# US 11,906,308 B2 · Optical unit for a projective optical metrological system for determining quantities relative to the asset and/or position and communicating data

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- Number: US 11,906,308 B2
- Document ID: US11906308B2
- Status: Granted
- Kind: B2
- Application number: 18/016,641
- Filed: 2021-07-15
- Published: 2023-09-14
- Granted: 2024-02-20
- Earliest claimed: 2020-07-17
- Assignees: Thales Alenia Space Italia S.p.A. Con Unico Socio; Scuola Superiore Di Studi Universitari E Perfezionamento Sant'Anna
- Applicants: Thales Alenia Space Italia S.p.A. Con Unico Socio; Scuola Superiore Di Studi Universitari E Perfezionamento Sant' Anna
- Inventors: Fulvio Bresciani; Valter Basso; Ernesto Ciaramella; Giulio Cossu; Mario Rannello
- Web page: https://patentgrep.com/patent/US11906308B2

## CPC

- G01C 21/025: {with the use of startrackers}
- H04B 10/118: specially adapted for satellite communication
- G01C 21/1656: {with passive imaging devices, e.g. cameras}
- G01S 5/16: using electromagnetic waves other than radio waves
- G01S 5/163: {Determination of attitude (using inertial means G01C9/00; control of attitude G05D1/49)}
- H04B 7/18519: {Operations control, administration or maintenance}
- G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S)
- H04B: TRANSMISSION
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES

## Abstract

Optical unit for a projective optical metrological system, which receives a light signal coming from a light constellation comprising a number of light sources; the optical unit includes: an optoelectronic image acquisition system and a first and a second optical circuit, which receive the light signal and are traversed by a first and a second optical beam, respectively. The first and the second optical circuits direct, respectively, at least a first part of the first optical beam and at least a first part of the second optical beam on the optoelectronic image acquisition system, so as to cause the simultaneous formation of two different images of the constellation in the optoelectronic image acquisition system. The optical unit further includes an electronic processing unit coupled to the optoelectronic image acquisition system, which determines a number of quantities indicative of the position and/or attitude of the light constellation with respect to the optical unit, based on the two images. The optical unit further includes an optical receiver and a derivation optical circuit configured to optically couple the optical receiver and at least one of the first and the second optical circuit, so that the optical receiver receives an optical information signal, which is a function of at least one of the first and the second optical beams. The optical receiver demodulates digital data from the optical information signal.

## Claims

### Claim 1

An optical unit for a projective optical metrological system (1), configured to receive a light signal (LS) coming from a light constellation (4) comprising a number of light sources (4A-4C), said optical unit (7; 107) comprising:
an optoelectronic image acquisition system (10; 110);
a first and a second optical circuit (OT1, OT2) configured to receive the light signal (LS) and to be traversed by a first and a second optical beam (R1,R2), respectively, the first and the second optical circuits (OT1, OT2) being further configured to direct, respectively, at least a first part (R1′) of the first optical beam (R1) and at least a first part (R2′) of the second optical beam (R2) on said optoelectronic image acquisition system (10; 110), so as to cause the simultaneous formation of two different images (I1, I2) of the constellation (4) in the optoelectronic image acquisition system (10; 110);
an electronic processing unit (40) coupled to the optoelectronic image acquisition system (10; 110) and configured to determine a number of quantities indicative of the position and/or attitude of the light constellation (4) with respect to the optical unit (7), based on said two images;
an optical receiver (30); and
a derivation optical circuit (16, 26) configured to optically couple the optical receiver (30) and at least one of the first and the second optical circuits (OT1, OT2), so that the optical receiver (30) receives an optical information signal (OIS), which is a function of at least one of the first and the second optical beams (R1, R2);
and wherein the optical receiver (30) is configured to demodulate digital data from the optical information signal (OIS).

