“I knew I was going to take the wrong train, so I left early.”
In rail transportation, GNSS is used in conjunction with other technologies to track the location of locomotives and rail cars, maintenance vehicles and wayside equipment for display at central monitoring consoles. Knowing the precise location of rail equipment reduces accidents, delays and operating costs, enhancing safety, track capacity and customer service.
In aviation, GNSS is being used for aircraft navigation for departure, en route and landing. GNSS facilitates aircraft navigation in remote areas that are not well served by ground-based navigation aids, and it is a significant component of collision-avoidance systems, and systems used to improve approaches to airport runways. Refer to Chapter 5 for information about WAAS, a regionally based system across North America that delivers GPS corrections and a certified level of integrity to the aviation industry, enabling aircraft to conduct precision approaches to airports.
In marine transportation, GNSS is being used to accurately determine the position of ships when they are in the open sea and when they are manoeuvring in congested ports. GNSS is incorporated into underwater surveying, buoy positioning, navigation hazard location, dredging and mapping.
In surface transportation, vehicle location and in-vehicle navigation systems are being used throughout the world. Many vehicles are equipped with navigation displays that superimpose vehicle location and status on maps. GNSS is used in systems that track and forecast the movement of freight and monitor road networks, improving efficiency and enhancing driver safety.
Using GNSS, shipping hubs can improve their operating efficiency by tracking the movement and placement of containers throughout their yards.
Gantry cranes are used in ports throughout the world to lift shipping containers, as shown in Figure 61. These cranes are large and sometimes difficult to steer accurately in a crowded shipping dock. Many cranes are equipped with GNSS-based steering devices that determine the crane’s position and keep it travelling in the desired path, improving accuracy and productivity as well as the safety of operators and workers on the ground. A key benefit is the quick movement of containers about the port, which reduces food spoilage and gets freight delivered on time.
One of the most exciting applications of GNSS is enabling autonomous driving — both on-road and off-road. As discussed in Chapter 8, the Society of Automotive Engineers (SAE) has defined levels of vehicle automation from 0 to 5 (Figure 52). Above Level 3, the vehicle monitors the environment and performs driving tasks. The positioning accuracy, reliability and integrity needed to enable safety-critical autonomy requires a combination of high-precision GNSS technologies, sensors and corrections. A few of the initial applications of autonomous vehicles include university campus shuttles, last-mile product delivery and taxis. Several universities are engaged in research to develop autonomous vehicle platforms. One example is the University of Iowa’s Automated Driving Systems (ADS) for Rural America project, which is now driving a partially automated shuttle bus through rural Iowa to enhance mobility for transportation-challenged populations such as the aging in rural communities.
An article (On the Rural Road to Autonomy) about the ADS for Rural America is in the 2022 Velocity magazine available at: resources.hexagonpositioning.com/rural-road-autonomy
In the Canadian city of Calgary, paying for on-street parking has become automated. Customers pay for parking at street side terminals or using their smartphone, and monitoring of the parked vehicles is done from a vehicle equipped with cameras and a GNSS receiver.
When a customer pays for parking, they enter the licence plate of their vehicle, a code that identifies the parking area and the amount of parking time required. This information is sent to a database. As the monitoring vehicle drives along the street, the vehicle cameras capture the licence plates of the parked cars. The licence plate number, along with the time and position provided by the GNSS receiver, is compared to the database of paid parking. If a vehicle is not found in the database, the photograph is sent to a Calgary Parking Authority employee so they can determine if there is a just cause (e.g., people are just getting out of the car), there is a mistake in identifying the licence plate (e.g., a D is mistaken for an O) or if it is a parking violation.
Due to the tight urban corridors in downtown Calgary, the location reported by the GNSS-only system on the monitoring vehicles was misplacing 6-7% of the vehicles (approximately 1,400 vehicles) per day and the vehicles could be misplaced by up to 600 metres (657 yards). This misplacement caused many hours of extra work each day for Calgary Parking Authority employees, because they had to manually correct the vehicle's position before they could determine if there was a parking violation.
By switching from a GNSS-only system to a GNSS+INS system, the monitoring vehicle was able to overcome the GNSS challenges in downtown Calgary and provide a much more reliable position. The GNSS+INS system reduced the number of misplaced cars to 1% (less than 300 vehicles), saving the Calgary Parking Authority enough work hours to pay for the GNSS+INS system in all their monitoring vehicles in under two years.
An article (Calgary ParkPlus Program, City-Wide Positional Accuracy) about how GNSS+INS has helped the Calgary Parking Authority is in the 2014 Velocity magazine available at: resources.hexagonpositioning.com/calgary-parkplus-program.
Guiding snowplows in the Andes
The high mountain roads in the Andes mountains of Argentina provide important links for local communities, cross-border traffic and trade. During the winter months, these snowbound roads are difficult to navigate and sometimes dangerous. Even the vehicles and machinery used to keep these routes open need help to navigate when snowdrifts make the roadways difficult to follow.
For the snowplows keeping these roads clear, a GNSS receiver with PPP positioning technology is used to ensure the snowplow stays on the road even when the driver cannot see the road or signs.
An article (MicroElect takes positioning into the Andes Mountains) about how GNSS has helped snowplows in Argentina is in the 2019 Velocity magazine available at: resources.hexagonpositioning.com/microelect-positioning-andes-mountains.