HDD technology breakthrough! North seeker helps with orientation in trenchless construction

 

As the core technology of trenchless pipeline laying, HDD technology places extremely high demands on the direction control of the drill bit. The precise control of the drilling trajectory depends on high-performance directional measurement equipment. With its unique technical advantages, the ER-MNS-09 north seeker has become a key equipment for improving construction efficiency and accuracy in HDD operations.

Core challenges and directional requirements of HDD construction

HDD construction requires the completion of pilot hole drilling, hole expansion, and pipeline pullback processes underground. Directional equipment needs to meet the requirements of narrow space adaptation, high-precision orientation, resistance to complex environmental interference and impact vibration, and adaptation to extreme working conditions.

ER-MNS-09’s technical advantages and HDD compatibility

**High-precision measurement to ensure trajectory control**

The azimuth accuracy can reach 0.25°, and the attitude accuracy is ≤0.2°. With a data update rate of 100Hz, it supports stable operation in the inclination range of -85~85°. The operator can adjust the drill bit trajectory in time based on the measurement data to meet the strict restrictions on trajectory deviation in HDD construction;

**Ultimately compact design, embedded in the core space of the probe tube**

The HDD guided probe pipe needs to be embedded in the front end of the drill pipe, and the size and weight of the equipment are limited. The ER-MNS-09 north seeker has a diameter of only 30mm, a length of 120mm, and a weight of ≤150g. It can be seamlessly integrated into the probe pipe or guide head at the front of the drilling equipment, and is suitable for mainstream drilling equipment.

**Autonomous north finding and anti-magnetic interference**

Adopting a high-precision MEMS gyroscope that can self-find north, the initial alignment is completed in 5 minutes, completely free from dependence on the geomagnetic field, and can stably output the true north azimuth, pitch angle and roll angle information in strong interference environments such as underground mines, metal pipelines or strong electromagnetic environments.

All-solid-state design: no mechanical rotating parts, excellent anti-impact and vibration ability, meeting the reliability requirements under severe vibration conditions during drilling.

**Wide temperature adaptability to cope with extreme working conditions**

Full temperature calibration compensation: The normal temperature version supports an operating temperature of 5~+55°C, and the high temperature version supports 5~125°C. It can withstand strong vibration and shock environments to ensure long-term reliability in deep wells, mud environments or high shock conditions.

more details: https://www.ericcointernational.com/north-finders/mems-triaxial-north-seeker-for-mining.html?utm_source=blogger&utm_medium=blog&utm_campaign=mining_north_seeker

Precise application of high-performance dynamic FOG north seeker in mining and oil exploration

 

The orientation accuracy of drilling equipment directly affects the efficiency and safety of logging drilling, tunnel excavation, and ore body positioning. During underground drilling operations, the vibration and attitude changes of the drilling rig are frequent, and traditional mechanical gyroscopes or magnetic compasses are difficult to work stably.

For more details: https://www.ericcointernational.com/north-finders/high-performance-dynamic-fog-north-seeker.html?utm_source=blogger&utm_medium=content&utm_campaign=north_seeker_blogger&utm_content=product_review_article

ER-FNS-01D high-performance dynamic FOG north seeker can achieve real-time accurate north seeking and attitude following in a vibrating environment. The north seeking accuracy can reach 0.5°, and the attitude measurement accuracy can reach 0.03° (1σ). Dynamic north-seeking technology can provide the true north direction of the carrier in real time. The working latitude of 65°N-65°S covers major mining areas and oil and gas fields around the world, ensuring that the drilling rig can still accurately control the drilling direction even when tilted or vibrating.

The compact size of 100×100×75mm and the lightweight design of 1kg make it easy to integrate into drilling equipment. Its core technical advantages are precisely targeted at complex working conditions:

Fast and precise dual modes: Supports 30-second fast alignment (azimuth accuracy 1°) and 90-second precise alignment (azimuth accuracy 0.5°), significantly shortening the equipment startup time. It can quickly establish the north reference after the drilling rig is in place. At the same time, its 20-minute accuracy retention capability allows the drilling rig to quickly resume operations after a short stop, reducing the time loss caused by repeated alignment.

