US6366240B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Location of aircraft with time difference of arrival
Assignee: L3 Technologies Inc
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Filing: 2000-06-14
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Granted: 2002-04-02
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Expires: 2020-06-14
Abstract
Abstract A system and method for determining the position of an aircraft. An aircraft signal is received by a first antenna and a second antenna, the first antenna being at a known baseline distance from the second antenna. A processor is used to calculate the time difference of arrival range between the second antenna and the aircraft using a common time reference signal. The position of the aircraft is determined by a position determinator based upon the baseline distance between the first and second antennas, the range between the first antenna and the aircraft, and the time difference of arrival range between the second antenna and the aircraft.
Inventors
- 👤 LaMar K. Timothy
- 👤 Keith R. Branning
- 👤 Michael L. Ownby
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:04
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/003; G01S5/00; G01S5/02; G01S5/12; G01S13/66; G01S13/68; G01S5/06
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
128 words
A system for determining a position of an aircraft comprising: a first antenna at a first position adapted to receive an aircraft signal; a second antenna at a second position adapted to receive the aircraft signal, the second antenna being positioned at a known baseline distance from the first antenna; a processor coupled to the first and second antennas, the processor adapted to calculate a time difference of arrival range between the second antenna and the aircraft using a common time reference signal; and a position determinator adapted to determine the position of the aircraft based upon the distance between the first and second antenna, a range between the first antenna and the aircraft, and the time difference of arrival range between the second antenna and the aircraft.
Claim 2
Independent Claim
128 words
A system for determining a position of an aircraft comprising: a first antenna at a first position adapted to receive an aircraft signal; a second antenna at a second position adapted to receive the aircraft signal, the second antenna being positioned at a known baseline distance from the first antenna; a processor coupled to the first and second antennas, the processor adapted to calculate a time difference of arrival range between the second antenna and the aircraft using a common time reference signal; and a position determinator adapted to determine the position of the aircraft based upon the distance between the first and second antenna, a range between the first antenna and the aircraft, and the time difference of arrival range between the second antenna and the aircraft.
Claim 3
Dependent Claim
15 words
The system of claim 1 wherein the first antenna is a high gain directional antenna.
Claim 4
Dependent Claim
15 words
The system of claim 1 wherein the first antenna is adapted to provide range measurement.
Claim 5
Dependent Claim
14 words
The system of claim 1 wherein the first antenna is without angle tracking capability.
Claim 6
Dependent Claim
14 words
The system of claim 1 wherein the second antenna is a low gain antenna.
Claim 7
Dependent Claim
13 words
The system of claim 1 wherein the second antenna is an omni-directional antenna.
Claim 8
Dependent Claim
35 words
The system of claim 1 wherein the common time reference signal is adapted to provide a time stamp reference for a first signal from the first antenna and a second signal from the second antenna.
Claim 9
Dependent Claim
25 words
The system of claim 1 wherein the position determinator is adapted to receive a second aircraft signal to determine the three-dimensional position of the aircraft.
Claim 10
Dependent Claim
33 words
The system of claim 1 wherein the second antenna is coupled to the processor by a cable adapted to propagate the signal from the second antenna to the processor over a long distance.
Claim 11
Dependent Claim
27 words
The system of claim 1 wherein at least one fiber optic RF link is used to couple the first antenna and the second antenna to the processor.
Claim 12
Dependent Claim
22 words
The system of claim 1 wherein a receiver coupled to the second antenna includes a low noise amplifier without a down converter.
Claim 13
Independent Claim
154 words
A method for determining a position of an aircraft comprising the steps of: positioning a first antenna at a spaced baseline distance from a second antenna; receiving an aircraft signal at each of the first and second antennas; sending a first signal from the first antenna and a second signal from the second antenna to a processor, the first and second signals corresponding to the aircraft signal; determining a time difference of arrival range between the second antenna and the aircraft using a sampled data set produced by time sampling the first signal from the first antenna and the second signal from the second antenna with a common time reference signal; and determining the position of the aircraft based upon the baseline distance between the second antenna and the first antenna, a range between the first antenna and the aircraft, and the time difference of arrival range between the second antenna and the aircraft.
