Altitude-sensing device

Claim 3

The device specified in claim 1 in which the self-producing means includes a pair of photosensitive devices positioned to detect the reflected images from said half-silvered mirror and to be energized thereby.

Claim 4

The device specified in claim 2 including a masking means interposed between said pair of photosensitive devices and the half-silvered mirror, for masking the reflected images from the half-silvered mirror whereby said images are received by both of said photosensitive devices only at the critical distance.

Claim 5

The device specified in claim 3 including electrical circuit means operatively associated with said photosensitive devices for electrically signaling when both of said photosensitive devices are simultaneously energized. 5 A system for signaling critical altitude of a flight vehicle above a landing surface, said system comprising: means for projecting a beam of high intensity light; means for reflecting said light bean downwardly towards the landing surface, including means for splitting said high intensity beam into two beams which are reflected downwardly toward the landing surface in a fixed angular relation to each other so that they coalesce only at the critical altitude; and a pair of means for receiving images of the ground spots of illumination on the landing surface produced by said beams including light-responsive electrical circuit means associated with said receiving means for generating a usable voltage signal when the images of the ground spots of illumination are received by said receiving means at the critical altitude and displaying said spot images at only the critical altitude.

Claim 6

An altitude-sensing device for automatically signaling critical altitude of a flight vehicle above a landing surface, said device comprising: a light source; optical condenser and filter means for the light rays from said light source; means for dividing the light rays from said source which pass through said optical condenser means into two beams, said last mentioned means comprising a pair of spaced reflecting elements disposed in fixed positions to receive part of the light rays transmitted through said optical condenser and filter means and to reflect said rays downwardly towards the landing surface in a pair of beams in predetermined angular relationship; a half-silvered mirror interposed between said optical condenser and filter means and said reflecting elements in a position to transmit incident rays from said source and to reflect incident rays from said reflecting elements, said predetermined angular relationship of the beams being selected whereby images of the ground spots of illumination on the landing surface produced by said beams are formed in said half-silvered mirror in a predetermined range of altitudes including said critical altitude by reflection from the landing surface to said reflecting elements and from said reflecting elements to said half-silvered mirror; a pair of photosensitive devices; optical projection means for projecting said images from the half-silvered mirror to the photosensitive devices to energize the same; a masking means interposed between said pair of photosensitive devices and said optical projection means for masking said images reflected from the half-silvered mirror whereby said images are received by both of said photosensitive devices only at the critical altitude; and electrical circuit means operatively associated with said photosensitive devices for electrically signaling when both of said photosensitive devices are simultaneously energized.

Claim 7

An altitude-sensing device for automatically signaling critical altitude of a flight vehicle above a landing surface, said device comprising: a light source; optical condenser and filter means for the light rays from said light source; means for dividing the light rays from said source which pass through said optical condenser means into two beams, said last mentioned means comprising a pair of spaced reflecting elements disposed in fixed positions to receive part of the light rays transmitted through said optical condenser and filter means and to reflect said rays downwardly towards the landing surface in a pair of beams in predetermined angular relationship; a half-silvered mirror interposed between said optical condenser and filter means and said reflecting elements in a position to transmit incident rays from said source and to reflect incident rays from said reflecting elements, said predetermined angular relationship of the beams being selected whereby images of the ground spots of illumination on the landing surface produced by said beams are formed in said half-silvered mirror in a predetermined range of altitudes including said critical altitude by reflection from the landing surface to said reflecting elements and from said reflecting elements to said half-silvered mirror; a pair of photosensitive devices; optical projection means for projecting said images from the half-silvered mirror to the photosensitive devices to energize the same; a masking means interposed between said pair of photosensitive devices and said optical projection means for masking said images reflected from the half-silvered mirror whereby said images are received by both of said photosensitive devices only at the critical altitude; and electrical circuit means operatively associated with said photosensitive devices for electrically signaling when both of said photosensitive devices are simultaneously energized.