US3594799A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vor/dme, tacan and vortac having increased capability
Assignee: Sierra Research Corp
•
Filing: 1969-09-10
•
Granted: 1971-07-20
•
Expires: 1989-09-10
Abstract
Abstract A modified VOR/DME, TACAN or VORTAC system having ground stations synchronized to a master time and transmitting marker signals timed to a precise rate by the clock, and having a DME transponder; in combination with aircraft having standard DME cooperating with the ground DME to measure range by the round trip pulse technique, and the aircraft each having a local time clock and means to synchronize the time clock to the ground station clocks upon receipt of a marker signal by using the twoway DME measured range to compensate for marker signal transit time to the aircraft, and the aircraft including one-way range measuring and indicating means based on local synchronized clock time, and the aircraft further including means to render the clock synchronizing means and the two-way DME range measuring means operative only during brief intervals interspersed with much longer inoperative intervals, thereby to reduce the frequency of ground station DME interrogations by each aircraft without reducing the rate of range data acquisition thereby.
Inventors
- 👤 Lewis Michnik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:58
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/74; G01S13/76; G01S13/78; G01S13/785; G01S13/787
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
192 words
A system for increasing the capability of a VOR/DME, VORTAC or TACAN type fixed-position station with regard tO the number of aircraft that it can serve at a given time, comprising in combination: a. transponder means at each ground station responsive to interrogation by said aircraft to transmit a reply signal to the aircraft; b. DME means in each aircraft for interrogating the transponder means and computing range to the station based upon the elapsed time between its interrogation and the reception of said reply signal; c. cyclic time clock means at each ground station for initiating at accurately predetermined instants transmissions from the station of marker pulse groups; d. clock means in each aircraft for counting out a similar time cycle; e. means at the aircraft for synchronizing the aircraft clock means with the ground station clock means based upon said DME computed range and upon the moment of reception of the ground station marker pulse group; and f. repeating switch means operative to enable said aircraft DME and said synchronizing means for relatively short intervals of time as compared with longer intervening intervals of time during which they are disabled.
Claim 2
Independent Claim
192 words
A system for increasing the capability of a VOR/DME, VORTAC or TACAN type fixed-position station with regard tO the number of aircraft that it can serve at a given time, comprising in combination: a. transponder means at each ground station responsive to interrogation by said aircraft to transmit a reply signal to the aircraft; b. DME means in each aircraft for interrogating the transponder means and computing range to the station based upon the elapsed time between its interrogation and the reception of said reply signal; c. cyclic time clock means at each ground station for initiating at accurately predetermined instants transmissions from the station of marker pulse groups; d. clock means in each aircraft for counting out a similar time cycle; e. means at the aircraft for synchronizing the aircraft clock means with the ground station clock means based upon said DME computed range and upon the moment of reception of the ground station marker pulse group; and f. repeating switch means operative to enable said aircraft DME and said synchronizing means for relatively short intervals of time as compared with longer intervening intervals of time during which they are disabled.
Claim 3
Dependent Claim
32 words
In a system as set forth in claim 1, said repeating switch means having a random component in its time interval determinations whereby the time intervals are not all of identical duration.
Claim 4
Dependent Claim
88 words
In a system as set forth in claim 1, said synchronizing means having signals for indicating when the clock means in the aircraft is and is not closely synchronized to the ground clock means; gate means responsive to not-synchronized condition for actuating the DME in the aircraft to measure range during both the short and the longer intervals, and responsive to closely synchronized condition to actuate the DME to measure range during said short intervals and to disable the DME and the synchronizing means during said longer intervals.
Claim 5
Dependent Claim
80 words
In a system as set forth in claim 1, each aircraft including means for displaying range to a ground station; means for making one-way range measurements to a ground station based upon the predetermined instants of ground station transmissions of its marker pulse groups and upon the instants of reception at the aircraft of those pulse groups, both as determined by the aircraft synchronized clock means; and means coupling the one-way range measurements to the display means in the aircraft.
Claim 6
Dependent Claim
69 words
In a system as set forth in claim 4, said aircraft DME including means to lock onto reply signals generated in response to its own interrogations of the ground station during said short intervals, and gate means operative during said longer intervals of inactivity of said DME for introducing thereinto range information from said means for making one-way range measurements to maintain alive said lock-on means of the DME.
References Cited (Backward Citations)
US3440652A
Cited
US3521278A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-07-19 | 1975-01-18 | 1975-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-19 | 1979-01-18 | 1979-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-19 | 1983-01-18 | 1983-07-20 | $7700.00 | Window Closed / Lapsed |