem decontamination requirement. The o-ring was an Air Force requirement because at 60,000 ft without venting the device would become a potential bomb. Yet, pressure relief failed to meet the Navy Seals’ requirement for underwater operation. The fixed man pack was now our limited rate production set. Developments in digital technology during the process made it overweight, over cost and unsuitable. To get hand-carry receivers, it became necessary to purchase modern civilian sets at the unexpected outbreak of the First Gulf War in 1990.

JPO ran a competition for 200 civilian receivers that had no military requirements to send them to the operational forces for training. Trimble won the competition and when the war came the following year with only 12 GPS satellites operational, JPO asked Trimble to deliver as many sets as it could produce at the price bid for the competition to augment the deliveries of the limited rate production military set. Talk about an operational education! The Army tank drivers who did not want GPS because “The war comes to us, so we do not need GPS” instantly demanded GPS receivers when they began to get lost by more than 10 miles on the featureless desert. The deployed troops began asking their parents for GPS receivers for personal use. The war integrated GPS into all military operations.

Realizing the value of GPS inter-service integration of forces, the military believed the civilian signal should only have degraded accuracy. But in May 2000, President Clinton decided the civilians also should have good accuracy and ordered that the degradation of the civilian signal (called Selective Availability) should cease. Today everybody is aware of what GPS provides. You never hear anyone say, “I know where I am, I do not need satellites to tell me.”

The solutions aim to aid in applications such as advanced driver assistance (ADAS), robotics, mapping and more.

Polaris is a real time kinematic (RTK) corrections network that offers cm-level accurate GNSS positioning. Polaris’ global RTK network now includes the entire United States, EU, Australia, Canada and the UK.

Existing Polaris customers can utilize the UK integration immediately, at no additional cost.

This technology is complemented by the company’s FusionEngine software, which further integrates inertial measurement, wheel odometry and additional sensors to achieve the desired level of precision, even in the absence of satellite signals.

Polaris supports all major GNSS constellations and has a dense global network of base stations, which offers improved precision acquisition time in more places, the company says. The network supports all modern navigation signals across all mobile networks.

According to Point One, it is the first localization service with a modern GraphQL-based API, which aims to improve the integration of Polaris RTK into developer-built applications. It can be used by software developers to integrate RTK into demanding applications, including industrial autonomy, precision agriculture, logistics and delivery, robots and ADAS.

It will support State Space Representation (SSR) corrections delivered by L-band satellites in early 2024, the company says, which will allow for operations to continue in the absence of cellular networks or in bandwidth constrained applications.

RIEGL has released three airborne survey products. The three systems are designed to enhance sensor performances and capabilities in various segments, from terrestrial, to mobile and airborne applications.

RIEGL VQX-2 – Helicopter pod for airborne surveying

The VQX-2 helicopter pod is  designed for airborne data collection. It integrates a RIEGL laser scanner, a high-performance IMU/GNSS unit, and up to five cameras. It also can be easily mounted and dismounted onto UAVs.

The VQX-2 can be used in a variety of applications such as corridor mapping, surveying large areas from high altitudes, monitoring glaciers and landslides and more. The solution includes the corresponding cabling; a “Minor Change Approval” is already available for Airbus Helicopters AS350 series helicopters.

RIEGL VQ-680 OEM – Airborne lidar scanning module for OEM integration

The VQ-680 compact airborne lidar scanner OEM is designed to be integrated with large-format cameras or other sensors in complex hybrid system solutions.

The module can be mounted inside a camera system connected to the IMU/GNSS system and various camera modules through a sturdy mechanical interface. It also has laser pulse repetition rates of up to 2.4 MHz and 2 million measurements per second.

The VQ-680 is ideal for large-scale applications in urban mapping, forestry and power line surveying, the company says. With a wide field view of 60º and RIEGL’s nadir/forward/backward (NFB) scanning, the system offers five scan directions up to ± 20º. This technology provides users exceptional coverage of vertical structures such as building facades or power poles at high accuracy.  

The OEM’s sister type, the VQ-680, is offered as a high-end airborne lidar scanner that offers the full range of performance in a compact and lightweight scanner. This scanner can be coupled with up to six high-resolution RGB/NIR cameras and mounted onto appropriate aircraft hatches with or without using stabilized platforms. 

RIEGL VUX-180-24 –UAV lidar sensor for high-speed surveying missions 

The VUX-180-24 offers a wide field of view of 75º and a high pulse repetition rate of up to 2.4 MHz. These features – in combination with an increased scan speed of up to 800 lines per second – make it suitable for high-speed surveying missions and applications where an optimal line and point distribution is required.

Typical applications include mapping and monitoring of critical infrastructure such as power lines, railway tracks, pipelines, and runways. The  VUX-180-24 provides mechanical and electrical interfaces for IMU/GNSS integration and up to five external cameras. For smooth and straight forward data storage, an internal SSD memory with 2 TByte storage capacity and a removable CFast memory card are available.

