# US 11,307,303 B2 · Ground control point device and SAR displacement measuring system

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- Number: US 11,307,303 B2
- Document ID: US11307303B2
- Status: Granted
- Kind: B2
- Application number: 16/590,432
- Filed: 2019-10-02
- Published: 2020-04-09
- Granted: 2022-04-19
- Earliest claimed: 2018-10-03
- Assignees: NEC Corporation
- Applicants: NEC Corporation
- Inventors: Tsunekazu Kimura
- Web page: https://patentgrep.com/patent/US11307303B2

## CPC

- G01S 13/9011: {with frequency domain processing of the SAR signals in azimuth (G01S13/9005 takes precedence)}
- G01S 7/025: {involving the transmission of linearly polarised waves}
- G01S 7/40: Means for monitoring or calibrating
- G01S 7/411: {Identification of targets based on measurements of radar reflectivity (G01S7/415 takes precedence)}
- G01S 13/9023: {combined with interferometric techniques}
- G01S 13/9076: {Polarimetric features in SAR}
- G01S 19/07: providing data for correcting measured positioning data, e.g. DGPS [differential GPS] or ionosphere corrections
- H01Q 15/18: comprising plurality of mutually inclined plane surfaces, e.g. corner reflector {(H01Q15/16 takes precedence)}
- G01S 13/003: {Bistatic radar systems; Multistatic radar systems}
- G01S 19/14: specially adapted for specific applications
- 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
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)

## Abstract

A ground control point device includes an SAR wave reflector configured to receive an SAR wave incident from an SAR in an incident direction and to reflect the SAR wave in the incident direction; a GNSS receiver configured to receive a GNSS wave to generate, based on the GNSS wave, time information and positional information indicative of a position of a control point; an SAR wave receiver configured to receive the SAR wave; and a control point data generator/transmitter configured to generate control point data obtained by associating the positional information when the SAR receiver receives the SAR wave with a time instant of reception of the SAR wave that is determined based on the time information, and to transmit the control point data to outside.

## Claims

### Claim 1

A ground control point device installed at a control point of a synthetic aperture radar (SAR) displacement measuring system which performs an SAR analysis, the ground control point device comprising:
an SAR wave reflector configured to receive an SAR wave incident from an SAR in an incident direction and to reflect the SAR wave in the incident direction;
a global navigation satellite system (GNSS) receiver configured to receive a GNSS wave to generate, based on the GNSS wave, time information and positional information indicative of a position of the control point;
an SAR wave receiver configured to receive the SAR wave; and
a control point data generator/transmitter configured to generate control point data obtained by associating the positional information when the SAR receiver receives the SAR wave with a time instant of reception of the SAR wave that is determined based on the time information, and to transmit the control point data to outside.

### Claim 2 (depends on 1)

The ground control point device according to claim 1,
wherein the ground control point device is assigned with a control point ID unique to the ground control point device, and
wherein the control point data also includes the control point ID.

### Claim 3 (depends on 1)

The ground control point device according to claim 1,
wherein the SAR wave reflector includes a plurality of corner reflectors, and
wherein the plurality of corner reflectors are arranged at equiangular intervals from one another around a vertical line extending towards a zenith, and open laterally and towards the zenith.

### Claim 4 (depends on 2)

The ground control point device according to claim 2,
wherein the SAR wave reflector includes a plurality of corner reflectors, and
wherein the plurality of corner reflectors are arranged at equiangular intervals from one another around a vertical line extending towards a zenith, and open laterally and towards the zenith.

### Claim 5 (depends on 1)

The ground control point device according to claim 1,
wherein the SAR wave receiver includes an SAR antenna configured to receive the SAR wave, and
wherein at least a part of the SAR antenna is constructed using a part of the SAR wave reflector.

### Claim 6 (depends on 2)

The ground control point device according to claim 2,
wherein the SAR wave receiver includes an SAR antenna configured to receive the SAR wave, and
wherein at least a part of the SAR antenna is constructed using a part of the SAR wave reflector.

### Claim 7 (depends on 3)

The ground control point device according to claim 3,
wherein the SAR wave receiver includes an SAR antenna configured to receive the SAR wave, and
wherein at least a part of the SAR antenna is constructed using a part of the SAR wave reflector.

### Claim 8 (depends on 4)

The ground control point device according to claim 4,
wherein the SAR wave receiver includes an SAR antenna configured to receive the SAR wave, and
wherein at least a part of the SAR antenna is constructed using a part of the SAR wave reflector.

### Claim 9 (depends on 1)

The ground control point device according to claim 1, further comprising a radome which is made of a material allowing the SAR wave to be transmitted therethrough and which covers a top portion and a side portion of the SAR wave reflector,
wherein the SAR wave receiver includes an SAR antenna which is mounted in the radome and which is configured to receive the SAR wave, and
wherein the GNSS receiver includes a GNSS antenna which is installed outside the radome and which is configured to receive the GNSS wave.

### Claim 10 (depends on 2)

The ground control point device according to claim 2, further comprising a radome which is made of a material allowing the SAR wave to be transmitted therethrough and which covers a top portion and a side portion of the SAR wave reflector,
wherein the SAR wave receiver includes an SAR antenna which is mounted in the radome and which is configured to receive the SAR wave, and
wherein the GNSS receiver includes a GNSS antenna which is installed outside the radome and which is configured to receive the GNSS wave.

