# US 8,570,211 B1 · Aircraft bird strike avoidance method and apparatus

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- Number: US 8,570,211 B1
- Document ID: US8570211B1
- Status: Granted
- Kind: B1
- Application number: 12/657,318
- Filed: 2010-01-19
- Granted: 2013-10-29
- Earliest claimed: 2009-01-22
- Applicants: Gregory Hubert Piesinger
- Inventors: Gregory Hubert Piesinger
- Web page: https://patentgrep.com/patent/US8570211B1

## CPC

- G01S 13/284: {using coded pulses}
- G01S 7/415: {Identification of targets based on measurements of movement associated with the target}
- G01S 13/003: {Bistatic radar systems; Multistatic radar systems}
- G01S 13/48: using multiple beams at emission or reception
- G01S 13/933: of aircraft or spacecraft
- G01S 2013/468: {by Triangulation, i.e. two antennas or two sensors determine separately the bearing, direction or angle to a target, whereby with the knowledge of the baseline length, the position data of the target is determined}
- 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 non-scanning radar system is installed on an aircraft to detect and avoid bird strikes or collisions with other airborne hazards. Target amplitude, range, and Doppler tracking versus time are used to qualify the collision threat. Avoidance is based on a quick minor altitude change by the pilot or autopilot to exit the imminent bird or other airborne hazard altitude window. In one embodiment, a bistatic passive radar receiver antenna is used in conjunction with an existing geostationary satellite signal. Range and Doppler information are obtained via cross correlation processing of the hazard reflection signal with a direct path reference signal from the satellite.

## Claims

### Claim 1

A method for detecting and avoiding an aircraft collision with birds, said method comprising:
providing at least one non-scanning antenna on said aircraft;
illuminating a surveillance volume ahead of said aircraft with a radar signal;
receiving reflections of said radar signal from radar targets at least as small as birds in said surveillance volume, said receiving operation being performed by the same or a different one of said at least one non-scanning antenna on said aircraft;
measuring target parameters of said radar targets, said target parameters include at least range, amplitude, and Doppler shift of each said radar targets;
determining the collision threat probability of said aircraft with said radar targets, said collision threat probability determined by the variation of said target parameters with time;
alerting the pilot of a collision threat when said collision threat probability exceeds a predetermined threshold; and
maneuvering said aircraft to avoid colliding with said birds when alerted of said collision threat, said maneuvering operation being performed by said pilot or an aircraft autopilot.

### Claim 2 (depends on 1)

A method as claimed in claim 1 wherein said collision threat probability exceeds said predetermined threshold when a target normalized said amplitude is nearly constant as said range to said target decreases.

### Claim 3 (depends on 1)

A method as claimed in claim 1 wherein said collision threat probability exceeds said predetermined threshold when a target said Doppler shift is nearly constant as said range to said target decreases.

### Claim 4 (depends on 1)

A method as claimed in claim 1 wherein said radar signal is transmitted and said reflections are received using the same or different said non-scanning antenna on said aircraft.

### Claim 5 (depends on 1)

A method as claimed in claim 1 wherein said radar signal is transmitted from a geostationary satellite and said reflections are received using at least one said non-scanning antenna on said aircraft.

### Claim 6 (depends on 5)

A method as claimed in claim 5 wherein said geostationary satellite is at least one XM satellite radio geostationary satellite.

### Claim 7 (depends on 5)

A method as claimed in claim 5 wherein said geostationary satellite is at least one Fixed Satellite Services or Broadcasting Satellite Services geostationary communications satellite.

### Claim 8 (depends on 5)

A method as claimed in claim 5 wherein said radar signal is an existing broadcast signal from said geostationary satellite.

### Claim 9 (depends on 1)

A method as claimed in claim 1 wherein said radar signal is a continuous wave pseudo random noise coded pulse compression waveform.

### Claim 10 (depends on 1)

A method as claimed in claim 1 further including receiving a non-reflected said radar signal and cross correlating said non-reflected radar signal with a reflected said radar signal from a target to measure said target parameters.

### Claim 11 (depends on 1)

A method as claimed in claim 1 further including separating a pair of said non-scanning antenna on said aircraft horizontally or vertically and determining said collision threat probability of said radar targets by triangulation.

### Claim 12

An apparatus for detecting and avoiding an aircraft collision with birds, said apparatus comprising:
one or more non-scanning antennas mounted on said aircraft and configured to observe an airborne surveillance volume ahead of said aircraft;
a transmitter configured to illuminate said surveillance volume with a radar signal;
receivers coupled to each said antennas and configured to receive reflections of said radar signal from radar targets at least as small as birds;
a signal detection processor coupled to said receivers and configured to detect and process said reflections from said radar targets;
a target processor coupled to said signal detection processor and configured to determine if said radar targets represents a collision threat between said aircraft and said birds; and
means for communicating said collision threat to said aircraft pilot or said aircraft autopilot,
whereby said pilot or said autopilot can maneuver said aircraft to avoid a collision with said birds.

### Claim 13 (depends on 12)

An apparatus as in claim 12 wherein said signal detection processor includes a plurality of filters matched to different Doppler offset frequencies of said reflections of said radar signal from said radar targets.

### Claim 14 (depends on 12)

An apparatus as in claim 12 wherein said signal detection processor includes a signal detector configured to measure target parameters of said radar targets, said target parameters include at least range, amplitude, and Doppler shift of each said radar targets.

### Claim 15 (depends on 12)

An apparatus as in claim 12 wherein a target is determined to be said collision threat when the normalized said target amplitude is essentially constant as said target range to said target decreases.

### Claim 16 (depends on 12)

An apparatus as in claim 12 wherein a target is determined to be said collision threat when said target Doppler shift is essentially constant as said target range to said target decreases.

### Claim 17 (depends on 12)

An apparatus as in claim 12 wherein said transmitter is located on a geostationary satellite.

### Claim 18 (depends on 17)

An apparatus as in claim 17 wherein said radar signal is said geostationary satellite existing broadcast signal.