Topic
Gyrocompass
About: Gyrocompass is a research topic. Over the lifetime, 468 publications have been published within this topic receiving 3250 citations.
Papers published on a yearly basis
1 / 2
Papers
1 Oct 1990
TL;DR: A magnetic compass is often used to determine direction with respect to magnetic north, correction for the magnetic declination giving true north, more during magnetic storms as discussed by the authors, but care has to be exercised that no local iron or electric currents distort the magnetic field.
Abstract: DIRECTION DETERMINATION The three degrees of freedom, latitude, longitude, and elevation (or equivalents), constitute a rectangular coordinate system (neglecting earth curvature effects), and clearly determination of the orientations of the axes is important. The vertical direction is usually defined by means of a level or plumb line. Horizontal orientation can be determined with respect to the position of a celestial body, the Earth's rotation, magnetic north, or a previously known orientation. Although the most obvious celestial orientation is by sighting on Polaris (which is not exactly at the celestial pole), any star can be used. Sighting on the Sun ( sun shots ) permits orientation during daylight. Nightime observations can establish orientation to a fraction of an arc second (arcsec). Gyrocompass orientation is extensively used in marine and airborne surveys. A gyrocompass gives orientation with respect to true north within about 20 arcsec. A magnetic compass is often used to determine direction with respect to magnetic north, correction for the magnetic declination giving true north. Diurnal variations may create 10 min of error, more during magnetic storms. Care has to be exercised that no local iron or electric currents distort the magnetic field. Benchmarks (identified points of known location) often have nearby reference points (azimuth bars) that can be used to establish orientation. DISTANCE MEASUREMENT Direct measurement of distance is done by seeing how many times a standard measure will fit between points whose separation is to be determined, a technique called chaining , the unit of measure usually being a steel tape (a chain ) of precise length.
158 citations
TL;DR: This paper investigates the possibility of training a neural network to behave in the same manner as an optimal ship guidance system, the objective being to provide a system that can adapt its parameters so that it provides optimal performance over a range of conditions, without incurring a large computational penalty.
Abstract: Many conventional ship autopilots use proportional integral and derivative (PID) control algorithms to guide a ship on a fixed heading (course-keeping) or a new heading (course-changing). Such systems usually have a gyrocompass as a single sensory input. Modern sea going vessels have a range of navigation aids most of which may be interconnected to form integrated systems. It is possible to employ the navigational data to provide best estimates of state vectors (Kalman filter) and optimal guidance strategies. Such techniques require powerful computing facilities, particularly if the dynamic characteristics of the vessel are changing, as may be the case in a maneuvering situation or changes in forward speed. This paper investigates the possibility of training a neural network to behave in the same manner as an optimal ship guidance system, the objective being to provide a system that can adapt its parameters so that it provides optimal performance over a range of conditions, without incurring a large computational penalty. A series of simulation studies have been undertaken to compare the performance of a trained neural network with that of the original optimal guidance system over a range of forward speeds. It is demonstrated that a single network has comparable performance to a set of optimal guidance control laws, each computed for different forward speeds. >
90 citations
Patent•
31 Dec 1980TL;DR: In this article, a marine cable positioning system consisting of a plurality of magnetic compasses and lateral positioning devices spaced at known intervals along the cable being towed by a marine vessel is described.
Abstract: A marine cable positioning system which includes a plurality of magnetic compasses and a plurality of lateral positioning devices spaced at known intervals along the cable being towed by a marine vessel Readings from the compasses together with readings from a magnetic compass and gyrocompass onboard the towing vessel are gathered and used with a selected reference heading to generate X-Y coordinates of the lateral positioning devices with respect to the towing vessel and selected reference heading These coordinates are recorded and provided to a cathode ray tube for visual display of the relative position of each lateral positioning device with respect to the vessel and selected heading Coded digital commands are generated and transmitted to each lateral positioning device for adjustment of its control surfaces whereby the lateral thrust produced the device as it is towed through the water is varied and the horizontal position of the portion of the cable to either side of the device controlled Feedback of changes in the cable's location are provided by updated compass readings and visual displays Each lateral positioning device responds to a command for a specific adjustment of its control surfaces or for the return of the control surfaces to a neutral orientation where lateral thrust is not produced
86 citations
Book•
1 Aug 1971
TL;DR: Sperry as mentioned in this paper was a major American inventor who obtained more than 350 patents during his lifetime and contributed greatly to the technological changes occurring between 1880 and 1930, and his inventions included arc-light systems, mining machinery, electric automobiles and streetcars, and electrochemical processes.
Abstract: This is a biography of a major American inventor, who obtained more than 350 patents during his lifetime. Elmer Sperry contributed greatly to the technological changes occurring between 1880 and 1930. He was best known for the Sperry gyrocompass and automatic pilot, and his inventions included arc-light systems, mining machinery, electric automobiles and streetcars, and electrochemical processes. Characteristic of his various inventions were feedback controls which have made automation a fact of life. The book won the Dexter Prize of the Society for the History of Technology.
76 citations
4 May 2010
TL;DR: In this paper, the authors report progress toward a MEMS gyroscope suitable for northfinding in pointing and targeting applications, achieving in-run bias stability of 0.03 deg/hr and ARW of0.002 deg/rt(hr).
Abstract: We report progress toward a MEMS gyroscope suitable for northfinding in pointing and targeting applications. In-run bias stability of 0.03 deg/hr and ARW of 0.002 deg/rt(hr) have been achieved. Gyro performance was measured on tuning-fork type MEMS gyroscopes using DSP-based breadboard electronics. These bias stability and ARW results are within about 6X and 2X, respectively, of meeting the typical gyrocompass requirements for pointing and targeting applications (1 milliradian azimuth precision at 65 degrees latitude with 5 minute integration time). A MEMS gyrocompass meeting these requirements would substantially reduce the size, weight and power of pointing and targeting instruments. The test methodology will be presented, as well as test data on carouseling the sensor to reduce the effects of long-term bias drift.
67 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 8 |
| 2020 | 12 |
| 2019 | 9 |
| 2018 | 18 |
| 2017 | 16 |
| 2016 | 13 |