Method

Advantages

Disadvantages

Operating range

Performance

Horizon sensor

scanner

fixed head

Infrared sensing of earth limb

Low operating range

LEO

≤0.1˚ to 0.25˚

Magnetometer

Simple, reliable, high weight

Uses Earth magnetic field

Requires separation from payload

LEO

0.5˚ to 3˚

GPS

High accuracy

full NAV solution

Requires GPS system maintenance

signal multipath

LEO (GPS orbit)

0.3˚ to 0.5˚

(requires antenna separation)

Sun sensor

Can use data from observing payload

Requires unobstructed view of sun

LEO to interplanetary

0.005˚ to 3˚

Inertial measurement unit (gyros and accelerometers)

Angular rate data and acceleration

Requires external aiding

LEO to interplanetary

Gyro drift rate:

0.003˚/h to 1˚/h

accel linearity:

1 to 0.000005 g/g²

Star sensor

camera

Tracker/mapper

High accuracy

Moderate to high cost

LEO to interplanetary

0.0003˚ to 0.01˚