What type of antenna is used in GPS systems?

Aeronautical & Aerospace Engineering : Avionics - Quiz(MCQ)

Yagi antenna

Loop antenna

Helical array antenna

Parabolic antenna

Correct Answer : Helical array antenna

Explanation : The GPS antenna array is formed by an inner quad helices encircled by a ring of eight outer helices that provide near equal power to all terrestrial users. The helical antenna is optimum since circular polarization is least affected by weather and atmosphere.

Recently Updated in Avionics Questions

Why is the gyro and accelerometers shock mounted to the body?

Reduce drift error

Impact protection

Limit vibration errors

Prevent voltage surges

Correct Answer : Option (C) : Limit vibration errors

Explanation : The gyros and accelerometers are rigidly mounted on a block with temperature sensors. The block is usually shock mounted to the vehicle to control the bandwidth of the motion sensed at the instruments. Shock mounting limits vibration rectification errors within the errors themselves.

Pre-processing algorithms are also called as ________

Resolution algorithm

Coning algorithm

Differential algorithm

Error control algorithm

Correct Answer : Option (B) : Coning algorithm

Explanation : Pre-processing the gyro data at a higher rate than the quaternion iteration improves the approximation in the vector change in angle in order to follow the actual motion of the rotation axis closely. The pre-processing algorithm is also called as coning algorithms.

Which of the following is false with respect to gimballed platform?

Protect the instruments from large angular motion

Euler angles are not easily readable from the gimbals

Protection from vibration, temperature and magnetic effects

Orients the accelerometers into a coordinate frame relative to Earth

Correct Answer : Option (B) : Euler angles are not easily readable from the gimbals

Explanation : One of the main purposes of gimballed system is to provide a convenient readout of vehicle attitude by reading each of the gimbals angles separately, thereby yielding convenient Euler angle outputs.