GB2234877A

GB2234877A - Determining orientation of pilot's helmet for weapon aiming

Info

Publication number: GB2234877A
Application number: GB8918184A
Authority: GB
Inventors: Keith Herbert Hoskins
Original assignee: GEC Marconi Ltd; Marconi Co Ltd
Current assignee: BAE Systems Electronics Ltd
Priority date: 1989-08-09
Filing date: 1989-08-09
Publication date: 1991-02-13
Also published as: GB8918184D0

Abstract

It is desirable for a pilot in an aircraft to be able to quickly aim weaponry at an enemy target. This may be achieved by determining the direction in which the pilot is looking by the orientation of his helmet. A pattern is provided on the helmet which is viewed by an imaging system e.g. two CCD cameras mounted behind the pilot. The cameras output data to a micro processor which is able to recognise the pattern and provide information as to the position and orientation of the helmet. <IMAGE>

Description

Automatic Locating System This invention relates to an automatic locating system and more specifically, but not exclusively, to a system used to locate a helmet worn by a pilot.

It is desirable when flying fighter aircraft to be able to quickly aim at a target. One way in which this has been achieved is to arrange that weaponry mounted on the aircraft follows the direction of glance of the pilot.

This has previously been achieved by mounting magnetic devices on or within the helmet of the pilot and measuring the effect these magnetic devices have upon the overall magnetic field within the cockpit of the aircraft. The magnetic field of the cockpit is known when empty and therefore any variation in the magnetic field of the cockpit when the pilot is inside with the magnetic devices fixed to his helmet then gives an indication of the direction of glance of the pilot. A ca3culation computes the approximate orientation and position of the pilot's helmet. This information is then passed to a servo which orientates weaponry accordingly.

The system not only suffers from the drawback of the pilot having to wear a helmet which is heavier than its usual weight, because of the magnetic devices within it, but also the system may be prone to interference from electro-magnetic surges within the vicinity of the aircraft. The present invention overcomes these problems by providing an improved locator system.

According to the present invention apparatus to ascertain the direction in which a helmet is pointing, the helmet having an identifying feature on it, comprises an imager to provide data representative of the identifying feature, means to store information about the identifying feature and means to ascertain the direction in which the helmet is pointing from the stored and imaged data.

Preferably the identifying feature is a pattern on the pilot's helmet which will enable the imager to derive sufficient information as to the position and the orientation of the helmet by calculation of the deviation of identifying features from a known datum. This may also be achieved by having different patterns or 3D shapes attached to the helmet.

Preferably the imager provides data and this data is compared with a plurality of data stores, each store representing a different orientation of the pilots head.

The instantaneous position of the pilot's head is then found by sequentially comparing the instantaneous data, obtained from the imager, with stored data of a plurality of different possible positions in which the helmet may be. The nearest version of stored data is then used to provide an indication of the direction of glance of the pilot.

Preferably there are two cameras spaced either side of the pilot's straight ahead line of viewing.

Two ways in which the invention may be performed will now be described by way of example with reference to the drawings in which: Figure 1 illustrates a diagramatical view of the interior of an aircraft cockpit; Figure 2 illustrates a plan view of the same helicopter cockpit; Figure 3 illustrates a representation of a rear view of the pilot's helmet as viewed by two CCD cameras; and Figure 4 illustrates rear view of a variety of pilot's helmets.

Referring to figure 1 the pilot 1 sits in a cockpit 2 wearing a helmet 3. CCD cameras 4 and 5 are mounted 300 left and 300 right of the line of the pilot's usual head-on gaze. The cameras 4 and 5 are connected to a processor 6 via lines L4 and L5 respectively. The processor 6 is also connected to a store 7 of data and to a servo 8, upon which servo is mounted a cannon 9. The servo is positioned outside the cockpit The pilot is wearing the helmet 3 with a pattern 30 painted on the back, facing the cameras 4 and 5. The pattern 30 is depicted in detail in figure 4d. The two different views as seen by cameras 4 and 5 are seen in figure 3a and 3b respectively. The pilot is glancing to the left.