Full environment adaptability: 5℃-55℃ full temperature range compensation technology adapts to the temperature difference between the deep mine and the field; there is humidity, dust and potential electromagnetic and metal interference in the mine, and the ER-FNS-01D is not affected by the magnetic field, which completely avoids the influence of the electromagnetic environment on the measurement results.

Strong vibration adaptability: The built-in shock absorber design can withstand 20Hz-2000Hz, 6.06g vibration environment, solving the problem of accuracy drift caused by vibration in dynamic operations of traditional north-seeking equipment.

New tools for drilling, well logging and mining, don’t you know about it yet?

 

In the fields of directional drilling, logging and mining, accurate control of direction and attitude is the core of successful operations. The complex industrial environment makes traditional sensors helpless. A new type of north seeker has become a tool for technological innovation with its unique advantages. Today we’ll take a closer look at why it’s essential for jobs in these fields.

**Break through space limitations: special-shaped design for easy installation**

Traditional inclinometers and MWD systems are installed at a certain distance from the drill bit, causing measurement errors; The cylindrical north seeker ER-MNS-09 adopts a compact design of 120mm × Φ30mm and weighs ≤150g. It can be directly embedded in the drilling rig's probe pipe and installed close to the drill bit.

This design is particularly suitable for oil logging tools (such as gyro tools, HDD tools) and TBM, significantly reducing measurement errors.

**Industry-leading accuracy: 0.25°secψ north-seeking accuracy**

In magnetic mining areas or deep well environments, magnetic field interference often leads to azimuth measurement deviations. The north seeker achieves true north orientation based on a three-axis MEMS gyroscope and accelerometer, with an accuracy of up to 0.25°secψ (1σ), far exceeding similar products on the market (generally 0.5°~1°secψ). The measurement error of the azimuth is controlled within a very small range.

Attitude tracking can be performed: output pitch, roll, and azimuth data to provide adjustment basis for drilling rigs or mining equipment. Initial attitude calibration and true north orientation are automatically completed in 5 minutes, greatly shortening the deployment time.

**A reliable partner in harsh environments: shock resistance, wide temperature range, and long battery life**

The operating environment of the oil and mining industry is extreme. The high-temperature version of the north seeker has an operating temperature of 5~125℃, which is suitable for high-temperature environments in deep wells; it can withstand strong shocks and vibrations during drilling to ensure continuous and stable data; it only requires 2W power and supports 6~12V wide voltage input, which is suitable for long-term continuous operation.

**Why choose a cylindrical north finder? **

Technological breakthrough: breaking the monopoly, the performance is comparable to that of a fiber optic gyroscope, and the cost is reduced;

Customized service: providing different accuracy and different temperature versions, normal temperature version (5~55℃) and high temperature version (5~125℃), to adapt to different operational needs;

For more data information, please discuss with me ：https://lnkd.in/eDyWMuWz

you can also take a screenshot and send it directly to this email address to ask : ericco188@ericcointernational.com

How does Tactical Fiber Optic Gyroscope Work？

 

Fiber optic gyroscope industry market

With its unique advantages, fiber optic gyroscope has a broad development prospect in the field of precision physical quantity measurement. Therefore, exploring the influence of optical devices and physical environment on the performance of fiber optic gyros and suppressing the relative intensity noise have become the key technologies to realize the high precision fiber optic gyro. With the deepening of research, the integrated fiber gyroscope with high precision and miniaturization will be greatly developed and applied.

Fiber optic gyroscope is one of the mainstream devices in the field of inertia technology at present. With the improvement of technical level, the application scale of fiber optic gyro will continue to expand. As the core component of fiber optic gyros, the market demand will also grow. At present, China's high-end optical fiber ring still needs to be imported, and under the general trend of domestic substitution, the core competitiveness of China's optical fiber ring enterprises and independent research and development capabilities still need to be further enhanced.

