Search results

This study aims to design an optimized algorithm for low-cost pedestrian navigation system (PNS) to correct the heading drift and altitude error, thus achieving high-precise pedestrian location in both two-dimensional (2-D) and three-dimensional (3-D) space.

A novel heading correction algorithm based on smoothing filter at the terminal of zero velocity interval (ZVI) is proposed in the paper. This algorithm adopts the magnetic sensor to calculate all the heading angles in the ZVI and then applies a smoothing filter to obtain the optimal heading angle. Furthermore, heading correction is executed at the terminal moment of ZVI. Meanwhile, an altitude correction algorithm based on step height constraint is proposed to suppress the altitude channel divergence of strapdown inertial navigation system by using the step height as the measurement of the Kalman filter.

The verification experiments were carried out in 2-D and 3-D space to evaluate the performance of the proposed pedestrian navigation algorithm. The results show that the heading drift and altitude error were well corrected. Meanwhile, the path calculated by the novel algorithm has a higher match degree with the reference trajectory, and the positioning errors of the 2-D and 3-D trajectories are both less than 0.5 per cent.

Besides zero velocity update, another two problems, namely, heading drift and altitude error in the PNS, are solved, which ensures the high positioning precision of pedestrian in indoor and outdoor environments.

The Vanguard range of transformers has recently been announced by the Small Transformer Division of Grcsham Transformers Ltd., Hanworth Trading Estate, Feltham, Middlesex, and was shown for the first time at the 1961 Radio and Electronic Components Exhibition.

This paper aims to improve shearer positioning accuracy. Shearer positioning using an inertial navigation system (INS) is a highly useful technology; however, positioning accuracy is seriously hindered by INS attitude error, particularly heading drift.

A shearer positioning model with double-INS based on extended Kalman filter was proposed. The constant distance between two INSs (INS 1 and INS 2) was selected as the observation vector. Allan variance was used to identify the noise type of the vertical-axis gyroscope, and the stochastic process of heading drift for two INSs was obtained and divided into incongruous drift and concurrent drift.

Simulation was then carried out to determine the optimal arrangement of the two INSs. For incongruous drift, the optimal arrangement satisfied the condition that the line connecting INS 1 and INS 2 was perpendicular to the shearer lateral axis (in the shearer coordinate frame) and parallel to the east-north plane (in the east-north-up coordinate frame). Under optimal arrangement, the positioning accuracy increased against the distance between INS 1 and INS 2. For concurrent drift, the double-INS positioning model had no effect. Under the circumstances, the number of INSs should be increased so that the uncertainty of INS drift was reflected as much as possible.

A new double-INS positioning model was proposed with the constant distance between the two INSs. The optimal arrangement for double-INS was obtained.

THE Trident has been designed from the outset for the eventual introduction of completely automatic landing.

This paper presents the results of a heading estimation method for a remotely operated vehicle (ROV). The output rate of commercially available underwater compasses is typically in the order of a few Hz. Heading frequencies of at least 1 KHz are desirable for navigation and control purposes.

The estimation was performed by fusioning the signals of three inertial sensors: the ROV’s own underwater compass (which operates roughly at 10 Hz or less), the ROV’s embedded gyro and an additional angular rate sensor that provides readings from 1 to 3 KHz. The output signal of the additional angular rate sensor is not part of the proposed Kalman filter. Nonetheless a five-point Newton-Cotes closed integration of such signal is fed into the Kalman filter implementation that performs the required heading estimation at 1 KHz or more.

The proposed Kalman filter implementation is a suitable approach to estimate heading position even though the original compass signal rate is significantly slower than the signal required for both assisted and autonomous control.

The estimated heading yield good results in both simulation and experimental environments.

The method was embedded in a dedicated 16-bit DSP that handles both the acquisition of the three signals and the heading estimation, hence resulting in a very low-cost solution. The embedded solution was tested in the developed submarine and the obtained high-rate heading parameter is now used by the control system of the ROV.

IN covering British activities in the inertial guidance field, it is appropriate to include a brief picture of developments in the historical sense so that British achievements can be seen in perspective especially with regard to the state‐of‐the‐art in the United States. We will also deal with the application of inertial navigation systems to the civil field for, although at the moment every production inertial quality system in service is being operated in a military rôle, civil aviation is on the threshold of adopting inertial techniques.

This paper aims to present a method for improving the performance of the visual-inertial navigation system (VINS) by using a bio-inspired polarized light compass.

The measurement model of each sensor module is derived, and a robust stochastic cloning extended Kalman filter (RSC-EKF) is implemented for data fusion. This fusion framework can not only handle multiple relative and absolute measurements, but can also deal with outliers, sensor outages of each measurement module.

The paper tests the approach on data sets acquired by a land vehicle moving in different environments and compares its performance against other methods. The results demonstrate the effectiveness of the proposed method for reducing the error growth of the VINS in the long run.

The main contribution of this paper lies in the design/implementation of the RSC-EKF for incorporating the homemade polarized light compass into visual-inertial navigation pipeline. The real-world tests in different environments demonstrate the effectiveness and feasibility of the proposed approach.

The Cossor C. R. 353 Meteorological Radar is one of eight similar equipments due for early delivery to the New Zealand mainland, Fiji, Raratonga and Funafuti. It has been designed and developed as a private venture by Cossor Radar & Electronics Ltd., The Pinnacles, Harlow, Essex, England, who have throughout paid close attention to the requirements and recommendations of Meteorological Authorities throughout the world.

THE FLIGHT GUIDANCE SYSTEM is largely digital and is expected to set the pattern for all future flight guidance system designs. The system actually consists of 3 systems integrated into one: automatic flight control system, central air data system and flight display and interface system. Although integrated for interface compatibility the 3 are here considered separately.

AFTER a 10‐hour direct flight a Boeing 707 had landed and clearance had been given to the stand. While the aircraft was travelling over a taxiway it was seen that a considerable quantity of unused fuel was being blasted rearwards by the jet efflux of No 1 engine. A ground operations vehicle driver also saw flames on the ground under the wing of the aircraft and informed the ground movements controller by radio who alerted the airport fire service. As the aircraft was turning to line up with the stand the captain called for No 1 and 4 engines to be shut down and later, for No 2 to be shut down. After the aircraft had halted he gave clearance for the emergency chutes to be disarmed and then continued with the normal shut down checks. Attention was however directed by someone outside to a ring of flames around the joint between thrust reverser cowling and the engine cowling of No 1 engine and flames also in the tail pipe area. Fire drill was immediately called for on No 1 engine.