Spots P', Q' and R' on the back of the helmet 3 are recognised by the processor 6 as being in a particular position in space, namely, that position which is depicted in Figures 3c and 3d. Figure 3c illustrates a grid 50 representing the image seen by camera 5, the gr-id 51 in figure 3d representing the image seen by camera 5. These grids 50 and 51 represent pixels which are activated in the 512 x 512 CCD arrays within cameras 4 and 5 respectively.

The position in which the spots would be, as viewed by cameras 4 and 5 when the pilot is glancing straight ahead, is denoted by the points P, Q and R on grid 50 and 51. These points correspond to spots P1, Q1 and R1 on the helmet 3. The actual positions of the spots P1, Q1 and R1 when the pilot is glancing to the left as viewed by the cameras 4 and 5 are depicted by the spots P', Q' and R' on the grids, and these are slightly displaced from the spots P, Q and R.

The Horizontal deviation ss x of P from P' and vertical deviation A y of P from P' as viewed by camera 5, is used in conjunction with the same deviations of Q from Q' and of R from R' to compute the orientation of the helmet in space. A similar computation is effected for the right hand camera 4. The two images when combined enable the position and orientation of the helmet to be unambiguously pin-pointed in space. The processor is able to recognise that in certain positions a camera may not be able to see all three dots P, Q and R. Artificial intelligence is able to determine which dots are being viewed when the images from the two cameras are compared in the processor. Information about the angle of azimuth and rotation is then sent to the servo 8.

A second way in which the invention may be performed is to sequentially compare the viewed image or images with stored information about a plurality of fixed images. The processor selects the nearest image and orientates the weaponry 9 accordingly.

In Figure 4, some examples of patterns are illustrated which would be capable of enabling the orientation and position of the helmet 3 to be found by its distinctive elements. Figure 4a depicts a helmet which has parallel non equi-spaced vertical and horizontal 3ines. Figure 4b has pattern of concentric circles painted on it. Figure 4c has a pattern of parallel lines which cross over and they are neither horizontal nor vertical the lines having different thicknesses. Figure 4d has three distinct dots printed on the helmet which are at the apices of an equilateral triangle. Figure 4e has five fins 60 attached to it at different positions around the helmet and figure 4f has three different sized dots at the apices of an equilateral triangle.

Of course modifications to the system may be made without departing from the scope of the invention; for example a horizontal and a vertical polariser may be fitted to each of the cameras 4 and 5 so as to detect the horizontal and vertical lines. An alternate embodiment would be to have different coloured lines or shapes on the helmet and different colour filters on the two cameras so that the cameras may only detect one type of colour shape or line and thus enable the helmet to be located.

Claims

1. Apparatus to ascertain the direction in which a helmet is pointing, the helmet having an identifying feature on it, the apparatus comprising an imager to provide data representative of the identifying feature, means to store information about the identifying feature and means to ascertain the direction in which the helmet is pointing from the stored information and image data.

2. Apparatus according to claim 1 wherein data representative of the identifying feature is compared with a series of data corresponding to known directions so as to ascertain the direction in which the helmet is pointing.

3. Apparatus according to claim 1 wherein the direction in which the helmet is pointing is ascertained from the data representative of the identifying feature by way of a series of calculations of deviations of observed positions of features from a datum.

4. Apparatus according to any preceding claim wherein the identifying feature is a pattern on the helmet.

5. Apparatus according to claim 4 wherein the pattern comprises a plurality of non equi-spaced parallel lines.

6. Apparatus according to claim 4 wherein the pattern comprises three dots which are at the apices of an equilateral triangle.

7. Apparatus according to any preceding claim wherein the imager is a CCD camera.

8. Apparatus according to any one of claims 1 - 6 wherein the imager comprises two CCD cameras.

9. Apparatus substantially as herein described and with reference to the Figures.