At present, the optical fiber ring is mainly used in the military field, but with the expansion of the application of optical fiber gyroscope to the civilian field, the application proportion of optical fiber ring in the civilian field will be further improved.

According to the "2022-2027 China Fiber Optic Gyroscope industry Market Survey and Investment Advice Analysis Report" :

The fiber optic gyroscope is a sensitive element based on the optical fiber coil, and the light emitted by the laser diode propagates along the optical fiber in two directions. The difference of light propagation path determines the angular displacement of the sensitive element. Modern fiber optic gyro is an instrument that can accurately determine the orientation of moving objects. It is an inertial navigation instrument widely used in modern aviation, navigation, aerospace and national defense industries. Its development is of great strategic significance to a country's industry, national defense and other high-tech development.
Fiber optic gyro is a new all-solid-state fiber optic sensor based on Sagnac effect. Fiber optic gyro can be divided into interferometric fiber optic gyros (I-FOG), resonant fiber optic gyro (R-FOG) and stimulated Brillouin scattering fiber optic gyro (B-FOG) according to its working mode. According to its accuracy, fiber optic gyro can be divided into: low-end tactical level, high-end tactical level, navigation level and precision level. Fiber optic gyroscopes can be divided into military and civilian according to their openness. At present, most fiber optic gyros are used in military aspects: fighter and missile attitude, tank navigation, submarine heading measurement, infantry fighting vehicles and other fields. Civil use is mainly automobile and aircraft navigation, bridge surveying, oil drilling and other fields.
Depending on the accuracy of the fiber optic gyroscope, its applications range from strategic weapons and equipment to commercial grade civilian fields. Medium and high-precision fiber optic gyroscopes are mainly used in high-end weapons and equipment fields such as aerospace, while low-cost, low-precision fiber optic gyroscopes are mainly used in oil exploration, agricultural aircraft attitude control, robots and many other civilian fields with low precision requirements. With the development of advanced microelectronics and optoelectronics technologies, such as photoelectric integration and the development of special fiber optics for fiber optic gyros, the miniaturization and low-cost of fiber optic gyros have been accelerated.

Summary

Ericco's fiber optic gyro is mainly a medium precision tactical fiber optic gyro, compared with other manufacturers, low cost, long service life, the price is very dominant, and the application field is also very wide, including two very hot selling ER-FOG-851, ER-FOG-910, you can click the details page for more technical data,

Tactical Grade Fiber Optic Gyro Comparison

If you have any purchase needs, feel free to send the inquiry, or contact us directly: Phone: +86-13992884879
Email: info@ericcointernational.com.

What is a tactical grade fiber optic gyro?

 

Ericco fiber optic gyro are mainly divided into tactical and navigation levels, and the accuracy of tactical fiber optic gyroscopes is generally 0.x-xº/h. Our tactical fiber-optic gyroscope is ER-FOG-50, https://www.ericcointernational.com/.../single-axis-fog... its accuracy is 0.2~2.0º/h, its size is very small, only Φ50mm×38mm, tactical fiber-optic gyroscope is mainly used in optical pods, missile seeker, UAV, small IMU, inertial navigation system, etc., the measurement range is -500~+500º/s. Both in terms of price and longevity, it will be your choice. If you want to get more technical data, please feel free to contact us at: info@ericcointernational.com. Phone: +86-13992884879

Why is it Called Fiber Optic Gyroscope?

 Like ring laser gyro, fiber optic gyro has the advantages of no mechanical moving parts, no preheating time, insensitive acceleration, wide dynamic range, digital output and small size. In addition, fiber optic gyro also overcomes the fatal shortcomings of ring laser gyro such as high cost and blocking phenomenon.

Fiber optic gyro is a kind of optical fiber sensor used in inertial navigation.
Because it has no moving parts - high-speed rotor, called solid state gyroscope. This new all-solid gyroscope will become the leading product in the future and has a wide range of development prospects and application prospects.