Claim 14
Independent Claim
154 words
A method for determining a position of an aircraft comprising the steps of: positioning a first antenna at a spaced baseline distance from a second antenna; receiving an aircraft signal at each of the first and second antennas; sending a first signal from the first antenna and a second signal from the second antenna to a processor, the first and second signals corresponding to the aircraft signal; determining a time difference of arrival range between the second antenna and the aircraft using a sampled data set produced by time sampling the first signal from the first antenna and the second signal from the second antenna with a common time reference signal; and determining the position of the aircraft based upon the baseline distance between the second antenna and the first antenna, a range between the first antenna and the aircraft, and the time difference of arrival range between the second antenna and the aircraft.
Claim 15
Dependent Claim
25 words
The method of claim 12 wherein the range between the first antenna and the aircraft is determined by a ranging calculation of the first antenna.
Claim 16
Dependent Claim
88 words
The method of claim 12 wherein the step of determining a time difference of arrival range between the second antenna and the aircraft comprises the steps of: determining a time difference of arrival range between the first signal and the second signal using the sampled data set; and calculating the time difference of arrival between the second antenna and the aircraft based upon the time difference of arrival between the first and the second signals, the range between the first antenna and the aircraft, and the-speed of light.
Claim 17
Dependent Claim
43 words
The method of claim 14 wherein the step of calculating a time difference of arrival between the first signal and the second signal comprises the step of performing a cross correlation on the sampled data set to determine the time difference of arrival.
Claim 18
Dependent Claim
23 words
The method of claim 12 further comprising the steps of: receiving a second aircraft signal; and determining a three-dimensional position of the aircraft.
Claim 19
Dependent Claim
24 words
The method of claim 12 wherein the spaced baseline distance between the first antenna and the second antenna is approximately 1000 feet (304.80 meters).
Claim 20
Dependent Claim
34 words
The method of claim 12 wherein a sampling rate for time sampling the first signal and the second signal is at least two times a bandwidth of the first signal and the second signal.
Claim 21
Independent Claim
151 words
A method of using a time difference of arrival processor to determine a position of an aircraft transmitting a signal comprising the steps of: determining a range (R 1 ) between a second antenna and the aircraft by measuring a range (R 2 ) between a first antenna and the aircraft and calculating a time difference of arrival between the signal from the aircraft received by the second antenna and the signal from the aircraft received by the first antenna using a common time reference signal, the time difference of arrival being adjusted for a time slippage correlation delay and speed of light; and determining the position of the aircraft based on a baseline distance (R 3 ) between the first antenna and the second antenna, the range (R 2 ) between the first antenna and the aircraft and the range (R 1 ) between the second antenna and the aircraft.
Claim 22
Independent Claim
151 words
A method of using a time difference of arrival processor to determine a position of an aircraft transmitting a signal comprising the steps of: determining a range (R 1 ) between a second antenna and the aircraft by measuring a range (R 2 ) between a first antenna and the aircraft and calculating a time difference of arrival between the signal from the aircraft received by the second antenna and the signal from the aircraft received by the first antenna using a common time reference signal, the time difference of arrival being adjusted for a time slippage correlation delay and speed of light; and determining the position of the aircraft based on a baseline distance (R 3 ) between the first antenna and the second antenna, the range (R 2 ) between the first antenna and the aircraft and the range (R 1 ) between the second antenna and the aircraft.
Claim 23
Dependent Claim
65 words
The method of claim 19 wherein the range (R 1 ) between the second antenna and the aircraft is determined by the formula: R 1 =R 2 +TDOA×c where TDOA equal the time difference of arrival between the signal from the aircraft received by the second antenna and the signal from the aircraft received by the first antenna, and c equals the speed of light.
References Cited (Backward Citations)
US5285209A
Cited
US5724047A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2005-04-01 | 2005-10-01 | 2006-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-04-01 | 2009-10-01 | 2010-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-04-01 | 2013-10-01 | 2014-04-02 | $7700.00 | Window Closed / Lapsed |