 ranging, also known as LiDAR, and vision aided navigation.
NovAtel SPAN technology describes our software that combines GNSS and INS positioning, as well as the hardware built to measure GNSS signals and IMU measurements. GNSS and INS solutions can be combined and integrated at various levels, from deeply coupled, to tightly coupled, to loosely coupled. This coupling describes how integrated GNSS and INS technologies and measurements are in the solution. Our introduction to GNSS book goes into more detail about loosely coupled, tightly coupled, and deeply coupled solutions.
Odometers track the velocity of a ground vehicle and can offer an independent measurement of distance to the GNSS and INS solution, especially when GNSS signals are disrupted. This is especially useful in GNSS signal outages, such as a tunnel.
LiDAR systems use pulses of light to understand the solution’s surroundings. Each light pulse that is emitted from the LiDAR unit gets reflected from various surfaces, allowing the system to compute a range between the sensor and any surrounding objects.
By monitoring the solutions range to an upcoming point with a known position, LiDAR can help improve position accuracy in an obstructed area, such as an urban environment. This is also an example of combining various types of data, positioning and point cloud data, to provide meaningful information about the location.
Here’s an example of a point cloud data map from a mobile mapping application. The lasers on the LiDAR device mapped the ground, the location of the trees and bridge. Darker green indicates the closer distance to the bottom of the canyon, while objects become light green to orange the further away they were. As the vehicle moves through the point cloud, it can match its current range to various objects (trees, bridge, etc.) to a previous range to the same object and estimate the change in position over time.
Vision aided navigation is also called photogrammetry. This concept is very similar to LiDAR, except the system is now using cameras instead of laser beams. Usually, this kind of system takes the form of cameras to identify objects as reference points. The solution can then calculate relative position to those reference points, as well as a general heading to know what direction the solution is moving in.
This is by no mean a comprehensive list of all the sensors that can be used to aid GNSS. The technologies listed here are just a sample of some of the more widely used techniques.
Sensor Fusion Across Industries
There are many different applications for a combined GNSS and INS solution, including automotive and agriculture. Not only can SPAN track the movement of a ground vehicle, but the trusted position can also be used to ensure it stays on a specified path. This is a fundamental technology used for autonomous cars and tractors.
In a marine environment, the right GNSS+INS solution would be able to compensate for heave motions from waves. For mobile mapping, INS sensors can monitor the subtle changes in position, velocity, and attitude on a small device carried by its user, while using LiDAR to collect 3D point cloud data about the user's surroundings.
Sensor fusion with GNSS and INS technologies creates a comprehensive positioning solution that extends and verifies an accurate position in moving objects. They are very complementary technologies.
Hexagon | NovAtel Business Development Manager for Defense and Military Peter Soar introduces the strategies and methods to protect GNSS positioning in a contested environment. Through specialized equipment and algorithms, Peter demonstrates how we can protect position, navigation, and timing (PNT) information from jamming and spoofing.
Hello, welcome to episode six of the NovAtel webinar series on An Introduction to GNSS. I’m Peter Soar, the business development manager for defense and military at NovAtel in Hexagon Autonomy and Positioning.
Here, we’ll explore techniques for delivering GNSS time and position in conditions where it is made difficult by unintentional or deliberate interference. Whi