Open Loop Fiber Optic Gyroscope

The SG-1 open-loop fiber optic gyroscope (FOG) is a high-reliability inertial measurement device specifically designed to accurately measure the angular rate of rotation of its mounting carrier relative to the inertial space. As a core component of inertial measurement systems, it operates based on the Sagnac effect-an optical phenomenon that generates a phase difference between two counter-propagating light beams traveling along a closed optical fiber loop when the loop rotates, and this phase difference is directly proportional to the angular rate of the rotation.

Unlike closed-loop fiber optic gyroscopes that employ feedback control mechanisms to compensate for signal deviations, the SG-1 open-loop configuration features a simple structural design, low power consumption, and high stability, making it well-suited for scenarios where cost-effectiveness and long-term operational reliability are prioritized. Its core function is to real-time detect and output the rotational speed of the mounted product along the sensitive axis of the carrier, with the measurement accuracy and dynamic response performance tailored to meet the practical requirements of low-precision inertial measurement scenarios.

In terms of application scope, the SG-1 open-loop fiber optic gyroscope is mainly oriented to the low-precision demand fields of flight control and servo control. Specifically, in the field of flight control, it is widely used in small unmanned aerial vehicles (UAVs), light aircraft, and general aviation equipment, providing real-time rotational angular rate data for the flight control system to assist in stabilizing the aircraft attitude, adjusting flight trajectory, and ensuring flight safety-especially in low-altitude, low-speed flight scenarios where high-precision inertial measurement is not required but stable and continuous data output is essential.

In the field of servo control, the SG-1 open-loop FOG plays a crucial role in industrial servo systems, such as mechanical arm rotation control, turntable stability control, and precision instrument positioning. It provides accurate rotational speed feedback for the servo controller, enabling the controller to adjust the output torque and speed in real time, thereby improving the stability and control accuracy of the servo system, reducing mechanical vibration and positioning errors, and ensuring the smooth operation of mechanical equipment.

Additionally, the SG-1 open-loop fiber optic gyroscope also exhibits excellent environmental adaptability, capable of operating stably in harsh working environments such as wide temperature ranges (-40℃ to 85℃), high humidity, and strong electromagnetic interference. This advantage further expands its application scenarios, making it applicable to various industrial, aerospace, and marine low-precision inertial measurement and control systems, providing reliable technical support for the stable operation of related equipment.

1. Superior Precision Performance

The product achieves exceptional sensitivity and measurement accuracy within its size category. Compared with similar products of the same size, it maintains higher measurement resolution and stability, effectively reducing measurement errors caused by external environmental factors and ensuring the reliability of data output in practical applications.

2. Ultra-Low Power Consumption

 It features ultra-low power consumption design, with a typical operating power of only 0.8 W. This low power consumption characteristic not only significantly extends the service life of the power supply (especially for battery-powered equipment) but also reduces heat generation during operation, avoiding performance degradation caused by overheating and improving the overall operational stability of the product.

3. Compact and Lightweight Design

The product adopts a lightweight and small-size structural design, which greatly reduces the space occupation and overall weight of the equipment it is mounted on. This advantage is particularly critical for applications with strict requirements on installation space and load capacity, such as small unmanned aerial vehicles, portable measurement equipment, and compact industrial devices, facilitating flexible installation and reducing the burden on the carrier.

 4. Ultra-Fast Start-Up Speed

 With an ultra-fast start-up response, the product can complete the start-up process and enter the stable working state in as short as 0.02 seconds. This rapid start-up capability ensures that the product can quickly respond to operational needs, reducing the waiting time for system deployment and improving the efficiency of equipment operation, especially in scenarios requiring real-time and rapid measurement.

 5. Ultra-Wide Bandwidth

 It is equipped with an ultra-wide bandwidth of up to 1 kHz, enabling it to accurately capture and respond to high-frequency dynamic signals. This wide bandwidth characteristic allows the product to adapt to complex dynamic working environments, effectively ensuring the accuracy and real-time performance of data measurement even when the measured object undergoes rapid changes in motion state.

 6. High Reliability and Impact Resistance

The product has excellent reliability and strong impact resistance, which is realized through strict structural design and high-quality material selection. It can maintain stable performance under harsh working conditions such as vibration, impact, and extreme temperature changes, reducing the failure rate during long-term operation and ensuring the continuity and stability of the system, making it suitable for harsh industrial and aerospace application scenarios.

 1. Aerospace Field

 In the aerospace field, open loop FOGs are mainly applied to low-precision flight control systems of small and medium-sized aircraft, unmanned aerial vehicles (UAVs), and aerospace models, leveraging their fast start-up speed and stable data output to provide key support for attitude control and trajectory adjustment.

