Long-range, small target rangefinding

Patent metadata

Field	Value
Publication number	US-2016011313-A1
Application number	US-201314436766-A
Country	US
Kind code	A1
Filing date	Oct 18, 2013
Priority date	Oct 18, 2012
Publication date	Jan 14, 2016
Grant date	—

Abstract

A device for measuring a distance of a target by means of a telemeter comprises: a laser pulse emitter; a receiver of the laser echoes backscattered by the target, comprising, a spatial detection device which comprises at least one photodiode set up as integrator and is able to provide a spatial signal, and a temporal detection device which comprises at least one photodiode coupled to a transimpedance circuit and is able to provide a so-called temporal signal, means of processing of the spatial signal and of the temporal signal, comprising a unit for calculating the distance of the target, the temporal signal being in the form of a data frame which is the recording of data detected over a predetermined duration. The means of processing comprise: means of post-integration of temporal signals, linked at output to the unit for calculating the distance of the target, linked to the spatial detection device and to the temporal detection device, means for selecting the temporal signals to be transmitted to the post-integration means, as a function of the spatial signal.

First claim

1 . A device for measuring a distance of a target by means of a telemeter comprising:
a laser pulse emitter, a receiver of the laser echoes backscattered by the target, comprising:
a spatial detection device which comprises at least one photodiode set up as integrator and is able to provide a so-called spatial signal, and
a temporal detection device which comprises at least one photodiode coupled to a transimpedance circuit and is able to provide a so-called temporal signal,
means of processing of the spatial signal and of the temporal signal, comprising a unit for calculating the distance of the target, the temporal signal being in the form of a data frame which is the recording of data detected over a predetermined duration, wherein the means of processing comprise:
means of post-integration of temporal signals, linked at output to the unit for calculating the distance of the target,
linked to the spatial detection device and to the temporal detection device, means for selecting the temporal signals to be transmitted to the post-integration means, as a function of the spatial signal.

2 . The device as claimed in claim 1 , in which the means for selecting the temporal signals comprise a switching control linked at output to the temporal detection device via a switch and linked at input to the spatial detection device and able to switch the temporal detection device via the switch as a function of the spatial signal, and in that the post-integration means are linked at input to the temporal detection device.

3 . The device as claimed in claim 1 , in which the switching control is furthermore linked to the post-integration means.

4 . The device as claimed in claim 1 , in which the means for selecting the temporal signals are discrimination means linked at input to the spatial detection device and to the temporal detection device and at output to the post-integration means.

5 . The device as claimed in claim 1 , in which the means of processing comprise means of temporal labeling of the frames.

6 . The device as claimed in claim 1 , in which the emitter has a direction of emission and the receiver has a direction of reception and furthermore comprises a device for aligning the direction of emission and the direction of reception.

7 . The device as claimed in claim 1 , in which the laser pulse emitter comprises means for adapting the divergence and for collimating the laser beam at infinity.

8 . The device as claimed in claim 1 , further comprising means for detecting a presence of a target for distances less than the minimum telemetry distance, the detecting means being adapted for deactivating the operation of the laser emission and for ensuring the ocular safety of the device from the zero distance.

9 . The device as claimed in claim 1 , further comprising means for orienting the telemetry axis.

10 . The device as claimed in claim 1 , further comprising means for measuring deviometry between the telemetry axis and the position of the target, the measuring means being connected to the spatial detector.

11 . A method for measuring the distance of a target by means of a telemeter as claimed in claim 1 , comprising:
a spatial detection step comprising a sub-step of emission of a laser pulse by the emission device, a sub-step of detecting the spatial signal SS and of acquiring a value I of integration of SS, a temporal detection step comprising a sub-step of emission of laser pulses by the emission device, and a sub-step of acquiring a temporal signal ST in the form of data frames, a step of post-integration of the data frames ST as a function of the spatial signal SS, when the result of the post-integration is above a threshold, a step of calculating the distance.

12 . The method for measuring the distance of a target as claimed in the preceding claim by means of a telemeter as claimed in claim 2 comprising the following sequential steps:
a spatial detection step comprising a sub-step of emission of a laser pulse by the emission device, a sub-step of detecting the spatial signal SS corresponding to the laser echo of said pulse and of acquiring a value I of integration of SS, and when the value I is below a predetermined threshold S 1 , the previous step is repeated,
otherwise a target then having been detected, a temporal detection step is implemented comprising a sub-step of emission of other laser pulses by the emission device, and a sub-step of acquiring a temporal signal ST in the form of data frames, corresponding to the laser echoes of these other pulses,
a step of post-integration of the data frames ST obtained during the temporal detection step.

13 . The method for measuring the distance of a target as claimed in the preceding claim by means of a telemeter as claimed in claim 3 comprising the following sequential steps:
a step of 1st spatial detection comprising a sub-step of emission of a laser pulse by the emission device, a sub-step of detecting the spatial signal SS corresponding to the laser echo of said pulse and of acquiring a value I of integration of SS, and when the value I is below a predetermined threshold S 1 , the previous sub-steps are repeated,
otherwise a target then having been detected, a temporal detection step is implemented comprising a sub-step of emission of other laser pulses by the emission device, and a sub-step of acquiring a temporal signal ST in the form of data frames termed group A of frames, corresponding to the laser echoes of these other pulses,
a step of post-integration of this group A of data frames ST obtained during the temporal detection step,
a temporal detection step is implemented comprising a sub-step of emission of other laser pulses by the emission device, which differ from those of the group A, a sub-step of acquiring a temporal signal ST in the form of data frames termed group B of frames, corresponding to the laser echoes of these other pulses, and a sub-step of placing this group B of frames in memory,
a step of 2nd spatial detection comprising a sub-step of emission of a laser pulse by the emission device, a sub-step of detecting the spatial signal SS corresponding to the laser echo of said pulse and of acquiring a value I of integration of SS, when the value I is above a predetermined threshold S 1 , the spatial detection being confirmed, a step of post-integration of the group B of data frames,
and then acquisition of a new group A of frames,
and when the value I is below a predetermined threshold S 1 , the cycle resumes at the level of the first spatial detection.

14 . The method for measuring the distance of a target as claimed in claim 11 by means of the telemeter comprising:
a laser pulse emitter,
a receiver of the laser echoes backscattered by the target, comprising:
a spatial detection device which comprises at least one photodiode set up as integrator and is able to provide a so-called spatial signal, and
a temporal detection device which comprises at least one photodiode coupled to a transimpedance circuit and is able to provide a so-called temporal signal,

means of processing of the spatial signal and of the temporal signal, comprising a unit for calculating the distance of the target, the temporal signal being in the form of a data frame which is the recording of data detected over a predetermined duration,
wherein the means of processing comprise:
means of post-integration of temporal signals, linked at output to the unit for calculating the distance of the target,
linked to the spatial detection device and to the temporal detection device, means for selecting the temporal signals to be transmitted to the post-integratio

Assignees

• Thales Sa

Inventors

• Rousseau Pascal

Classifications

• G01S7/4816

  of receivers alone · CPC title

• G01S17/66 Primary

  Tracking systems using electromagnetic waves other than radio waves · CPC title

• G01S17/08

  for measuring distance only (indirect measurement G01S17/46; active triangulation systems G01S17/48) · CPC title

• G01S7/4873

  by deriving and controlling a threshold value · CPC title

• G01S7/481 Primary

  Constructional features, e.g. arrangements of optical elements · CPC title