1. Fiber optic gyro classification

According to the working principle, fiber optic gyroscope can be divided into interferometric fiber optic gyro (I-FOG), resonant fiber optic gyro (R-FOG) and stimulated Brillouin scattering fiber optic gyroscope (B-FOG). At present, the most mature fiber optic gyro is the interferometric fiber optic gyroscope (that is, the first generation of fiber optic gyroscope), which is the most widely used. It uses multi-turn optical fiber coil to enhance SAGNAC effect. A double-beam ring interferometer composed of multi-turn single-mode optical fiber coil can provide high accuracy, but also will inevitably make the overall structure more complicated.
Fiber optic gyros are divided into open ring fiber optic gyroscopes and closed loop fiber optic gyros according to the type of loop. Open-loop fiber optic gyro without feedback, directly detect the optical output, save many complex optical and circuit structure, has the advantages of simple structure, cheap price, high reliability, low power consumption, the disadvantage is the input-output linearity is poor, small dynamic range, mainly used as an Angle sensor. The basic structure of an open-loop interferometric fiber optic gyro is a ring dual-beam interferometer. It is mainly used for occasions where the accuracy is not high and the volume is small.

2. Status and future of fiber optic gyroscope

With the rapid development of fiber optic gyro, many large companies, especially military equipment companies, have invested huge financial resources to study it. The main research companies for the United States, Japan, Germany, France, Italy, Russia, low and medium precision gyroscope has completed the industrialization, and the United States has maintained a leading position in this area of research.
The development of fiber optic gyroscope is still at a relatively backward level in our country. According to the level of development, the gyro development is divided into three echelons: the first echelon is the United States, the United Kingdom, France, they have all the gyro and inertial navigation research and development capabilities; The second tier is mainly Japan, Germany, Russia; China is currently in the third tier. The research of fiber optic gyro in China started relatively late, but with the efforts of the majority of scientific researchers, it has gradually narrowed the gap between us and the developed countries.
At present, China's fiber optic gyro industry chain is complete, and manufacturers can be found upstream and downstream of the industry chain, and the development accuracy of fiber optic gyro has reached the requirements of middle and low accuracy of inertial navigation system. Although the performance is relatively poor, it will not bottleneck like the chip.
The future development of fiber optic gyro will focus on the following aspects:
(1) High precision. Higher precision is an inevitable requirement for fiber optic gyro to replace laser gyro in advanced navigation. At present, the high precision fiber optic gyro technology is not fully mature.
(2) High stability and anti-interference. Long-term high stability is also one of the development directions of fiber optic gyroscope, which can maintain navigation accuracy for a long time under harsh environment is the requirement of inertial navigation system for gyroscope. For example, in the case of high temperature, strong earthquake, strong magnetic field, etc., the fiber optic gyro must also have sufficient accuracy to meet the requirements of users.
(3) Product diversification. It is necessary to develop products with different precision and different needs. Different users have different requirements for navigation accuracy, and the structure of the fiber optic gyro is simple, and only the length and diameter of the coil need to be adjusted when changing the accuracy. In this respect, it has the advantage of surpassing mechanical gyro and laser gyro, and its different precision products are easier to achieve, which is the inevitable requirement of the practical application of fiber optic gyro.
(4) Production scale. The reduction of cost is also one of the preconditions for fiber optic gyro to be accepted by users. The production scale of various components can effectively promote the reduction of production costs, especially for middle and low precision fiber optic gyro.

3.Summary

The accuracy of the fiber optic gyroscope ER-FOG-50 is 0.2~2.0º/h, and the accuracy of the ER-FOG-60 is 0.06~0.5º/h. Their application fields are basically the same, and can be used in small IMU, INS, missile seeker servo tracking, photoelectric pod, UAV and other application fields. If you want more technical data, please feel free to contact us.

Do You Know Minimum FOG IMU?