 For small UAVs (including consumer-grade and industrial-grade), open loop FOGs are integrated into the flight control system to measure the angular rate of the UAV relative to inertial space in real time. This data is used to adjust the rotation of the propeller and the deflection of the control surface, ensuring the UAV's stable flight, hover, and trajectory tracking-especially suitable for scenarios such as aerial photography, agricultural plant protection, and power line inspection, where high-precision inertial measurement is not required but cost and reliability are prioritized.

 In addition, open loop FOGs are also used in aerospace models and small satellites, providing basic angular rate measurement data for attitude stabilization, helping the equipment maintain a stable posture during flight or orbit operation, and reducing the dependence on high-cost closed-loop FOGs to control the overall development and application costs.

 2. Industrial Control Field

 The industrial control field is one of the core application scenarios of open loop FOGs, which are widely used in servo control systems, mechanical equipment positioning, and turntable stability control, relying on their low power consumption and compact design to adapt to the narrow installation space of industrial equipment.

  In industrial servo systems (such as mechanical arms, numerical control machine tools, and conveyor systems), open loop FOGs provide real-time rotational angular rate feedback for the servo controller. The controller adjusts the output torque and speed according to the feedback data, reducing mechanical vibration and positioning errors, and improving the stability and control accuracy of the servo system. For example, in the rotation control of mechanical arms, the open loop FOG can accurately measure the rotation speed of the arm joint, ensuring smooth and precise movement of the mechanical arm during loading, unloading, and assembly operations.

 In addition, open loop FOGs are also used in the stability control of industrial turntables (such as test turntables and radar turntables), which can quickly respond to the rotation changes of the turntable and provide real-time angular rate data, ensuring that the turntable maintains a stable rotation speed and posture, and improving the accuracy of test and detection work.

 3. Marine Navigation Field

 In the marine navigation field, open loop FOGs are mainly applied to small and medium-sized ships, marine buoys, and underwater robots, providing basic inertial navigation support for their navigation and positioning, especially suitable for scenarios where satellite navigation signals are weak or unavailable.

 For small and medium-sized ships (such as fishing boats, yachts, and coastal transport ships), open loop FOGs are integrated into the ship's navigation system to measure the ship's angular rate of rotation in real time, assisting the compass and satellite navigation system to correct the ship's course, avoid deviation, and ensure safe navigation in coastal waters or inland rivers. Compared with traditional mechanical gyroscopes, open loop FOGs have the advantages of no mechanical wear, long service life, and low maintenance cost, which are more in line with the practical needs of small and medium-sized ships.

In underwater robots (such as shallow-water detection robots and underwater operation robots), open loop FOGs provide attitude control data for the robot, helping it maintain a stable posture during underwater movement, accurately complete detection, sampling, and other operations, and adapt to the complex underwater working environment.

1. Superior Performance That Exceeds Industry Standards

Our open loop FOG is engineered to deliver exceptional performance that meets and exceeds industry benchmarks for its class. It boasts the highest sensitivity and measurement accuracy in its size category, ensuring stable and reliable data output even in complex working environments. With an ultra-fast start-up time of only 0.02 seconds, it can quickly enter a stable working state, reducing system deployment waiting time and improving operational efficiency. Additionally, the product features an ultra-wide 1kHz bandwidth, enabling it to accurately capture high-frequency dynamic signals and adapt to rapid changes in the motion state of the measured object.

Unlike ordinary open loop FOGs on the market, our product adopts advanced optical path design and signal processing technology, effectively reducing measurement errors caused by temperature drift, vibration, and electromagnetic interference, ensuring long-term measurement stability and consistency.

2. Ultra-Low Power Consumption & Compact Lightweight Design

We fully consider the practical application needs of various equipment, and the product is designed with ultra-low power consumption and compact lightweight characteristics. With a typical operating power of only 0.8 W, it significantly reduces energy consumption, extends the service life of the power supply (especially for battery-powered equipment such as UAVs and portable measurement devices), and reduces heat generation during operation to avoid performance degradation caused by overheating.

The compact and lightweight structural design greatly reduces the space occupation and overall weight of the mounted equipment, making it ideal for scenarios with strict requirements on installation space and load capacity-such as small UAVs, compact industrial servo systems, and underwater robots. Its flexible installation method also simplifies the integration process, reducing the difficulty and cost of system integration.

