RADAR - Quiz 3
Put the following "gates" in the order used by a track-while-scan radar during a normal tracking sequence:
1. Acquisition gate 2. Tracking gate 3. Turn gate
Match the following terms with the correct description: Basic Pulse RADAR Basic Continuous Wave RADAR Pulse Doppler RADAR Frequency Modulated Continuous Wave RADAR (FMCW)
Basic Pulse RADAR: Detects bearing and range to target using a single antenna Basic Continuous Wave RADAR: Detects bearing and relative velocity of target using 2 antennas. Pulse Doppler RADAR: Detects bearing, range, and relative velocity of a target using a mixer and 1 antenna. Frequency Modulated Continuous Wave RADAR (FMCW): Determines target bearing, relative velocity, and range with 2 antennas and changing frequency over a given time period.
If unambiguous RADAR range is dictating maximum detection range for a specific target, which of the following actions could an operator perform to optimize radar performance in detecting that target?
Decrease PRF to Increase Runamb Increase the Threshold Level to filter noise
True/False: A SAR antenna needs the antenna to be stationary and the target to be moving.
False
True/False: Smin must be greater than the received signal power at the antenna in order for detection.
False
Which of the following are true regarding Track While Scan (TWS) systems compared to Servo Tracking Systems?
Has a reduced track update rate compared to Servo Tracking Systems Creates a track file for individual targets Some systems employ beam splitting to enhance angular resolution. The system is able to lead the problem by calculating where the contact will be in the future.
What change in variables would result in a decreased cross range resolution for an ISAR system?
Increase in integration time Increase in frequency
Match the following terms to the correct definition: Moving Target Indicator (MTI) Bandpass filter Pulse integration Sensitivity Time Control (STC) Fast Time Constant (FTC)
Moving Target Indicator (MTI): Measures changes in return signal phase to filter out stationary targets. Bandpass filter: Used by Doppler RADARs to filter contacts based on speed. Pulse integration: The process of summing successive pulses along the same bearing in order to detect a target. Sensitivity Time Control (STC): Filters away surface-based environmental noise near the RADAR system. Fast Time Constant (FTC): Filters away atmospheric noise based on rate of change of return signals.
Which ranges do we attempt to maximize through system design, location, and operation to achieve the greatest distance our RADAR can detect (and correctly display) a target?
Over the Horizon RADAR Range Unambiguous RADAR Range Simplified Max RADAR Range
Regarding SAR and ISAR, which of the following is true?
SAR uses the motion of the transmitter/receiver to create the large aperture. ISAR uses the motion of the target to create a synthetic aperture. SAR is used to provide a high-resolution image of large non-moving targets. ISAR is extremely effective in imaging surface contacts.
RADAR cross section is dependent on which factors?
Size Shape Aspect Angle Material
Which of the following can possibly impact maximum detection range for a RADAR system?
Transmission frequency Shape of the target pulse width and rest time Height of our antenna
What variables enhance SAR cross range resolution
increased distance traveled by antenna
Servo-controlled tracking systems require an error signal as feedback to adjust the radar position. Because of this, servo trackers will always:
lag the target
A Synthetic Aperture Radar (SAR) achieves a large effective aperture by:
using motion of the transmitter/receiver.