 

ER-FIMU-50 FOG IMU is a minimum cost-effective inertial measurement device for navigation, control and dynamic measurement. The system adopts high reliability closed-loop

hashtagfiber optic gyroscope and hashtagaccelerometer, and ensures the measurement accuracy through multiple compensation techniques.

Applications

hashtagAHRS
Guidance control system
Vehicle and ship attitude measurement
Inertial/satellite hashtagintegrated hashtagnavigation hashtagsystem
Drilling system
Mobile mapping system
Satellite communication in motion

Measurement Error and Calibration of FOG IMU

 

1. What causes FOG IMU measurement errors?

Inertial measurement unit is the core component of navigation information and heading attitude reference system, which determines the accuracy and environmental adaptability of the system. Fiber optic gyro is a kind of photoelectric inertial sensor based on Sagnac effect. It has the advantages of high precision, strong resistance to vibration and shock, fast start, etc. It is an ideal angular velocity sensor for rotorcraft, high performance navigation information and heading attitude measurement system. FOG's adaptability to temperature environment is poor, and the dynamic temperature environment in the working process of rotorcraft is harsh, which leads to the measurement error of FOG inertial measurement unit. It is necessary to study the precise calibration compensation method of FOG inertial measurement unit error to improve its environmental adaptability and measurement accuracy.

2. Calibration method 

Traditional IMU calibration methods include static multi-position calibration under normal temperature environment, angular rate calibration and hybrid calibration, etc. Among them, static multi-position calibration method can calibrate the error coefficient of IMU acceleration channel with high precision, but due to the small Earth rotation rate, The precision of the small FOG used in the high performance navigation information and heading attitude measurement system of the rotorcraft is similar to the earth rotation rate, resulting in low calibration accuracy of the error coefficient of the angular velocity channel. The error coefficient of FOG IMU angular velocity channel can be accurately calibrated by the traditional simple angular velocity calibration method, but the error coefficient of acceleration channel cannot be accurately calibrated. How to further reduce the calibration workload and improve the calibration accuracy is the key technology to be solved by FOG inertial measurement unit. In addition, parameters calibrated at room temperature will reduce FOG inertial measurement unit measurement accuracy if applied at high or low temperatures. Methods such as least squares fitting are often used to compensate the zero-bias or scale-factor temperature errors of inertial devices. Among them, the high-order least squares fitting compensation method can improve the system accuracy, but significantly increase the calculation amount of real-time compensation. The one-time fitting method has a small calculation amount, but it cannot meet the actual compensation accuracy requirements. Therefore, it is another key problem for FOG inertial measurement unit, a high performance and reliable navigation information and heading attitude measurement system of rotorcraft, to study the compensation method with small amount of computation and high precision.
Based on the FOG inertial measurement unit integrated error modeling in the high performance navigation information and heading attitude measurement system of rotorcraft, we calibrate and compensate the temperature and dynamic errors of the small low-precision FOG inertial measurement unit system, and propose a FOG inertial measurement unit full temperature tripartite positive and negative rate/position calibration method and piecewise linear interpolation compensation method for temperature errors. A tripartite positive and negative speed/one position calibration scheme is designed at each constant temperature point, and piecewise linear interpolation method is used to compensate the zero deviation of angular velocity channel, zero deviation of acceleration channel and scale factor temperature errors. The vehicle-mounted experiments show that the method can improve the system's environmental adaptability and measurement precision significantly, which lays a foundation for the further development of a small and high-performance fiber optic gyro IMU aircraft navigation information and heading attitude reference system.

