US3801979A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integrated collision avoidance, dme, telemetry, and synchronization system
Assignee: Individual
•
Filing: 1972-04-26
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Granted: 1974-04-02
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Expires: 1992-04-26
Abstract
Abstract A time-sharing cyclic time slot system in which DME range measuring functions, collision avoidance functions, clock synchronization functions and/or data telemetry functions are all combined into an integrated repeating time sharing cycle in a non-interfering manner to achieve either general navigation and traffic control, or else stationkeeping, by the orderly exchange of pulse signals between participating ground stations and/or aircraft, and in which the cost of the system is minimized by using already existing ground and/or airborne VORTAC/TACAN/VOR/DME equipment and tuning the airborne transmitters and receivers in an agile manner to the various frequencies assigned for the performance of the above functions.
Inventors
- 👤 J Chisholm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:58
CPC Classifications
G; G01; G01S; G01S11/00; G01S11/02; G01S11/08; G01S13/00; G01S13/86
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
262 words
An aircraft navigation and collision avoidance system (CAS) of the time-sharing type in which participating aircraft occupy separate time slots in a repeating time-slot cycle and have their own airborne time clocks synchronized to a system-wide master time, and the system including common distance measuring DME transponder means interrogatable by the aircraft of an exclusively assigned transmit and receive frequency channel for determining range thereto, comprising the combination of: a. airborne distance measuring equipment (DME) in the aircraft and each including agile electronically-tuned transmitter and receiver transponder means, the airborne DME being operative when actuated to function to determine range to the common DME means whose channel is selected; b. CAS function means in each aircraft and operative when actuated to encode a position marking pulse group for transmission on a designated CAS frequency, and operative to function to determine range to other aircraft based upon the times of reception of position marking pulse groups received therefrom during monitoring of that frequency; c. occupancy-distinguishing means in each aircraft for distinguishing between portions of the time slot cycle which must be monitored and used for the CAS function and other portions of the cycle which are available for use in performing the DME function; and d. function-controlling means responsive to said occupancydistinguishing means and operative during monitored portions of the cycle to tune said transmitter and receiver means to said designated frequency and actuate said CAS means, and operative during said available portions of the cycle to tune said transmitter and receiver means to the selected DME transponder channel and actuate said DME.
Claim 2
Dependent Claim
262 words
An aircraft navigation and collision avoidance system (CAS) of the time-sharing type in which participating aircraft occupy separate time slots in a repeating time-slot cycle and have their own airborne time clocks synchronized to a system-wide master time, and the system including common distance measuring DME transponder means interrogatable by the aircraft of an exclusively assigned transmit and receive frequency channel for determining range thereto, comprising the combination of: a. airborne distance measuring equipment (DME) in the aircraft and each including agile electronically-tuned transmitter and receiver transponder means, the airborne DME being operative when actuated to function to determine range to the common DME means whose channel is selected; b. CAS function means in each aircraft and operative when actuated to encode a position marking pulse group for transmission on a designated CAS frequency, and operative to function to determine range to other aircraft based upon the times of reception of position marking pulse groups received therefrom during monitoring of that frequency; c. occupancy-distinguishing means in each aircraft for distinguishing between portions of the time slot cycle which must be monitored and used for the CAS function and other portions of the cycle which are available for use in performing the DME function; and d. function-controlling means responsive to said occupancydistinguishing means and operative during monitored portions of the cycle to tune said transmitter and receiver means to said designated frequency and actuate said CAS means, and operative during said available portions of the cycle to tune said transmitter and receiver means to the selected DME transponder channel and actuate said DME.
Claim 3
Dependent Claim
122 words
The system as set forth in claim 1, wherein the number of aircraft participating at any particular moment as well as the designation of which portions of the cycle must be used for the CAS function comprise unknown changing variables, said airborne clocks including means for counting time slots as they occur in each repeating cycle, said occupancy-distinguishing means including means for monitoring position-marking pulse groups received from other aircraft and for storing identities of the particular time slots in which they were received, and including means for comparing the stored occupied-slot identities with presently occurring slot identities; and said function-controlling means responding to coincidence in said comparing means as indicating occupied slots and to failure of coincidence as indicating unoccupied slots.
