US3821523A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aircraft locating system using agile tacan vortac dme
Assignee: Sierra Research Corp
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Filing: 1973-05-07
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Granted: 1974-06-28
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Expires: 1993-05-07
Abstract
Abstract A system for using ranges measured from aircraft to multiple ground stations of the TACAN, VORTAC, VOR/DME, or DME type wherein only the distance measuring features of the ground and airborne units are used to determine location of the aircraft to a high degree of accuracy far exceeding the normal capability of this type of equipment, the present system using an agile airborne DME unit which is switched in a rapid manner to interrogate said multiple ground stations successively and measure ranges thereto, the number of ground stations interrogated exceeding the minimum number required to provide a location, and a computer then processing this redundancy of range measurements by employing error factors for the measured ranges, which error factors are used in iterative computations to converge the apparent locations of the aircraft upon the actual locations.
Inventors
- 👤 J Doane
- 👤 F Maslow
- 👤 J Chisholm
- 👤 W Lennon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:09
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/87; G01S13/876
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
171 words
An improved system for the precision locating of aircraft with respect to multiple fixed ground stations each of which includes transponder distance measuring equipment (fixed DME) wherein each ground station is uniquely identifiable and selectible for interrogation to determine range thereto by cooperating distance measuring equipment (airborne DME) in participating aircraft, comprising in combination: a. in a participating aircraft an airborne DME of the agile type having means which is rapidly adjustable to select any one of said uniquely identifiable ground stations; b. presettable sequence control means coupled with said rapidly adjustable means in the airborne DME and operative to successively adjust said means to select the next station in a preset repeating sequence of fixed DME stations while the airborne DME determines range thereto and then to readjust the airborne DME to select the next fixed DME in the sequence; and c. computer means cooperative with the aircraft and operative to accept the ranges to the fixed DME stations selected in said sequence and compute the location of the aircraft.
Claim 2
Dependent Claim
171 words
An improved system for the precision locating of aircraft with respect to multiple fixed ground stations each of which includes transponder distance measuring equipment (fixed DME) wherein each ground station is uniquely identifiable and selectible for interrogation to determine range thereto by cooperating distance measuring equipment (airborne DME) in participating aircraft, comprising in combination: a. in a participating aircraft an airborne DME of the agile type having means which is rapidly adjustable to select any one of said uniquely identifiable ground stations; b. presettable sequence control means coupled with said rapidly adjustable means in the airborne DME and operative to successively adjust said means to select the next station in a preset repeating sequence of fixed DME stations while the airborne DME determines range thereto and then to readjust the airborne DME to select the next fixed DME in the sequence; and c. computer means cooperative with the aircraft and operative to accept the ranges to the fixed DME stations selected in said sequence and compute the location of the aircraft.
Claim 3
Dependent Claim
93 words
The system as set forth in claim 1, wherein separate computer means is carried by each participating aircraft and each computer means has a memory, means for entering the sequence of ground stations to be interrogated into said memory, and means connecting the computer means to actuate said sequence control means to adjust the airborne DME to select the next ground station in the sequence to be interrogated in response to the airborne DME delivering to the computer means for storage a range measurement representing the range to the last selected ground station.
Claim 4
Dependent Claim
27 words
The system as set forth in claim 2, wherein said means for entering comprises a manual entry keyboard for entering said selected ground stations into said memory.
Claim 5
Dependent Claim
73 words
The system as set forth in claim 2, wherein the system includes display means, and includes keyboard means for entering the coordinates of a course to be flown including terminal point coordinates, and the computer means includes arithmetic means operative in response to the computing of an aircraft location to determine the direction necessary to be flown to arrive at said terminal point, and means to display said direction on said display means.
Claim 6
Dependent Claim
40 words
The system as set forth in claim 4, wherein the computer arithmetic means is operative in response to the computing of an aircraft location to determine distance-to-go to said terminal point and to deliver said distance to said display means.
Claim 7
Dependent Claim
51 words
The system as set forth in claim 4, wherein said keyboard means includes means for entering multiple courses to be flown includIng start points and terminal points, and further includes means for activating one of said entered courses at a time for comparison in the computer means with computed aircraft locations.
Claim 8
Dependent Claim
108 words
The system as set forth in claim 1, wherein said computer means accepts said measured ranges comprising successive sets of ranges each set relating to one of said repeating sequences and stores them with indications of the times when they are respectively received from the airborne DME, and said computer means selecting during reception of sets of ranges arbitrary instants of time with respect to which to compute the aircraft locations, said computer means including means for interpolating between successive range measurements to the same stations to obtain ranges corrected to said arbitrarily selected instants of time, and the computer means computing locations based on these corrected ranges.
Claim 9
Dependent Claim
58 words
The system as set forth in claim 1, wherein each ground station is uniquely identifiable and selectible by selecting its frequency channel, and each airborne DME includes agile tuning transmitter and receiver means adjustable under the control of said sequence control means to tune to a selected channel for interrogating and receiving replies from the corresponding ground station.
Claim 10
Dependent Claim
74 words
The system as set forth in claim 1, wherein a common computer means serves multiple participating aircraft, data link means for transmitting the airborne DME measured ranges from the participating aircraft to the common computer means, the computer means having memory means for storing the ranges from the participating aircraft incident to computing the aircraft locations and air traffic control display means coupled to the common computer means and operative to display said locations.
Claim 11
Dependent Claim
83 words
The system as set forth in claim 9, wherein an individual sequence control means is located in each participating aircraft, each sequence control means including timed-interval stepping means for advancing the selection of the ground stations to which the airborne DME measures range, and the timed interval of each step being long enough to permit the airborne DME to be adjusted to a ground station, interrogate it, lock onto the ground station replies, and send a measured range to the common computer means.
Claim 12
Dependent Claim
65 words
The system as set forth in claim 1, wherein said presettable sequence control means selects in its sequence more fixed DME stations than the minimum number required to locate the aircraft whereby a redundancy of ranges is determined during each of said repeating sequences, and said computer means iteratively computing each aircraft location to determine the location which will best fit said redundancy of ranges.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |