# US 7,612,711 B1 · System and method for communicating low data rate information with a radar system

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- Number: US 7,612,711 B1
- Document ID: US7612711B1
- Status: Granted
- Kind: B1
- Application number: 12/436,311
- Filed: 2009-05-06
- Granted: 2009-11-03
- Earliest claimed: 2005-11-03
- Assignees: L-3 Communications Corporation
- Inventors: William K. McIntire; Larry S. Thomson; David H. Robbins; James J. Boesch
- Web page: https://patentgrep.com/patent/US7612711B1

## CPC

- G01S 7/006: {using shared front-end circuitry, e.g. antennas (G01S13/765, G01S13/825 take precedence)}
- G01S 13/90: using synthetic aperture techniques {, e.g. synthetic aperture radar [SAR] techniques}
- 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

A method is disclosed for transmitting low data rate symbols from a communications terminal to a burst radar transceiver. A plurality of bursts can be emitted from a burst radar transceiver, each burst having a burst interval and separated by an inter-burst interval. A symbol can be transmitted from the communications terminal to the burst radar transceiver. The symbol has a symbol period that is substantially longer than a radar transceiver burst period comprising the burst interval and the inter-burst interval. Symbol energy can be accumulated during inter-burst intervals at the burst radar transceiver over a plurality of burst periods for approximately the symbol period.

## Claims

### Claim 1

A method for receiving low data rate symbols, the symbols having information encoded therein, the symbols being received at a burst radar transceiver having a burst period including a burst interval and an inter-burst interval, comprising:
accepting the symbol sections at the burst radar transceiver;
blanking a radar receiver during the burst interval to reduce interference between a radar transmitter and a radar receiver in the burst radar transceiver;
accumulating symbol energy at the burst radar transceiver during inter-burst intervals over a plurality of burst periods for approximately a symbol period of the low data rate symbols; and
identifying the information in the symbol based on a characteristic of the accumulated symbol energy.

### Claim 2

A system for transmitting low data rate symbols to a burst radar transceiver having a burst period including a burst interval and an inter-burst interval, comprising:
a communications terminal configured to transmit a plurality of symbols to the burst radar transceiver, wherein each symbol has a symbol transmission period that is substantially longer than the radar transceiver burst period;
a blanking device coupled to the burst radar transceiver configured to substantially attenuate a received signal during the burst radar transceiver burst interval; and
an integrating device configured to accumulate symbol energy at the burst radar transceiver over a plurality of burst periods during inter-burst intervals.

### Claim 3 (depends on 2)

A system as in claim 2, wherein the communications terminal includes a transmitter and a receiver.

### Claim 4 (depends on 2)

A system as in claim 2, wherein the burst radar transceiver includes a transmitter and a receiver.

### Claim 5 (depends on 4)

A system as in claim 4, wherein the blanking device is configured to attenuate a signal to the receiver using at least one of a physical switch and an electronic switch.

### Claim 6 (depends on 4)

A system as in claim 4, wherein the blanking device is configured to substantially eliminate digital data received during a burst interval.

### Claim 7 (depends on 4)

A system as in claim 4, wherein the receiver is configured to identify information in the symbol based on a characteristic of the accumulated symbol energy.

### Claim 8 (depends on 4)

A system as in claim 4, further comprising a phase memory configured to enable the receiver to ensure, at an end of a first burst period of the received signal, a correct phase at a beginning of a second burst period separated from the first burst period by the inter-burst interval.

### Claim 9 (depends on 2)

A system as in claim 2, wherein the symbol period is greater than one burst period.

### Claim 10 (depends on 2)

A system as in claim 2, wherein the symbol period is greater than ten burst periods.

### Claim 11 (depends on 2)

A system as in claim 2, wherein the plurality of symbols are encoded using forward error correction coding.