Claim 4
Dependent Claim
65 words
The system as set forth in claim 2, wherein said CAS means also includes means for evaluating the degree of threat posed by each aircraft whose position marking pulse group is received; and means based on the evaluated degree of threat for making available for the DME function those time slots which are occupied by aircraft posing a low degree of threat at the moment.
Claim 5
Dependent Claim
78 words
The system as set forth in claim 2, wherein said function-controlling means comprises means responsive to the progression from one complete time-slot cycle to another for alternating between one type of operation in which the function-controlling means actuates the DME function during unoccupied time slots and another type of operation in which the controlling means actuates the ranging-pulse group monitoring means for a complete cycle and the receiver means remains tuned continuously to monitor the designated CAS frequency.
Claim 6
Dependent Claim
111 words
The system as set forth in claim 2, wherein each common DME comprises a fixed VORTAC/TACAN type of station operating on separate and unique transmit and receive frequencies by which it is selected, each such station including means operAtive during at least one predetermined time slot for transmitting a clock synchronizing pulse group to participating aircraft selecting its channel, these pulse groups transmitted by the stations being all synchronized to said master time; and said aircraft including means responsive to the measured range of the selected DME station and to the time of reception of a transmitted synchronizing pulse group therefrom for synchronizing its own airborne clock to said master time.
Claim 7
Dependent Claim
65 words
The system as set forth in claim 5, wherein the various DME stations use the same predetermined time slots in which to transmit their synchonizing pulse groups, and wherein each participating aircraft has means for entering into said means for storing identities of occupied time slots the identities of said predetermined time slots and the identity of the time slot occupied by the aircraft itself.
Claim 8
Dependent Claim
74 words
The system as set forth in claim 5, including data link means operative between the selected DME station and the participating aircraft and including means in the aircraft for encoding CAS data and transmitting it via said transmitter means during the aircraft''s own time slot, and including means at said DME station for transmitting encoded navigation instructions to the aircraft during a time slot in which the station transmits said clock synchronizing pulse group.
Claim 9
Dependent Claim
96 words
The system as set forth in claim 2, wherein the agility of the tuning of the transmitter and receiver means is such as to require an interval for retuning which interval approaches the duration of a time slot, said occupancy-distinguishing means and said function-controlling means including means responsive to each occupied slot and operative for at least said interval before each such occupied slot to tune said transmitter and receiver means to said designated frequency, and operative for said interval of time both before and after each such occupied slot to block actuating of said DME.
Claim 10
Dependent Claim
65 words
The system as set forth in claim 1, comprising a stationkeeping system for a known number of participating aircraft respectively occupying predetermined ones of said time slots, each airborne clock including means for counting time slots as they occur in the cycle, and said occupancy-distinguishing means to which said function controlling means is responsive comprising presettable means for indicating which of said slots are occupied.
Claim 11
Dependent Claim
51 words
The system as set forth in claim 9, wherein the DME transponder means is contained within an aircraft flying as the leader of the stationkeeping system and originating the master time to which the stationkeeping system is synchronized, and the leader aircraft being assigned to occupy one of the time slots.
Claim 12
Dependent Claim
70 words
The system as set forth in claim 10, wherein the leader aircraft includes means operative during said one of said time slots for transmitting a clock synchronizing pulse group to the participating aircraft, and the latter aircraft including means responsive to the measured range to the DME transponder means and to the time of reception of each transmitted synchronizing pulse group for resynchronizing the airborne clock to said master time.
Claim 13
Dependent Claim
105 words
The system as set forth in claim 1, wherein the said CAS designated frequency is also the DME transponder interrogation frequency in the selected DME channel, and the position marking pulse group transmitted by each aircraft is encoded differently from the pulse group by which the aircraft interrogates said DME transponder means; and said function-controlling means is operative during unoccupied time slots to tune the receiver means in that aircraft to the DME transponder response frequency, and is operative during slots occupied by the aircraft to tune the same receiver means to the DME transponder interrogation frequency to receive the other aircraft ranging pulse groups.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-01 | 1977-10-01 | 1978-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-01 | 1981-10-01 | 1982-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-01 | 1985-10-01 | 1986-04-02 | $7700.00 | Window Closed / Lapsed |