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An Inertial Navigation System (INS) is designed to operate independently of external radio signals for continuous position updates.
Answer: False
An INS calculates position and velocity through dead reckoning using internal sensors, making it immune to external signal dependencies or interference.
While an INS can operate without external updates for a period, its accuracy degrades over time due to drift, limiting its utility as a primary system for extended durations without recalibration or augmentation.
Answer: True
INS accuracy degrades over time due to integration drift. For long-duration primary navigation, it typically requires periodic updates from external sources like GPS or other navigation aids.
What is the fundamental principle by which an Inertial Navigation System (INS) determines an object's movement?
Answer: Dead reckoning using motion sensor data
An INS determines an object's movement through dead reckoning, which involves continuously calculating position, orientation, and velocity using data from internal motion sensors like accelerometers and gyroscopes.
Which pair of sensors constitutes the fundamental components of an Inertial Navigation System?
Answer: Accelerometers and gyroscopes
The core sensors in an Inertial Navigation System are accelerometers, which measure linear acceleration, and gyroscopes, which measure angular velocity.
What is the principal advantage of an Inertial Navigation System (INS) once initialized, rendering it resilient to specific external threats?
Answer: Its ability to operate without external references
Once initialized, an INS can autonomously track position and velocity using internal sensors, making it immune to external signal jamming or deception.
How does an Inertial Navigation System (INS) calculate an object's position?
Answer: By integrating linear acceleration measurements twice
An INS calculates position by first integrating the measured linear accelerations (in the inertial frame) to determine velocity, and then integrating the velocity over time to find the position.
What is the primary function of gyroscopes within an Inertial Navigation System (INS)?
Answer: To measure angular velocity and determine orientation.
Gyroscopes are essential in an INS for measuring angular velocity, which allows the system to determine and track the orientation of the vehicle.
In an Inertial Navigation System (INS), gyroscopes are responsible for measuring angular velocity, while accelerometers measure linear acceleration.
Answer: True
Gyroscopes detect changes in orientation (angular velocity), whereas accelerometers measure the rate of change in velocity (linear acceleration).
Fiber Optic Gyroscopes (FOGs) do not suffer from laser lock at low rotation rates, unlike Ring Laser Gyros (RLGs).
Answer: True
Ring Laser Gyros (RLGs) are susceptible to 'lock-in' or 'laser-lock' at low rotation rates, a phenomenon that Fiber Optic Gyroscopes (FOGs) do not experience.
A closed-loop accelerometer employs a feedback system to maintain the sensing mass in a stationary position, determining acceleration by measuring the magnitude of the counteracting force.
Answer: True
In a closed-loop accelerometer, a feedback mechanism nullifies the deflection of the sensing mass, and the acceleration is inferred from the force required to achieve this nullification.
Micro-Electro-Mechanical Systems (MEMS) gyroscopes predominantly utilize the Coriolis effect to ascertain angular velocity.
Answer: True
MEMS gyroscopes operate by detecting the Coriolis force, which arises when a vibrating mass experiences angular motion.
Micro-Electro-Mechanical Systems (MEMS) gyroscopes are typically less expensive and simpler to manufacture compared to Ring Laser Gyros (RLGs).
Answer: True
MEMS gyroscopes are generally more cost-effective and easier to manufacture than Ring Laser Gyros (RLGs).
Quartz rate sensors, commonly referred to as 'tuning fork gyros,' function by leveraging the Coriolis force, which is generated when a vibrating mass is subjected to an angular rate.
Answer: True
Tuning fork gyros, or quartz rate sensors, operate on the principle of the Coriolis force acting upon a vibrating mass when angular velocity is applied.
Open-loop accelerometers determine acceleration by measuring the deflection of a proof mass that is attached to a spring mechanism.
Answer: True
In an open-loop accelerometer, acceleration causes a spring-mounted mass to displace, and this deflection is directly measured to infer the acceleration.
Hemispherical Resonator Gyros (HRGs) operate by inducing a standing wave within a hemispheric structure, which shifts in response to the Coriolis force, thereby detecting rotation.
Answer: True
HRGs function by measuring the angular shift of a standing wave pattern within a hemispheric resonator, a shift caused by the Coriolis effect during rotation.
