# US 10,871,574 B2 · Kinematics-augmented position validation

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- Number: US 10,871,574 B2
- Document ID: US10871574B2
- Status: Granted
- Kind: B2
- Application number: 16/135,558
- Filed: 2018-09-19
- Published: 2020-03-19
- Granted: 2020-12-22
- Earliest claimed: 2018-09-19
- Assignees: Aireon LLC
- Applicants: Aireon LLC
- Inventors: Michael A. Garcia; John Dolan
- Web page: https://patentgrep.com/patent/US10871574B2

## CPC

- G01S 19/15: Aircraft landing systems
- G01S 19/23: Testing, monitoring, correcting or calibrating of receiver elements
- G01S 5/06: Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements (G01S5/12 takes precedence)
- G01S 5/12: by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
- G01S 13/782: {using multimoding or selective addressing}
- G01S 13/91: for traffic control (G01S13/93 takes precedence)
- G01S 19/02: Details of the space or ground control segments
- 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

In one implementation, a method includes receiving a number of instances of a message that includes a self-reported position of a transmitter of the message from a corresponding number of satellite-based receivers that each received an RF transmission of an instance of the message. The method also includes determining the number of satellite-based receivers that received an instance of the message and selecting a validation technique based on the number of satellite-based receivers that received an instance of the message. If the number of satellite-based receivers that received an instance of the message is one, a propagation-based validation technique is selected. The method further includes determining a measure of the likelihood that the self-reported position of the transmitter is valid using the selected validation technique, and transmitting an indication of the measure of the likelihood that the self-reported position is valid.

## Claims

### Claim 1

A method comprising:
receiving a number of instances of a message from a corresponding number of satellite-based receivers that each received a radio frequency (“RF”) transmission of an instance of the message, the message comprising a self-reported position of a transmitter of the message;
determining the number of satellite-based receivers that received an instance of the message;
selecting a validation technique, from a plurality of validation techniques, for validating the self-reported position of the transmitter of the message based on the number of satellite-based receivers that received an instance of the message;
determining a measure of the likelihood that the self-reported position of the transmitter is valid using the selected validation technique; and
transmitting an indication of the measure of the likelihood that the self-reported position is valid.

### Claim 2 (depends on 1)

The method of claim 1, wherein selecting a validation technique for validating the self-reported position of the transmitter of the message based on the number of satellite-based receivers that received an instance of the message includes selecting, if the number of satellite-based receivers that received an instance of the message is two or more, a TDOA-based validation technique that estimates the current position of the transmitter based on times at which the satellite-based receivers that received an instance of the message received the RF transmissions of the instances of the message.

### Claim 3 (depends on 1)

The method of claim 1, wherein determining the measure of the likelihood that the self-reported position of the transmitter is valid using the selected validation technique includes determining the measure of the likelihood that the self-reported position of the transmitter is valid based on a second measure of the likelihood that a previous self-reported position of the transmitter is valid.

### Claim 4 (depends on 3)

The method of claim 3, wherein determining the measure of the likelihood that the self-reported position of the transmitter is valid using the selected validation technique includes determining the measure of the likelihood that the self-reported position of the transmitter is valid based on a length of time since the previous self-reported position of the transmitter.

### Claim 5 (depends on 1)

The method of claim 1, wherein the transmitter is hosted on an in-flight aircraft.

### Claim 6 (depends on 1)

The method of claim 1, wherein the message is an automatic dependent surveillance-broadcast (“ADS-B”) message transmitted by a transmitter on the aircraft.

### Claim 7 (depends on 1)

The method of claim 1, wherein:
determining that a total number of satellite-based receivers that received an instance of the message is one, and
the validation technique estimates the current position of the transmitter based on prior position information for the transmitter.

### Claim 8 (depends on 7)

The method of claim 7, wherein selecting a validation technique for validating the self-reported position of the transmitter of the message based on the number of satellite-based receivers that received an instance of the message includes:
determining that the number of satellite-based receivers that received an instance of the message is one, and
selecting the validation technique as a consequence of having determined that the number of satellite-based receivers that received an instance of the message is one; and
determining a measure of the likelihood that the self-reported position of the transmitter is valid using the selected validation technique includes determining a measure of the likelihood that the self-reported position of the transmitter is valid using the validation technique based on a previous position of the transmitter at a previous time, a previous speed of the transmitter at the previous time, a previous bearing of the transmitter at the previous time, and a time at which the transmitter transmitted the RF transmission of the message.