3. High Reliability & Strong Environmental Adaptability

Reliability is the core requirement of inertial measurement equipment, and our open loop FOG is built to be highly reliable and durable. We use high-quality optical components and rugged structural materials, and undergo strict environmental testing (including high and low temperature, humidity, vibration, and impact tests) to ensure that the product can maintain stable performance in harsh working conditions (-40℃ to 85℃ operating temperature range, strong electromagnetic interference, and high impact environment).

With no mechanical wear and tear (unlike traditional mechanical gyroscopes), the product has a long service life and low maintenance costs, reducing the frequency of equipment replacement and maintenance, and ensuring the continuity and stability of your system operation.

4. Cost-Effective Solution for Low-to-Medium Precision Needs

For most low-to-medium precision inertial measurement and control scenarios (such as small UAV flight control, industrial servo control, and small ship navigation), high-cost closed-loop FOGs are often unnecessary. Our open loop FOG provides a cost-effective solution that balances performance and cost-while ensuring stable and reliable performance, it significantly reduces the overall procurement and application costs, helping you control project budgets without compromising quality.

We also provide flexible customization services, which can adjust product parameters (such as measurement range, output interface, and structural size) according to your specific application needs, ensuring that the product perfectly matches your system requirements.

5. Professional Technical Support & Perfect After-Sales Service

Choosing our open loop FOG means you will receive comprehensive professional support. Our team of experienced engineers provides one-on-one technical consultation, helping you solve problems encountered in product selection, integration, and use. We also offer timely after-sales service, including product maintenance, repair, and technical training, ensuring that your equipment operates stably for a long time.

1. Light Emission and Splitting: The light source emits a stable monochromatic light beam, which is incident on the beam splitter/coupler. The coupler splits the light beam into two equal-intensity beams, one propagating clockwise (CW) and the other counterclockwise (CCW) along the fiber loop.

2. Propagation in the Fiber Loop: When the FOG is stationary (no rotation), the two counter-propagating light beams travel the same path length in the fiber loop, so they have no phase difference when they recombine at the coupler.

3. Phase Difference Generation: When the FOG and its carrier rotate around the sensitive axis (the axis perpendicular to the plane of the fiber loop), the fiber loop rotates synchronously. The CW light beam travels a longer path (in the direction of rotation), while the CCW light beam travels a shorter path (opposite to the rotation direction), resulting in a phase difference between the two beams, which is proportional to the angular rate of rotation.

4. Signal Detection and Conversion: The two light beams with phase difference are recombined by the coupler and incident on the photodetector. The photodetector converts the interference signal (intensity change caused by phase difference) into an electrical signal. The signal processing circuit amplifies, filters, and demodulates this electrical signal, extracts the phase difference information, and converts it into a digital or analog angular rate signal that can be used by the external system (such as a flight control system or servo control system).

Q1: What is the difference between open loop FOG and closed loop FOG in terms of measurement accuracy?

A1: Generally, the measurement accuracy of open loop FOG is lower than that of closed loop FOG. Closed loop FOG adopts a feedback control mechanism to compensate for the phase difference generated by the Sagnac effect, which can effectively reduce measurement errors caused by external interference (such as temperature drift and light source fluctuation). Open loop FOG directly detects the phase difference without feedback compensation, so its accuracy is relatively limited, which is suitable for low-to-medium precision application scenarios. However, open loop FOG has advantages of simpler structure, lower power consumption and cost.

Q2: Is open loop FOG suitable for battery-powered equipment?

A2: Very suitable. The open loop FOG adopts an ultra-low power consumption design, with a typical operating power of only 0.8 W, which is much lower than that of closed loop FOG. This low power consumption characteristic can significantly extend the service life of the battery, making it ideal for battery-powered equipment such as small UAVs, portable measurement devices and underwater robots.

Q3: What is the service life of the open loop FOG?

A3: The service life of the open loop FOG is usually more than 10,000 hours under normal use and maintenance conditions. Since it has no mechanical moving parts, there is no mechanical wear, which is much longer than that of traditional mechanical gyroscopes. The service life will be affected by factors such as operating environment, maintenance level and usage intensity. Proper maintenance can effectively extend the service life.

Q4: Can the open loop FOG be calibrated? How to calibrate it?

A4: Yes, the open loop FOG can be calibrated to improve measurement accuracy. Calibration is usually carried out by using a standard turntable, which rotates the FOG at a known angular rate, compares the output signal of the FOG with the standard angular rate, and adjusts the parameters of the signal processing circuit to reduce measurement errors. It is recommended to calibrate the FOG regularly (such as once every 6 months to 1 year) according to the usage scenario. For specific calibration methods, please refer to the product manual or contact our technical support team.

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