Ring Laser Gyros (RLGs) measure rotation by splitting a laser beam into two counter-propagating paths and detecting a phase shift induced by the Sagnac effect.
Answer: True
RLGs operate by utilizing the Sagnac effect, which causes a phase difference between two laser beams traveling in opposite directions within a rotating ring.
How do Fiber Optic Gyroscopes (FOGs) differ from Ring Laser Gyros (RLGs) concerning their susceptibility to low rotation rates?
Answer: RLGs suffer from lock-in, while FOGs do not.
Ring Laser Gyros (RLGs) are prone to 'lock-in' at low rotation rates, a phenomenon that Fiber Optic Gyroscopes (FOGs) do not experience.
What is the primary purpose of the feedback system within a closed-loop accelerometer?
Answer: To cancel the mass's deflection and measure the counteracting force.
The feedback system in a closed-loop accelerometer is designed to nullify the deflection of the sensing mass, with acceleration being determined by the magnitude of the counteracting force required.
MEMS gyroscopes detect rotation by utilizing which fundamental physical principle?
Answer: The Coriolis effect
MEMS gyroscopes primarily rely on the Coriolis effect to measure angular velocity by detecting the motion induced in a vibrating proof mass.
What is the key difference distinguishing open-loop from closed-loop accelerometers?
Answer: Closed-loop uses feedback to cancel deflection and measure counteracting force.
The fundamental difference is that closed-loop accelerometers employ a feedback system to nullify the sensing mass's deflection and measure the counteracting force, whereas open-loop accelerometers measure the deflection directly.
How does a Ring Laser Gyro (RLG) detect rotation?
Answer: By splitting a laser beam and measuring a phase shift due to the Sagnac effect.
A Ring Laser Gyro (RLG) detects rotation by splitting a laser beam into two paths traveling in opposite directions around a closed loop, measuring the phase shift caused by the Sagnac effect.
What is the fundamental principle behind Hemispherical Resonator Gyros (HRGs)?
Answer: Inducing a standing wave in a hemispheric structure and measuring its shift due to the Coriolis force.
HRGs operate by exciting a standing wave within a hemispheric structure and measuring the resulting shift in this wave pattern, caused by the Coriolis force, to determine rotation.
What is the primary challenge encountered in the development and manufacturing of Fiber Optic Gyroscopes (FOGs) relative to Ring Laser Gyros (RLGs)?
Answer: FOGs require more complex calibrations.
The development and manufacture of FOGs present greater technical challenges than RLGs, primarily due to the requirement for more complex calibration procedures.
How does a MEMS gyroscope detect rotation?
Answer: By acting on a resonating proof mass with a Coriolis force, causing motion that is measured.
A MEMS gyroscope detects rotation by applying a Coriolis force to a resonating proof mass, which induces a measurable motion proportional to the angular velocity.
Gimbal lock is a phenomenon that affects gimballed INS systems, causing them to lose orientation.
Answer: True
Gimbal lock is a mechanical issue that occurs in gimballed inertial navigation systems when the gimbals align, restricting the system's ability to sense rotation about one axis.
The North-East-Down (NED) reference frame is frequently utilized for attitude and position calculations within Inertial Navigation Systems.
Answer: True
The North-East-Down (NED) frame is a standard navigational reference system commonly employed in INS calculations for determining orientation and position.
The principal drawbacks of gimballed inertial navigation systems include their vulnerability to gimbal lock and the inherent presence of numerous moving mechanical parts.
Answer: True
Gimballed systems are susceptible to gimbal lock and have a higher failure rate due to their reliance on many moving mechanical components.
Fluid bearings, utilizing pressurized gas or oil, are employed in gyrostabilized platforms to eliminate the necessity for conventional slip rings and bearings.
Answer: True
Fluid bearings provide a low-friction support for gyrostabilized platforms, negating the need for traditional slip rings and bearings by using a pressurized fluid cushion.
The primary advantage of strapdown systems over gimballed systems lies in their mechanical simplicity and elimination of gimbals, not a reduced need for complex data updating algorithms.
Answer: True
Strapdown systems offer advantages such as mechanical simplicity and elimination of gimbal lock, but they require more complex data updating algorithms compared to gimballed systems.
Motion-based alignment techniques enable INS initialization while the vehicle is in motion, rather than requiring it to be stationary.
