Sun sensors are among the most fundamental sensors used in satellite attitude determination. They work by detecting the presence and direction of the Sun. Coarse sun sensors (CSS) typically provide a simple output, such as a voltage or a digital signal, indicating whether the Sun is within their field of view. These are useful for initial satellite orientation and as a backup. Fine sun sensors (FSS) offer more precise measurements, often providing a vector pointing towards the Sun. These are critical for accurate attitude control and can be used to determine two axes of the satellite's orientation. Their primary limitation is their dependence on the Sun being visible, making them less effective during eclipses or in deep space far from the Sun.

Star trackers are considered the gold standard for high-precision attitude determination. They function like digital cameras that continuously image the celestial sphere. An onboard processor compares the observed star patterns to a stored catalog of stars. By identifying a sufficient number of stars and their positions, the star tracker can calculate the satellite's precise orientation in three dimensions with very high accuracy (often within arcseconds). They are robust against solar interference and provide continuous attitude information, making them ideal for missions requiring precise pointing. However, they are more complex, power-hungry, and susceptible to temporary blindness from bright light sources like the Earth or Moon.

Earth sensors are designed to detect the infrared radiation emitted by the Earth's atmosphere or surface, effectively identifying the Earth's limb. These sensors are crucial for nadir-pointing satellites (those that always point towards the Earth's center) or for maintaining a specific Earth-relative orientation. They typically provide signals that allow the satellite to determine its pitch and roll angles relative to the Earth's horizon. Different types exist, including infrared horizon sensors (IRHS) and Earth limb sensors. Their accuracy can be affected by atmospheric conditions, cloud cover, and the presence of bright light sources near the limb.

Magnetometers are used to measure the Earth's magnetic field vector. Since the Earth's magnetic field has a known (though complex) spatial distribution, measuring the field at the satellite's location can provide information about its orientation. Magnetometers are relatively simple, low-power, and robust sensors. They are particularly useful in Low Earth Orbit (LEO) where the magnetic field is strong. However, their accuracy is limited by the complexity and variability of the Earth's magnetic field, and they are susceptible to magnetic interference from the satellite's own components. They are often used for coarse attitude determination or as a backup to other sensors.

Gyroscopes are inertial sensors that measure angular velocity, i.e., how fast the satellite is rotating around its axes. They do not provide an absolute orientation but rather track changes in orientation over time. This makes them invaluable for smoothing out attitude data, providing attitude information during periods when other sensors are unavailable (e.g., during eclipses for sun sensors), and for precise short-term attitude control. Modern satellites often use Solid-State Gyros (SSGs) or Fiber-Optic Gyros (FOGs). While highly accurate for measuring rates, gyroscopes are prone to drift over longer periods, requiring periodic recalibration using absolute attitude sensors like star trackers or sun sensors.