### Claim 11 (depends on 3)

The ground control point device according to claim 3, further comprising a radome which is made of a material allowing the SAR wave to be transmitted therethrough and which covers a top portion and a side portion of the SAR wave reflector,
wherein the SAR wave receiver includes an SAR antenna which is mounted in the radome and which is configured to receive the SAR wave, and
wherein the GNSS receiver includes a GNSS antenna which is installed outside the radome and which is configured to receive the GNSS wave.

### Claim 12 (depends on 4)

The ground control point device according to claim 4, further comprising a radome which is made of a material allowing the SAR wave to be transmitted therethrough and which covers a top portion and a side portion of the SAR wave reflector,
wherein the SAR wave receiver includes an SAR antenna which is mounted in the radome and which is configured to receive the SAR wave, and
wherein the GNSS receiver includes a GNSS antenna which is installed outside the radome and which is configured to receive the GNSS wave.

### Claim 13 (depends on 5)

The ground control point device according to claim 5, further comprising a radome which is made of a material allowing the SAR wave to be transmitted therethrough and which covers a top portion and a side portion of the SAR wave reflector,
wherein the SAR wave receiver includes an SAR antenna which is mounted in the radome and which is configured to receive the SAR wave, and
wherein the GNSS receiver includes a GNSS antenna which is installed outside the radome and which is configured to receive the GNSS wave.

### Claim 14 (depends on 6)

The ground control point device according to claim 6, further comprising a radome which is made of a material allowing the SAR wave to be transmitted therethrough and which covers a top portion and a side portion of the SAR wave reflector,
wherein the SAR wave receiver includes an SAR antenna which is mounted in the radome and which is configured to receive the SAR wave, and
wherein the GNSS receiver includes a GNSS antenna which is installed outside the radome and which is configured to receive the GNSS wave.

### Claim 15 (depends on 7)

The ground control point device according to claim 7, further comprising a radome which is made of a material allowing the SAR wave to be transmitted therethrough and which covers a top portion and a side portion of the SAR wave reflector,
wherein the SAR wave receiver includes an SAR antenna which is mounted in the radome and which is configured to receive the SAR wave, and
wherein the GNSS receiver includes a GNSS antenna which is installed outside the radome and which is configured to receive the GNSS wave.

### Claim 16 (depends on 8)

The ground control point device according to claim 8, further comprising a radome which is made of a material allowing the SAR wave to be transmitted therethrough and which covers a top portion and a side portion of the SAR wave reflector,
wherein the SAR wave receiver includes an SAR antenna which is mounted in the radome and which is configured to receive the SAR wave, and
wherein the GNSS receiver includes a GNSS antenna which is installed outside the radome and which is configured to receive the GNSS wave.

### Claim 17 (depends on 1)

A synthetic aperture radar (SAR) displacement measuring system, comprising:
an SAR which is installed in a flying object and which is configured to transmit an SAR wave to an observation area on the surface of the earth, to receive a reflected wave of the SAR wave, to generate SAR observation data obtained by associating image information based on the received reflected wave with a time instant of reception of the reflected wave of the SAR wave and an observation area ID unique to the observation area at the time instant of reception, and to transmit the SAR observation data toward the ground;
the ground control point device according to claim 1;
a ground station configured to receive the SAR observation data transmitted from the SAR and to transmit the SAR observation data to outside; and
a geodetic information processing device configured to match the SAR observation data transmitted from the ground station and the control point data transmitted from the ground control point device with each other on the basis of the respective time instants of reception, the observation area ID, and the control point ID, and to conduct an SAR analysis based on the SAR observation data and the control point data matched with each other.

### Claim 18 (depends on 2)

A synthetic aperture radar (SAR) displacement measuring system, comprising:
an SAR which is installed in a flying object and which is configured to transmit an SAR wave to an observation area on the surface of the earth, to receive a reflected wave of the SAR wave, to generate SAR observation data obtained by associating image information based on the received reflected wave with a time instant of reception of the reflected wave of the SAR wave and an observation area ID unique to the observation area at the time instant of reception, and to transmit the SAR observation data toward the ground;
the ground control point device according to claim 2;
a ground station configured to receive the SAR observation data transmitted from the SAR and to transmit the SAR observation data to outside; and
a geodetic information processing device configured to match the SAR observation data transmitted from the ground station and the control point data transmitted from the ground control point device with each other on the basis of the respective time instants of reception, the observation area ID, and the control point ID, and to conduct an SAR analysis based on the SAR observation data and the control point data matched with each other.

### Claim 19 (depends on 3)

A synthetic aperture radar (SAR) displacement measuring system, comprising:
an SAR which is installed in a flying object and which is configured to transmit an SAR wave to an observation area on the surface of the earth, to receive a reflected wave of the SAR wave, to generate SAR observation data obtained by associating image information based on the received reflected wave with a time instant of reception of the reflected wave of the SAR wave and an observation area ID unique to the observation area at the time instant of reception, and to transmit the SAR observation data toward the ground;
the ground control point device according to claim 3;
a ground station configured to receive the SAR observation data transmitted from the SAR and to transmit the SAR observation data to outside; and
a geodetic information processing device configured to match the SAR observation data transmitted from the ground station and the control point data transmitted from the ground control point device with each other on the basis of the respective time instants of reception, the observation area ID, and the control point ID, and to conduct an SAR analysis based on the SAR observation data and the control point data matched with each other.

### Claim 20 (depends on 17)

The SAR displacement measuring system according to claim 17, wherein the geodetic information processing device includes a pre-analysis data storage unit configured to temporarily store the SAR observation data transmitted from the ground station and the control point data transmitted from the ground control point device before carrying out matching between the SAR observation data and the control point data.