### Claim 9

A method comprising:
receiving an instance of a current message from a satellite-based receiver that received a radio frequency (“RF”) transmission of the current message, the current message comprising a self-reported position of a transmitter of the message;
estimating, based on a previous message transmitted by the transmitter at a previous time, a current position of the transmitter based on a previous position of the transmitter at the previous time, a previous speed of the transmitter at the previous time, a previous bearing of the transmitter at the previous time, and a current time at which the transmitter transmitted the RF transmission of the current message;
determining a measure of the likelihood that the self-reported position of the transmitter is valid based on a distance between the estimated current position of the transmitter and the self-reported position of the transmitter; and
transmitting an indication of the measure of the likelihood that the self-reported position is valid.

### Claim 10 (depends on 9)

The method of claim 9, wherein estimating the current position of the transmitter includes estimating a distance travelled by the transmitter between the current time and the previous time based on the previous speed of the transmitter at the previous time and the time between the current time and the previous time.

### Claim 11 (depends on 10)

The method of claim 10, wherein estimating the current position of the transmitter based on the previous position of the transmitter at the previous time, the previous speed of the transmitter at the previous time, the previous bearing of the transmitter at the previous time, and the current time at which the transmitter transmitted the RF transmission of the current message includes estimating the current position of the transmitter based on the estimated distance travelled by the transmitter between the current time and the previous time.

### Claim 12 (depends on 11)

The method of claim 11, wherein estimating the current position of the transmitter includes using Vincenty's formula to estimate the current position of the transmitter based on the previous position of the transmitter at the previous time, the previous bearing of the transmitter at the previous time, and the estimated distance travelled by the transmitter between the current time and the previous time.

### Claim 13 (depends on 9)

The method of claim 9, wherein the transmitter is hosted on an in-flight aircraft.

### Claim 14 (depends on 9)

The method of claim 9, wherein the message is an automatic dependent surveillance-broadcast (“ADS-B”) message transmitted by the transmitter on the aircraft.

### Claim 15

A system comprising:
one or more processors; and
a memory coupled to the processors comprising instructions executable by the processors, the processors being operable when executing the instructions to:
receive a number of instances of a message from a corresponding number of satellite-based receivers that each received a radio frequency (“RF”) transmission of an instance of the message, the message comprising a self-reported position of a transmitter of the message;
determine the number of satellite-based receivers that received an instance of the message;
select a validation technique, from a plurality of validation techniques, for validating the self-reported position of the transmitter of the message based on the number of satellite-based receivers that received an instance of the message;
determine a measure of the likelihood that the self-reported position of the transmitter is valid using the selected validation technique; and
transmit an indication of the measure of the likelihood that the self-reported position is valid.

### Claim 16 (depends on 15)

The system of claim 15, wherein the processors are further operable when executing the instructions to:
update a validation state for the transmitter based on the determined measure of the likelihood that the self-reported position of the transmitter is valid; and
transmit an indication of the measure of the likelihood that the self-reported position is valid based on the updated validation state for the transmitter.

### Claim 17 (depends on 15)

The system of claim 15, wherein the processors are further operable when executing the instructions to select a TDOA-based validation technique that estimates the current position of the transmitter based on times at which the satellite-based receivers that received an instance of the message received the RF transmissions of the instances of the message if the number of satellite-based receivers that received an instance of the message is two or more.

### Claim 18 (depends on 15)

The system of claim 15, wherein the processors are further operable when executing the instructions to determine the measure of the likelihood that the self-reported position of the transmitter is valid based on a second measure of the likelihood that a previous self-reported position of the transmitter is valid.

### Claim 19 (depends on 18)

The system of claim 18, wherein the processors are further operable when executing the instructions to determine the measure of the likelihood that the self-reported position of the transmitter is valid based on a length of time since the previous self-reported position of the transmitter.

### Claim 20 (depends on 15)

The system of claim 15, wherein the processors are further operable when executing the instructions to:
select the validation technique as a consequence of having determined that the number of satellite-based receivers that received an instance of the message is one;
determine a measure of the likelihood that the self-reported position of the transmitter is valid using the validation technique based on a previous position of the transmitter at a previous time, a previous speed of the transmitter at the previous time, a previous bearing of the transmitter at the previous time, and a time at which the transmitter transmitted the RF transmission of the message.

### Claim 21 (depends on 15)

The system of claim 15, wherein the message is an automatic dependent surveillance-broadcast (“ADS-B”) message transmitted by a transmitter on the aircraft.