News: Product News
7th June 2016
Explore New Dimensions at the National Space Centre: Spectrum Metrology will be hosting an Open Day this June in conjunction with Taylor Hobson and FARO. Register now ...
12th March 2019 • Read »
We are pleased to announce that the 4D InSpec XL surface defect gauge has won the 2019 Prism award in Test and Measurement. The award was presented to 4D Technology during the Photonics West 2019 expo by SPIE, the International Society for Optics and Photonics.
20th February 2019 • Read »
Autocollimators were used to align the optical components when the University of Leicester built the pioneering CompAQS scanner in collaboration with Surrey Satellite Technology and DL Optics Ltd
18th October 2018 • Read »
Spectrum Metrology invites visitors to the MACH exhibition to witness the optical clarity and precision of their latest digital projectors and video microscopes, manufactured by German designers Dr Schneider Messtechnik.
6th March 2018 • Read »
Shipbuilders and marine engineers Cammell Laird are using the Micro Alignment Telescope to assist with precise alignment of the ships propeller shafts to the marine engine during build of the Sir David Attenborough polar research vessel
26th January 2018 • Read »
Static Alignment of ships weapon systems using precision electronic tilt measurement system
Static alignment of weapons platforms is of critical importance to achieving weapons accuracy. A warships structure will bend and flex over the course of its lifetime. Exposure to rough seas, variations in temperature and changes in loading cause varying stress on the ships frame; refits and accidents cause even more permanent changes. All of this precipitates variations in the accuracy and precision of the alignment of weapons relative to each other and to the physical configuration of the ship.
The fundamental method for finding static alignment errors is the tilt test or roller path test. This involves measuring the relative tilt between platforms at a series of places. When these individual errors are plotted against the bearings, a sine curve results which identifies the magnitude of tilt at the different positions on the vessel. To achieve the high performance demanded by modern weapon systems, these measurements have to be precise to within a few minutes of arc.
The conventional method of performing a tilt test was to use bubble clinometers (effectively bubble spirit levels) to measure the errors between platforms. This required that the ship be secured in dock for the duration of the measurements, with maintenance activities on board halted to minimise any movement. Even under these conditions, the ship could flex with the wind, causing movement of the clinometer and hindering measurement, meaning an engineer had to be present on each platform to adjust the level.
For a ship equipped with many weapons, the conventional method could take several days to complete and the cost of docking and downtime on the ship was substantial. Moreover, a docked ship experiences different stresses to those experienced when fully floating. Consequently, there was also uncertainty as to how much the structure would flex when released from dock and how much error would be re-introduced.
Using the CETAMS Electronic Tilt Measurement System allows precise measurement of tilt with no restrictions on movement of personnel or equipment, providing high accuracy measurement at a fraction of the cost of methods using bubble clinometers.
The measurement process for the tilt system is as follows: the ships Master Level Datum located on the ships founding plate acts as the reference platform and a sensor is placed on it, with the remaining sensors normally secured on the other platforms of the weapons system. This allows simultaneous measurement of all the ships platforms and calculation of the errors between them.
Tilt measurements are integrated and processed to effectively eliminate inaccuracies caused by the ships movement (rolling and pitching).
Accurate measurement of the tiny tilt differences between individual components allows mechanical compensation to be applied. More frequent correction factors can be entered into the ships fire control system and programmed to correct for them. This improves gun fire control and increases weapons accuracy. It is now possible to perform a test in under an hour.
Contact us for further information and to discuss your measurement application