Answer: True
Motion-based alignment, such as 'Align in Motion,' allows for the initialization of an INS using data collected while the vehicle is moving, often leveraging GPS for position history.
Which reference frame is commonly employed for calculating attitude and position within Inertial Navigation System (INS) navigation equations?
Answer: North-East-Down (NED)
The North-East-Down (NED) frame of reference is frequently utilized in INS navigation equations for calculating attitude and position.
What is the primary advantage offered by strapdown systems in comparison to gimballed systems?
Answer: They are simpler to calibrate and have fewer moving parts.
Strapdown systems eliminate the need for gimbals, resulting in simpler calibration, fewer mechanical parts, and increased reliability compared to gimballed systems.
Robert Goddard, a pioneer in rocketry, is recognized for his early experiments with rudimentary gyroscopic stabilization systems for rockets.
Answer: True
Robert Goddard, an American rocketry pioneer, conducted early experiments involving gyroscopic systems to stabilize rockets.
The guidance system employed in the V-2 rocket was an integrated assembly of gyroscopes, accelerometers, and a basic analog computer.
Answer: True
The V-2 rocket's guidance system incorporated gyroscopes and accelerometers, processed by a simple analog computer, to control its flight path.
The 'Q system' of missile guidance represented a significant advancement, employing vector cross products for autopilot rate signals, a method termed 'cross-product steering'.
Answer: True
The 'Q system' introduced 'cross-product steering,' a novel method that utilized vector cross products for fundamental autopilot rate signals.
The Delco Carousel Inertial Navigation System (INS) was initially implemented in the Boeing 747 aircraft, not the Boeing 707.
Answer: True
Delco Electronics' Carousel INS was first integrated into the early models of the Boeing 747 aircraft.
The Apollo spacecraft's guidance system, which utilized a gimballed platform, was designed to manage the risk of gimbal lock through careful mission planning rather than employing strapdown technology.
Answer: True
The Apollo guidance system used a gimballed platform and required careful maneuver planning to prevent gimbal lock, as it did not employ strapdown technology.
The Space Shuttle employed open-loop guidance only during its initial ascent phase, transitioning to other guidance methods thereafter.
Answer: True
The Space Shuttle utilized open-loop guidance from lift-off until Solid Rocket Booster (SRB) separation, after which it transitioned to Powered Explicit Guidance (PEG).
A primary driver for the military's effort to decrease reliance on GPS is the concern over the potential for signal jamming and deception.
Answer: True
Military entities are motivated to reduce GPS dependence due to the vulnerability of GPS signals to jamming and deceptive countermeasures.
The image of the Apollo program's inertial measurement unit depicts a gimballed gyrostabilized platform, not a strapdown system.
Answer: True
The inertial measurement unit shown from the Apollo program is a gimballed system, which contrasts with modern strapdown configurations.
The USAF C-141 was the first military aircraft to use the Delco Carousel INS in a triple system configuration.
Answer: False
The USAF C-141 was the initial military aircraft to employ the Delco Carousel INS in a dual system configuration; the C-5A later adopted a triple INS configuration.
Who is credited with pioneering early experimentation involving rudimentary gyroscopic systems for rocket stabilization?
Answer: Robert Goddard
Robert Goddard, an American rocketry pioneer, conducted early experiments involving gyroscopic systems to stabilize rockets.
What was the significance of the 'Q system' in the field of missile guidance?
Answer: It introduced "cross-product steering" using vector cross products.
The 'Q system' was significant for introducing 'cross-product steering,' a method that utilized vector cross products as fundamental autopilot rate signals.
Which company was responsible for producing the Inertial Measurement Units (IMUs) utilized in the Apollo program?
Answer: Delco Electronics
Delco Electronics manufactured the Inertial Measurement Units (IMUs) for the Apollo program, working alongside Kollsman Instrument Corp. and Raytheon on other system components.
The Delco Carousel Inertial Navigation System (INS) was a widely adopted system for which mode of transportation?
Answer: Commercial aircraft
The Delco Carousel INS gained significant popularity and was widely implemented in commercial aircraft, enhancing navigation capabilities.
What historical event facilitated the contribution of Wernher von Braun and German rocket scientists to U.S. rocket research programs?
