Patent US3821735A successfully refreshed from Google Patents.
US3821735A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital data refreshing apparatus for radar display system
Assignee: Unisys Corp
•
Filing: 1973-01-29
•
Granted: 1974-06-28
•
Expires: 1993-01-29
Abstract
Abstract In an air traffic control system, real-time digitized radar target data is stored in a virtual pushdown stack memory and is repetitively fed to a CRT display system at a rate sufficient to generate a steady flicker-free display. Identification of the data to be displayed as either that derived and stored during the radar antenna''s most recent scan or that generated by past scans provides the option of displaying a target''s current position by one indicium and its past positions by other indicia whereby a moving target may be displayed as a small symbol followed by a selectable number of trailing dots thereby allowing the observer to readily assess the target''s current position, its heading, and by noting the spacing of the dots, its speed. By allocating memory space to the most recent data and discarding the oldest data, graceful degradation occurs in target data overload situations whereby the lost data effects merely a reduction in the number of trailing dots per target.
Inventors
- 👤 M Lasoff
- 👤 R Baldwin
- 👤 H Natanblut
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:25
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/28; G01S7/2806; G01S7/04; G01S7/06; G01S7/22
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
211 words
The process of generating a flicker-free display in a radar display system for receiving and displaying each of a plurality of digitized radar target data messages for a preselectable display period, comprising the steps of: appending to each of said received digitized radar target data message a control field including a display time sub-field defining a display time; storing sequentially each of said appended received digitized radar target data message; reading non-destructively each of said stored appended received digitized radar target data message on a last in - first out basis; sending to said display system each of said read digitized radar target data message; repeating said steps of reading and sending at a rate responsive to the persistence characteristics of said display system for generating a steady flicker-free display presentation of each of said received digitized radar target data messages; modifying periodically said defined display time of said subfield of said stored appended control field of each of said digitized radar target data message sent; comparing said modified display time of said sub-field of each of said sent radar target data message with said preselectable display period for coincidence detection; and inhibiting the further sending of each of said digitized radar target data message for which said coincidence is detected.
Claim 2
Dependent Claim
211 words
The process of generating a flicker-free display in a radar display system for receiving and displaying each of a plurality of digitized radar target data messages for a preselectable display period, comprising the steps of: appending to each of said received digitized radar target data message a control field including a display time sub-field defining a display time; storing sequentially each of said appended received digitized radar target data message; reading non-destructively each of said stored appended received digitized radar target data message on a last in - first out basis; sending to said display system each of said read digitized radar target data message; repeating said steps of reading and sending at a rate responsive to the persistence characteristics of said display system for generating a steady flicker-free display presentation of each of said received digitized radar target data messages; modifying periodically said defined display time of said subfield of said stored appended control field of each of said digitized radar target data message sent; comparing said modified display time of said sub-field of each of said sent radar target data message with said preselectable display period for coincidence detection; and inhibiting the further sending of each of said digitized radar target data message for which said coincidence is detected.
Claim 3
Dependent Claim
201 words
A radar target display refreshing apparatus for receiving, storing and repeatedly sending to a display system having a known finite display persistence a plurality of digitized radar target data messages comprising: means for selectably setting a radar target data message display period including data for timing said display period; message control means for appending to each of the messages a control field including said data for timing; memory means for sequentially storing each of said received messages with its appended control field; means for non-destructively reading on a last in - first out basis each of said stored messages with its appended control field; refreshing means for repeatedly activating said reading means and for sending to the display system said messages at a rate determined by the persistence characteristics of said display system for generating a flicker-free display presentation of each of said radar target data messages; means responsive to said timing data for clocking said display; and display control means responsive to said period setting means and said clocking means for permitting the repeated sending of each of said messages by said refreshing means for a time equal to said selectably set display period and for inhibiting said sending thereafter.
Claim 4
Dependent Claim
201 words
A radar target display refreshing apparatus for receiving, storing and repeatedly sending to a display system having a known finite display persistence a plurality of digitized radar target data messages comprising: means for selectably setting a radar target data message display period including data for timing said display period; message control means for appending to each of the messages a control field including said data for timing; memory means for sequentially storing each of said received messages with its appended control field; means for non-destructively reading on a last in - first out basis each of said stored messages with its appended control field; refreshing means for repeatedly activating said reading means and for sending to the display system said messages at a rate determined by the persistence characteristics of said display system for generating a flicker-free display presentation of each of said radar target data messages; means responsive to said timing data for clocking said display; and display control means responsive to said period setting means and said clocking means for permitting the repeated sending of each of said messages by said refreshing means for a time equal to said selectably set display period and for inhibiting said sending thereafter.
Claim 5
Dependent Claim
159 words
The radar target display refreshing apparatus according to claim 2 wherein said display system includes the capability of displaying data through a plurality of indicia and wherein said display period setting means includes: means for selectively setting a first portion of said radar target data message display period including said timing data; and means for selectably setting the remaining portion of said radar target data message display period; and wherein said refreshing means includes: detection means responsive to said period selecting means and to said clocking means for generating a signal indicative of whether the elapsed time of display of each of said messages is in said first portion or said remaining portion of said display period; and means for appending said generated signal to each of said radar target data messages sent to the display system to control the display thereof, thereby displaying one indicium during said first portion of said selectable display period and another indicium thereafter.