This sensor can be coupled with RIEGL’s VUX-120, VU-160, and VUX-240 series UAVs. The system is available as a stand-alone sensor or in various fully integrated laser scanning system configurations with IMU/GNSS systems and optional cameras.

ComNav Technology has released the LS300 3D laser scanning measurement system.

The scanner utilizes simultaneous localization and mapping (SLAM) technology, and advanced real time and mapping techniques. It operates autonomously, independent of GNSS positioning, which makes it ideal for harsh conditions in both indoor and outdoor environments.

LS300 includes a 120-meter working range and a high sampling rate of 0.32 million points per second. Its point cloud accuracy is designed to perform in low reflectivity extended-range mode. The system is compatible with specialized kits, including the handheld form, back kit, car-mount and UAV kit.

The handheld mode is best suited for navigating narrow tunnels and large venues, while the backpack is designed for outdoor environments. The car mount can rapidly scan roadside facilities, and the UAV kit seamlessly pairs with the DJI M300 for aerial control. The LS 300 is suitable for a variety of applications, including smart city, digitization of underground facilities, geology, surveying and mapping, agriculture, mining and forestry.

The scanner uses a unique hybrid HSL technology. This allows for preliminary processing during the scanning process, which aims to accelerates the collection of high-precision data and expedites data processing. It offers real-time viewing of point cloud data through a mobile application and supports multiple interaction modes.

By using data processing software specifically designed and developed for the LS series by ComNav, users can handle large volumes of point cloud data and simplify complex tasks, including point cloud denoising, point cloud splicing, shadow rendering, coordinate transformation, automatic horizontal plane fitting, automatic point cloud data report generation, forward photography, and point cloud encapsulation. This allows users to efficiently process intricate point cloud data, resulting in precise measurement and modeling outcomes.

During data post-processing, users can input absolute coordinates of control points, which allows these control points to make comprehensive adjustments to the data and improve scanning data accuracy.

The LS300 also incorporates a redundant battery design with two hot-swappable batteries, designed for prolonged operation without frequent charging or interruptions. This innovative approach contributes to enhanced safety, reliability, and efficiency, the company says.

CHC Navigation (CHCNAV) has launched the Apache 3 Pro, a compact hydrographic uncrewed surface vessel (USV) designed for autonomous bathymetric surveys in shallow waters. A lightweight carbon fiber hull with IP67-rated ingress protection and semi-recessed motor provides durability and maneuverability.

Featuring CHCNAV’s GNSS RTK + inertial navigation sensor, the Apache 3 Pro offers consistent, high-precision positioning and heading data even when navigating under bridges or in areas with obstructed satellite signals. The built-in CHCNAV D270 echosounder allows for reliable depth measurement from 0.2 to 40 meters.

The Apache 3 Pro is also equipped with a millimeter-wave radar system that detects obstacles within a wide 110° field of view. When an obstacle is encountered, the USV autonomously charts a new course to safely navigate around it. The vessel uses both 4G and 2.4GHz networks to facilitate effective data transfer.

Weighing only 10 kg, it features a lightweight macromolecular polyester carbon fiber and Kevlar composite hull for improved resilience. Even with a fully integrated payload, the USV can be easily deployed and controlled by a single operator in a variety of environmental conditions.

The Apache 3 Pro ensures reliable communications through its integrated SIM and network bridge with automatic switching. It also features seamless cloud-based remote monitoring that offers real-time status updates to enhance control and security. Its semi-recessed brushless internal rotor motors minimize drafts, which can improve the USV’s maneuverability in varying water depths.

Electronic warfare in the Middle East and Ukraine is affecting air travel far beyond the battlefields, unnerving pilots and revealing unintended consequences of a tactic that experts believe will become more widespread, reported The New York Times.  

Planes are losing satellite signals, flights have been diverted and pilots have received false location reports or inaccurate warnings that they were flying close to terrain, according to European Union safety regulators and an internal airline memo viewed by The New York Times. The Federal Aviation Administration (FAA) has also warned pilots about GPS jamming in the Middle East. 

Following Russia’s invasion of Ukraine in early 2022, radio frequency interference only continues to increase across the Middle East as of autumn 2023. These interferences can involve jamming GNSS signals to obstruct or block them using noise, or mimicking signals to trick GNSS receivers into picking up counterfeit satellite signals, known as spoofing.  

Aircraft systems have been unable to detect GPS spoofing and ultimately correct for it. According to Opsgroup, an organization that monitors changes and risks in the aviation industry, one Embraer jet bound for Dubai nearly veered into Iranian airspace in September before the pilots figured out the plane was chasing a false signal. 

“We only realized there was an issue because the autopilot started turning to the left and right, so it was obvious that something was wrong,” crew members reported to Opsgroup. 

Issues arise 

With the rise of electronic warfare, the strain on aviation could be a sign of more serious economic and security issues.  