Answer: Operation Paperclip
Operation Paperclip was the U.S. initiative that brought Wernher von Braun and approximately 500 German rocket scientists to the United States after World War II, significantly advancing American rocket technology.
What is the primary reason the military seeks to reduce its dependence on GPS?
Answer: The potential for GPS signals to be jammed or deceived.
The military's desire to reduce GPS dependence stems from the vulnerability of GPS signals to jamming and deceptive techniques, making alternative navigation methods crucial.
What does the depicted image of an inertial navigation unit represent?
Answer: The inertial navigation unit of the French S3 missile.
The image depicts the inertial navigation unit that was part of the French S3 missile system.
Integration drift in an Inertial Navigation System (INS) is a consequence of sensor inaccuracies, not their perfect accuracy.
Answer: True
Integration drift arises from the cumulative effect of small errors in sensor measurements (accelerometers and gyroscopes) over time, leading to increasing positional inaccuracies.
DARPA's Micro-PNT program is focused on developing Timing & Inertial Measurement Unit (TIMU) chips, which integrate 3-axis gyroscopes, 3-axis accelerometers, and 3-axis magnetometers.
Answer: True
The DARPA Micro-PNT initiative aims to create TIMU chips that combine gyroscopic, accelerometric, and magnetometric sensors on a single platform.
A Timing & Inertial Measurement Unit (TIMU) chip integrates a 3-axis gyroscope, a 3-axis accelerometer, and a 3-axis magnetometer, complemented by a master timing clock.
Answer: True
TIMU chips are designed to incorporate a full suite of inertial sensors (gyroscope, accelerometer, magnetometer) and a timing clock for comprehensive navigation and timing data.
Schuler tuning is a critical principle applied to Inertial Navigation Systems (INS) operating near Earth's surface to mitigate errors caused by the planet's rotation.
Answer: True
Schuler tuning is an essential concept in INS design that compensates for errors introduced by Earth's rotation, ensuring platform stability relative to the local vertical.
What is 'integration drift' in the context of Inertial Navigation Systems (INS)?
Answer: The accumulation of errors due to sensor inaccuracies over time
Integration drift refers to the progressive increase in error within an INS, resulting from the cumulative effect of small inaccuracies in sensor measurements being integrated over time.
Which of the following represents a common method for managing or correcting Inertial Navigation System (INS) drift?
Answer: Supplementing the INS with GPS or air data computers
INS drift is commonly managed by augmenting the system with external data from sources such as GPS receivers or air data computers, which provide periodic corrections.
What is the primary objective of DARPA's Micro-PNT program regarding the development of navigation chips?
Answer: To develop TIMU chips capable of absolute position tracking without GPS.
DARPA's Micro-PNT program aims to develop TIMU chips capable of achieving absolute position tracking on a single chip, independent of GPS signals.
What is the purpose of Schuler tuning in Inertial Navigation Systems (INS) operating near Earth's surface?
Answer: To prevent errors related to Earth's rotation by keeping the platform pointed towards Earth's center.
Schuler tuning is applied to INS systems near Earth's surface to counteract errors caused by Earth's rotation by ensuring the navigation platform remains aligned with the local vertical.
What technological advancement has facilitated the application of Inertial Navigation Systems (INS) in fields such as human motion capture?
Answer: Advances in microelectromechanical systems (MEMS) technology.
Significant advancements in microelectromechanical systems (MEMS) technology have enabled the creation of small, lightweight, and cost-effective inertial sensors, expanding INS applications to areas like human motion capture.
What is the function of the 'zero velocity updates' technique in managing Inertial Navigation System (INS) drift?
Answer: It periodically resets velocity to zero when the vehicle is stationary.
The 'zero velocity updates' technique periodically resets the INS velocity to zero when the vehicle is confirmed to be stationary, thereby mitigating accumulated drift.
In the graphic comparing navigation systems, what element visually represents accuracy?
Answer: The radius of a circle.
The graphic uses the radius of a circle to visually indicate the accuracy of different navigation systems, where a smaller radius signifies higher accuracy.
What is the purpose of integrating a master timing clock into a TIMU chip?
Answer: To enable simultaneous measurement of motion and timing data.
Integrating a master timing clock into a TIMU chip allows for the simultaneous measurement and correlation of motion data with precise timing information.