### Claim 2 (depends on 1)

The optical unit according to claim 1, wherein the optical receiver (30) comprises:
a photodetector (32), optically coupled to said derivation optical circuit (16, 26) and configured to generate an electrical signal (ES) as a function of the optical information signal (OIS); and
a demodulation device (34), electrically coupled to the photodetector (32) and configured to extract said digital data from said electrical signal (ES).

### Claim 3 (depends on 1)

The optical unit according to claim 1, wherein the derivation optical circuit (16, 26) comprises an optical device (26) configured to focus the optical information signal (OIS) on the photodetector (32).

### Claim 4 (depends on 1)

The optical unit according to claim 1, wherein said demodulation device (34) is configured to perform a demodulation of the on-off keying type.

### Claim 5 (depends on 1)

The optical unit according to claim 1, wherein said derivation optical circuit (16, 26) comprises an additional optical beam divider (16), which is configured to receive at least the first optical beam (R1) and to divide the first optical beam (R1) into said respective first part (R1′), directed towards the optoelectronic image acquisition system (10; 110), and into a respective second part (R1″), directed towards the optical receiver (30).

### Claim 6 (depends on 5)

The optical unit according to claim 5, wherein said additional optical beam splitter (16) is configured so as to receive also the second optical beam (R2) and to divide the second optical beam (R2) into said respective first part (R2′), directed towards the optoelectronic image acquisition system (10), and into a respective second part (R2″), directed towards the optical receiver (30).

### Claim 7 (depends on 6)

The optical unit according to claim 6, wherein the optoelectronic image acquisition system (10) comprises a sensitive surface (A); and wherein the first and the second optical circuits (OT1, OT2) terminate on said sensitive surface (A), so that the two different images (I1, I2) of the constellation (4) are formed on the sensitive surface (A).

### Claim 8 (depends on 1)

The optical unit according to claim 1, wherein the first and the second optical circuits (OT1, OT2) share the same optical input (12), configured to receive the light signal (LS) coming from the light constellation (4).

### Claim 9 (depends on 8)

The optical unit according to claim 8, further comprising an input optical beam splitter (14), arranged downstream of the receiving optical element (12) and configured to divide the light signal (LS) into the first and the second optical beams (R1, R2).

### Claim 10 (depends on 1)

The optical unit according to claim 1, wherein the electronic processing unit (40) is configured to determine, for each of said two different images, a number of light intensity maxima equal to the number of light sources (4A-4C) of the light constellation (4), and to determine, on the basis of the determined positions of the light intensity maxima, said quantities indicative of the position and/or attitude of the light constellation (4) with respect to the optical unit (7).

### Claim 11 (depends on 1)

A projective optical metrological system (1) comprising:
the optical unit (7; 107) according to claim 1;
a transmission unit (2), which comprises the light constellation (4);
and wherein each light source (4A-4C) of the light constellation (4) is configured to generate a corresponding primary optical signal (POS1, POS2, POS3); and wherein the transmission unit (2) further comprises a modulation device (9) configured to modulate the primary optical signals (POS1, POS2, POS3) as a function of said digital data, so that the primary optical signals (POS1, POS2, POS3) are equal to each other.

### Claim 12 (depends on 11)

The metrological system according to claim 11, wherein the modulation device (9) is configured to implement an on-off keying modulation.

### Claim 13 (depends on 11)

The metrological system according to claim 11, wherein the light constellation (4) comprises a first, a second and a third light source (4A-4C), so that each image of said two different images is formed from a first, a second and a third image point (4A′, 4B′, 4C′; 4A″, 4B″, 4C″).

### Claim 14 (depends on 11)

A satellite system comprising a first and a second satellite (sat1, sat2) and a metrological system (1) according to claim 11, wherein the transmission unit (2) and the optical unit (7; 107) are bound to the first and the second satellites (sat1, sat2), respectively; and further comprising an attitude and/or position control system (150) bound to the second satellite (sat2) and configured to receive the quantities indicative of the position and/or attitude determined by the electronic processing unit (40) and/or said digital data.