The U.S. government calls GNSS signals “an invisible utility.” Smartphones, cars, stock exchanges, data centers and countless industries rely on them for time, navigation or both. Similar systems exist around the world, such as Galileo in Europe, Glonass in Russia, QZSS in Japan, NavIC in India and BeiDou in China. One study from Britain said a five-day disruption of satellite signals could cost the country $6.3 billion. 

Minor interference with GPS signals is fairly common. GPS jamming devices, while illegal to use, are inexpensive and easy to obtain from vendors on the internet. Governments, too, have been more willing to overtly interfere with signals as a tactic in electronic warfare. 

It is not always possible to distinguish jamming from spoofing, or to determine who is behind the interference. Israel said in mid-October it had restricted GPS in the region and had warned pilots not to rely on satellite navigation systems for landing.  

Russian interference is well-documented. A 2019 report by the Washington-based analytical nonprofit group C4ADS showed extensive spoofing from a Russian-controlled air base in Syria. The report also indicated that, when Russian President, Vladimir Putin, traveled to remote locations or Russian-occupied Crimea, he was flanked by mobile GPS-spoofing technology. 

Russia has disrupted GPS signals to misdirect Ukrainian UAVs and throw precision-guided shells off their targets. Ukraine also jams Russian receivers but lacks the same level of sophistication.  

Jamming is common in conflict zones. Spoofing, until recently, was considered rare.   

The interference has been felt up to 190 miles away from battlefields and “appears to go well beyond simple military mission effectiveness,” according to Eurocontrol, Europe’s primary air-traffic-control manager. The worst-affected regions include the aerial space above the Black Sea area from Turkey to Azerbaijan; the Mediterranean Sea extending from Cyprus to Libya; the Baltic Sea near Poland and Latvia; and the Arctic near Finland and Norway. 

Airbus said it recorded nearly 50,000 interference events on its aircraft last year, more than four times as many as the year before. This came on top of an over twentyfold jump in radio-interference events from 2017 to 2018, as recorded by a voluntary incident reporting system run by Eurocontrol. Eurocontrol said the increased jamming since 2018 was most likely meant to interfere with battlefield UAVs. 

In the Middle East, there have been reports of false signals telling pilots their aircraft were directly above the airport in Tel Aviv despite being far away. Opsgroup said it had received around 50 similar reports. In some cases, onboard equipment showed that planes were approaching airports in Baghdad, Cairo or Beirut, Lebanon, when they were not. 

Looking ahead 

Spoofing is hard to distinguish because the signal appears legitimate. Only Europe’s Galileo incorporates an authentication system that can verify when a signal is from its satellites. Galileo, which currently is the most accurate and precise navigation satellite system, plans to introduce an even stronger level of authentication, according to the European Commission. 

But even Galileo’s authentication cannot protect against one of the most dreaded types of spoofing, known as “meaconing.” In a meaconing attack, a spoofer would record satellite signals, and then rebroadcast them with an amplification or a delay. Experts have not publicly confirmed any meaconing attacks in the Middle East. 

Opsgroup said the latest events should prompt manufacturers to re-examine the integration of satellite signals in aircraft electronics, known as avionics, without a safeguard that can identify false signals.

In this environment of intentional GPS jamming and spoofing, Israel has produced a leading anti-jam technology company, InfiniDome, located in Caesarea. According to co-founder Omer Sharar, the company has been working to defend GPS signals for more than seven years and has also seen the rise of devices to jam the GPS L1 frequency that anyone can buy online for $100.   

Most readily available jammer electronics only output interference disrupting GPS L1, which is commonly installed for vehicle tracking and UAV guidance. InfiniDome says it has successfully protected trucking, UAV operations and others in Israel and around the world with its Infinidome GPSdome-1 and GPSdome-2 anti-jam products. 

It is clear the conflict’s repercussions extend well beyond the battlefield, highlighting the critical need for security assessments or alternative PNT systems to protect civilians. While there is going to be a significant impact on commercial airline travel to and from Israel while hostilities continue, there is hope for a possible long-term solution for the intense jamming that has plagued the region for years.  

The Federal Aviation Administration (FAA) has granted Percepto a nationwide waiver to operate a full fleet of its UAVs remotely by one operator.

Prior to the approval, Percepto UAVs required one pilot per UAV. Now, users can operate up to 30 drone-in-a-box systems simultaneously with one pilot. The waiver aims to improve the capabilities of beyond visual line of sight (BVLOS) UAV operations across the U.S. By utilizing remote pre-flight checks and advanced automation, this waiver eliminates the need for human interference or expensive radars.

According to the company, the approval is the final regulatory step to achieve large-scale remote UAV operations, following the recent approval for nationwide BVLOS operations.

Percepto’s drone-in-a-box systems consist of a UAV that operates out of a docking station, often used in remote or hard-to-access locations. When set up with a power source and internet connection, the docking station charges and autonomously operates the UAV, allowing operations to run 24/7 and reducing reliance on human presence or interference.