For field applications such as hand-held observation or rifle sights, and for large quantities, image intensifiers are still preferred to thermal cameras because they are cheaper. Even where cost is not an issue, traditional thermal cameras with cooled detectors have negative aspects. They are large, heavy, noisy and difficult to maintain because of their cryogenic-cooled detectors, scanning mirrors and optical systems. Further disadvantages are that cool-down time is a severe handicap for soldiers in action and their bulky size, shape and weight often prove impractical in operational use.
For hand-held applications, these factors have limited their deployment, resulting in a requirement for thermal-imaging technology able to provide good performance and low weight at reduced cost.
| Production of the LION hand-held binocular is planned for 1997 |
Now these criteria can be met by thermal-imaging systems based on large pyroelectric detector arrays that operate without the need for cooling and view infra-red scenes directly without complex opto-mechanical scanning systems. In Europe, uncooled thermal detector technology was achieved by the UK Defence Research Agency and GEC Marconi programme that resulted in the availability of uncooled detector arrays and associated electronics.
In parallel, a Dutch consortium consisting of Delft Sensor Systems of the Delft Instruments group and Signaal Usfa of Thomson-CSF, has developed a hand-held binocular observation sight called LION (lightweight infrared observation night), as the first application for the British modules. This Dutch-government supported development was initiated by a Dutch army requirement for 700 thermal binoculars.
Evaluation trials are planned for the end of 1996 and production to begin in 1997.
The world-wide marketing and sales of this European product will be shared by Delft Sensor Systems, Signaal Usfa, Thomson-CSF and GEC Marconi Sensors.
LION sight is a true thermal camera designed for use by infantry as a hand-held binocular. The camera is based on the 256 x 128 pyro-electric focal plane array detector operating in the eight to 12µm atmospheric window. The LION camera features microscanning technology that almost doubles the spatial resolution of the detector and eliminates image break-up in moving scenes.
Innovative technologies used include a diffractive single-field infrared objective; a microscanned uncooled focal plane detector; fully integrated signal-processing electronics including automatic contrast and brightness control; a lightweight non-metal housing and a display system that provides the image to both eyes. The LION provides exceptional performance with excellent image quality during day and night, through smoke, mist and fog.
Measuring 20 x 22 x 10cm, the camera fits easily into the user's hands and weighs less than 2kg including internal batteries that give 10 hours operational use. Operating on standard C-type cells it accepts lithium, rechargeable nicad and alkaline batteries. A rapid switch-on time of about five seconds means a power-consuming stand-by mode is avoided.
Operation is simple and because the camera is inaudible and unlike cooled systems cannot be detected by its cold-spot signature, the user remains undetectable. The LION has a 10O field-of-view, three-fold magnification and a NETD of 0.1OC. Detection, recognition and identification ranges are 2,300m, 800m and 400m (STANAG). Environmental performance conforms to military standards.
In addition to its primary use as a hand-held camera, LION can be remote controlled and/ or powered and provides a CCIR video output for external use. Options include a remote control-display-supply unit and a power adaptor for a 24-volt vehicle battery supply.
A high MTBF (5,000 hours), minimal maintenance and the use of rechargeable batteries for training purposes, mean the LION has low life-cycle costs compared to conventional cooled thermal cameras.
