GPS-denied

Deutsch: GPS-verweigert / Español: Denegado por GPS / Português: Negado pelo GPS / Français: Refusé par GPS / Italian: Negato dal GPS

GPS-denied refers to environments or situations where the Global Positioning System (GPS) signals are unavailable or unreliable. In the context of the space industry, this term is used to describe scenarios where traditional satellite-based navigation and positioning systems cannot be used due to various factors such as signal blockages, interferences, or the inherent limitations of the GPS system in certain locations, like deep space or subterranean environments on other planets.

Description

In the space industry, the term GPS-denied pertains to the challenges faced by spacecraft, rovers, and other space-faring vehicles when navigating in environments where GPS signals are not accessible. GPS relies on signals from a network of satellites orbiting Earth, but these signals can be obstructed or completely absent in several scenarios encountered in space exploration. For instance, when operating on the far side of the moon, within Martian caves, or deep within the Jovian atmosphere, the absence of GPS signals necessitates alternative navigation and positioning methods.

The importance of addressing GPS-denied environments in space exploration is significant, as reliable navigation and positioning are crucial for mission success. Without accurate location data, autonomous rovers cannot traverse alien terrains safely, spacecraft may struggle with precise landings, and scientific instruments could fail to target specific areas of interest effectively.

Application Areas

In the space industry, GPS-denied navigation is critical in various scenarios, including:

1. Lunar Missions: Exploring and operating on the moon's far side or within lunar caves where GPS signals from Earth cannot reach.
2. Martian Exploration: Navigating on Mars, especially in areas with obstacles that block signals, such as canyons, caves, and heavily dusted regions.
3. Deep Space Missions: Spacecraft operating far from Earth, beyond the reach of GPS satellites, require alternative navigation systems.
4. Asteroid Mining: Positioning and navigating spacecraft in close proximity to asteroids where no GPS signals are available.
5. Subsurface Exploration: Rovers exploring beneath the surfaces of other planets or moons, where GPS signals are obstructed.

Well-Known Examples

Examples of solutions and technologies developed to address GPS-denied environments in space include:

• Inertial Navigation Systems (INS): Utilizing gyroscopes and accelerometers to track the position and orientation of spacecraft or rovers based on their movement from a known starting point.
• Star Trackers: Instruments that determine the spacecraft's orientation by observing the positions of stars, which are used as reference points.
• Visual Odometry: Techniques that use camera images to track the movement of a rover or lander by comparing changes in the landscape.
• LIDAR (Light Detection and Ranging): Using laser pulses to map the terrain and assist in navigation by providing detailed topographical information.
• Radio Frequency Navigation: Employing signals from multiple radio sources to triangulate position when GPS signals are unavailable.

Special Considerations

Alternative Navigation Technologies

The development and integration of alternative navigation technologies are essential to overcome GPS-denied challenges. Autonomous systems that combine multiple sensors and data sources can enhance reliability. Machine learning algorithms and AI-driven systems are also being explored to improve real-time decision-making and navigation accuracy in these environments.

Similar Terms

• Non-GPS Navigation: Navigation methods that do not rely on GPS, encompassing a wide range of techniques and technologies.
• Alternative Positioning Systems: Systems designed to provide location and navigation data using methods other than GPS.
• Autonomous Navigation: The capability of a spacecraft or rover to navigate and make decisions independently without human intervention.

Summary

GPS-denied environments in the space industry present unique challenges for navigation and positioning. Addressing these challenges involves developing and employing alternative technologies such as inertial navigation systems, star trackers, visual odometry, LIDAR, and radio frequency navigation. These solutions ensure that space missions can continue to explore and operate effectively, even in areas where traditional GPS signals are unavailable, thereby enhancing the potential for discovery and mission success in the vast and varied landscapes of space.

--