3.FOG IMU deterministic error modeling

3.1 Angular velocity channel error model

FOG inertial measurement unit in rotorcraft, high performance navigation information and heading attitude measurement system consists of three fiber optic gyroscopes and accelerometers, IMU structure and data acquisition and preprocessing module. Three domestic small low-precision 11-FA fiber optic gyroscope sensitive carrier external input angular velocity, three GJ-27 quartz flexible accelerometers sensitive carrier external linear acceleration. FOG is insensitive to g and g2 terms. Considering the installation error, scale factor error and zero bias error of FOG IMU, the angular velocity channel error model of FOG inertial measurement unit in northeast sky coordinate system is established as

Where, i is the output angular velocity of FOG inertial measurement unit i axial gyro, and i is the input angular velocity of i axial gyro. i is zero deviation of i axis gyroscope; Ki is the scale factor of i axial gyroscope; Eij is the installation error coefficient of the angular velocity channel, and i and j are collectively referred to as the coordinate axes X, Y and Z.

3.2 Acceleration channel error model

FOG IMU acceleration channel error model is:

Where, ai is the output of FOG inertial measurement unit i axial addition, ai is the input of i axial addition,  i is zero deviation of i axial addition, Kai is the scale factor of i axial addition, Mij is the installation error coefficient of acceleration channel.

3.3 Full temperature tripartite positive/negative speed/one position calibration

The precision of inertial devices in FOG IMU is mainly related to external environment mechanics and temperature excitation. The operating environment temperature of rotorcraft varies greatly with the different seasons and flight altitudes. Due to the large random dynamic disturbance caused by wind gust and turbulence during successive flights, the influence of different temperatures and dynamic environment on FOG inertial measurement unit accuracy is mainly studied. The calibration temperature range, temperature point distribution density and calibration dynamic range are set according to the actual working environment and accuracy requirements of the system.
According to the mathematical model of system error, a FOG inertial measurement unit tripartite positive and negative rate/one position error calibration method is designed based on a temperature-controlled single-axis speed turntable without pointing north and a high-precision hexahedron tool. As shown in Figure 1, the hexahedron tooling is turned three times at each calibrated temperature point to ensure that the X, Y, and Z axes of FOG inertial measurement unit and the ZT axis of the turntable are reconnected respectively. According to the dynamic environment of the system, set the turntable in each direction to calibrate the positive and negative speed, and ensure that the rotation is above 360° at the speed point.

4. Full temperature piecewise linear interpolation compensation

In order to solve the problem of using FOG IMU in the navigation information and heading attitude measurement system of rotorcraft with high performance and small amount of computation and high precision error compensation, we use the segmented low-order linear interpolation method, dividing the interpolation interval into several cells, and using linear interpolation polynomial on each cell. It can be seen that the FOG inertial measurement unit angular velocity channel and acceleration channel zero bias, scale factor temperature error piecework linear interpolation compensation algorithm of rotor aircraft operating environment are between -10℃ and 40℃, so the calibration temperature points are set as -10℃, 5℃, 20℃, 30℃ and 40℃ respectively. The FOG inertial measurement unit is installed in the center of the hexahedron tool, and the X, Y and Z axes of the inertial navigation system are respectively parallel to the datum normal of the hexahedron tool through the high-precision positioning table. Then the hexahedral tooling is fixed horizontally on the plane of the temperature controlled single-axis rate turntable. The three-bit positive and negative speed/one-position calibration as shown in Figure 1 was realized by flipping the hexahedron tooling. Then change the temperature setting value, according to the above method, carry out the calibration experiment at -10℃, 5℃, 20℃, 30 ℃, 40 ℃ in turn.

5. Summary

FOG IMU is the core component of the navigation information and heading attitude reference system of small rotorcraft. ericco's ER-FIMU-50 and ER-FIMU-70, we can use full-temperature three-way positive and negative rate/one position calibration and PLI compensation method. According to the error characteristics of fiber optic gyro and quartz flexible accelerometer, the FOG inertial measurement unit error model is established, and the three-bit positive and negative rate/one-position calibration scheme is designed at each constant temperature point. The PLI algorithm is used to compensate the zero bias and scale factor temperature errors of the system in real time, reducing the calibration workload and the calculation amount of the compensation algorithm, and improving the system dynamics, temperature environment adaptability and measurement accuracy.