Claim 6
Dependent Claim
47 words
The radar target display refreshing apparatus according to claim 3 wherein said first portion display setting means includes: means for initially setting said timing data to the binary complement of a binary number representing said selectably set first portion of said radar target data message display period.
Claim 7
Dependent Claim
65 words
The radar target data display refreshing apparatus according to claim 4 wherein said clocking means includes: means for periodically bit-by-bit incrementing at a constant rate said binary complement representation, said rate being selected to increment said binary complement representation to the binary representation of zero in a period of time equal to said selectably set first portion of said radar target data message display period.
Claim 8
Dependent Claim
119 words
The radar target data display refreshing apparatus according to claim 5 wherein said detection means includes: logic gating means for generating a signal of one binary logic level indicating that said binary complement representation has not been incremented to the binary representation of zero and of a second binary logic level signal indicating otherwise; means for latching said generated indicating logic level signal from substantially the time of reading of said control field of one target data message out of said memory means to the time of reading of the next said control field; and wherein said generated signal appended means includes: means for prefixing said latched signal of said logic gating means to each of said sent messages.
Claim 9
Dependent Claim
104 words
The radar target display refreshing apparatus according to claim 5 wherein said message control means includes: means cooperating with said first portion display setting means for positioning the least significant digit of said binary complement representation contiguous to one end of said control field; and means for setting to a logical one level all of a plurality of bits in a part of said control field, said part being adjacent to said binary complement representation and being responsive to said bit-by-bit incrementing means whereby said plurality of bits function as digits of greater significance than the most significant digit of said binary complement representation.
Claim 10
Dependent Claim
98 words
The radar target data display refreshing apparatus according to claim 7 wherein said detection means also includes: logical AND circuit means monitoring said plurality of bits for generating a logical level signal when at least one of said plurality of bits has been incremented to a logical zero level therEby indicating that said binary representation has been incremented to logical zero; and means for latching said generated logic level signal from substantially the time of reading of said control field of one target data message out of said memory means to the reading of next said control field.
Claim 11
Dependent Claim
153 words
The radar target display refreshing apparatus according to claim 7 wherein said remaining portion display setting means includes: means for generating a binary number representing said selectably set remaining portion of said radar target data message display period; means for comparing said generated binary number representing said selectably set remaining portion of said radar target data message display period with said binary number represented by said binary complement representation and said plurality of bits, as incremented by said clocking means, of the individual message being read of said plurality of messages; means responsive to said comparing means for generating a signal indicating equality of said generated number representing said selected remaining portion of said message display period and said binary number represented by said binary complement representation and said plurality of bits, as incremented by said clocking means; and wherein said signal indicating equality defines the end of said selectably set display period.
Claim 12
Dependent Claim
192 words
The radar target display refreshing apparatus according to claim 9 wherein said message control means includes: means cooperating with said first portion display setting means for positioning the least significant digit of said binary complement representation contiguous to one end of said control field; and means for setting to a logical one level all of a plurality of bits in a part of said control field, said part being adjacent to said binary complement representation and being responsive to said bit-by-bit incrementing means whereby said plurality of bits function as digits of greater significance than the most significant digit of said binary complement representation; and wherein said detection means also includes: logical AND circuit means monitoring said plurality of bits for generating a logic level signal when at least one of said plurality of bits has been incremented to a logical zero level thereby indicating that said binary representation has been incremented to logical zero; and means for latching said generating logic level signal from substantially the time of reading of said control field of one target data message out of said memory means to the reading of next said control field.
Claim 13
Dependent Claim
152 words
The radar target display refreshing apparatus according to claim 2 wherein said plurality of digitized radar target data messages comprises messages having an identical plurality of fields including a label field as the first field in each message immediately followed by a number of subsequent fields containing relevant information, said label field including an indication of said number of subsequent fields containing relevant information, all said plurality of fields having an identical plurality of bits; and wherein said message control means includes means for prefixing to each of said received messages said control field including said data for timing, said control field containing said identical plurality of bits; and wherein said memory means includes: means for sequentially storing each of said received messages with its prefixed control field field-by-field in reverse order whereby the last field of each message is stored adjacent to said prefixed control field of the immediately preceding message.
Claim 14
Dependent Claim
88 words
The radar target display refreshing system according to claim 11 wherein said message control means further includes: means for decoding said label field with respect to said indication of said number of subsequent fields containing relevant information; and means responsive to said decoding means for including within said prefixed controL field at least one bit denoting the number of subsequent fields containing relevant information; and wherein said memory means also includes: means responsive to said included at least one bit for storing only subsequent fields containing relevant information.
Claim 15
Dependent Claim
66 words
The radar display refreshing system according to claim 12 wherein said refreshing means also includes: means responsive to said included at least one bit for suffixing to each said read radar target data message a field of said identical plurality of bits for each nonrelevant field not stored in said memory means, thereby sending to the display system only messages having said identical plurality of fields.
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 |