EP2188719A1 - Real time priority based scheduling for radar tasks - Google Patents

Real time priority based scheduling for radar tasks

Info

Publication number
EP2188719A1
EP2188719A1 EP08788723A EP08788723A EP2188719A1 EP 2188719 A1 EP2188719 A1 EP 2188719A1 EP 08788723 A EP08788723 A EP 08788723A EP 08788723 A EP08788723 A EP 08788723A EP 2188719 A1 EP2188719 A1 EP 2188719A1
Authority
EP
European Patent Office
Prior art keywords
task
radar
ready
time
tasks
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP08788723A
Other languages
German (de)
French (fr)
Inventor
Charles Christopher Ian Wigmore
William Kenneth Stafford
Paul Birch
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BAE Systems PLC
Original Assignee
BAE Systems PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB0717973A external-priority patent/GB0717973D0/en
Application filed by BAE Systems PLC filed Critical BAE Systems PLC
Priority to EP08788723A priority Critical patent/EP2188719A1/en
Publication of EP2188719A1 publication Critical patent/EP2188719A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/66—Radar-tracking systems; Analogous systems
    • G01S13/72—Radar-tracking systems; Analogous systems for two-dimensional [2D] tracking, e.g. combination of angle and range tracking, track-while-scan radar
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F9/00—Arrangements for program control, e.g. control units
    • G06F9/06—Arrangements for program control, e.g. control units using stored programs, i.e. using an internal store of processing equipment to receive or retain programs
    • G06F9/46—Multiprogramming arrangements
    • G06F9/48—Program initiating; Program switching, e.g. by interrupt
    • G06F9/4806—Task transfer initiation or dispatching
    • G06F9/4843—Task transfer initiation or dispatching by program, e.g. task dispatcher, supervisor, operating system
    • G06F9/4881—Scheduling strategies for dispatcher, e.g. round robin, multi-level priority queues
    • G06F9/4887—Scheduling strategies for dispatcher, e.g. round robin, multi-level priority queues involving deadlines, e.g. rate based, periodic
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2209/00—Indexing scheme relating to G06F9/00
    • G06F2209/50—Indexing scheme relating to G06F9/50
    • G06F2209/5021—Priority

Definitions

  • the present invention relates to a scheduling scheme for multi function radar. Specifically, the present invention relates to an urgency based time scheduler for multi function radar.
  • a known method of radar scheduling is shown in Figure 1 , and consists of scheduling tasks ad hoc for the next time slot (in the example of Figure 1 , the time slots are 10ms). This results in gaps in radar usage when there is not a sufficient number of tasks to perform, and is therefore inefficient.
  • the present invention provides a method of scheduling tasks to be performed by a radar comprising the steps of: (i) allocating a priority to each radar function to be performed; (ii) allocating a readiness level to each task within each function wherein a predetermined value of the readiness level is determined to indicate that a said task is ready; and (iii) performing the task that has the highest priority and is ready.
  • the advantage of the present invention is that the radar time is allocated to tasks deemed “ready” such that the radar time is fully utilised whilst allowing higher priority functions to be performed as a priority over lower priority functions.
  • the scheduler of the present invention should allow a radar to perform more functions is a more responsive and flexible manner and fully utilise the radar antenna.
  • FIG. 1 is a diagram illustrating the ad hoc allocation of slots in the next time slot by a known time scheduling scheme
  • Figure 2 is a diagram showing an example of a radar job table with a list of tasks to be performed by the radar and an associated priority for each task;
  • Figure 3 is a diagram showing a cross section of the volume in which the radar can operate, divided into sections;
  • Figures 4 and 5 are diagrams showing two different jobs with differing associated repetition frequencies;
  • Figures 6a, 6b, 6c, 6d and 6e are diagrams showing the progress of a job over time; and Figure 7 is a flowchart illustrating the process of performing a task and maintaining the time balance of the tasks.
  • the radar load of a task to be performed by a radar is known as the occupancy of a task, and is given (as a percentage) by the formula:
  • Occupancy Number of Beams x Dwell Time
  • the radar job table of the specific embodiment of the present invention is shown, listing exemplary functions that the radar performs.
  • the present invention allocates priorities to each function that the radar apparatus has to perform.
  • the scheduler For each task in the radar job table, the scheduler maintains a readiness level, or time balance, two examples of which are shown in Figures 4 and 5. For each task, there is a p re-determined dwell time that the radar needs to spend on the task for the respective zone. The amount of time between occurrences of that task being performed is determined by the radar occupancy of the task as follows. When any task is executed on the radar, the amount of radar time used is allocated to the time balances of the other tasks in the job table, starting with the highest priority and in proportion to their occupancies. For example, if a task has a 10% occupancy, its time balance is incremented with 10% of the radar time used after each task executes.
  • the task When the readiness level of a task reaches zero, the task is deemed to be "ready".
  • the scheduler operates by picking the highest priority task that is "ready” or, if no tasks are “ready”, then it picks the task that is closest to being “ready”. So, referring to Figure 2, the scheduler starts from the top of the radar job table and works down until it reaches a "ready” task. If none are “ready”, then it picks the most "ready” task in the lowest level of the job table, i.e. the task with the lowest priority task that has the highest readiness level. This constitutes a mechanism for controlling radar behaviour when radar is underloaded since, when total of all the task occupancies is less than 100%, the jobs in the lowest priority level are performed at an increased rate to absorb spare radar time.
  • the time balances of other tasks are then incremented as described above and the time balance of the task that has been executed is decremented by the radar dwell time that it used.
  • FIGs 6a to 6e there is shown an example of the time balance of a task over time.
  • Figure 6a shows the task on initialisation of the scheduler - the dwell time of the task is subtracted from the time balance, so the time balance starts with a value of -T dwe ⁇ -
  • Figure 6b another task is performed, so the dwell time for that task is shared amongst the other tasks as described above .
  • Figure 6c again another task is performed, so the dwell time for that task also shared amongst the other tasks as described above, bringing the example task to the "ready" value of zero.
  • Figure 6d as the task is now "ready", it is performed by the scheduler and the dwell time used is subtracted from the time balance.
  • Figure 6e as the task is no longer "ready”, another task is - A - performed, so the dwell time for that task is shared amongst the other tasks as described above. The process continues accordingly.
  • FIG 7 a flow diagram is shown outlining the process followed by the scheduler.
  • the system initialises: the priorities for all of the tasks are determined and the respective time balances are all set to equal the tasks' respective negative dwell times. Other initialisation steps will be necessary, and should be clear to the skilled person implementing this scheduling method from the description above.
  • the next step is for the process of scheduling to begin: the task with the highest priority that is "ready” is performed or, if there is not a "ready” task, the task with the highest priority that is closest to being "ready” (i.e. has the least negative time balance) in the lowest priority level is performed.

Landscapes

  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Software Systems (AREA)
  • Theoretical Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Engineering & Computer Science (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Traffic Control Systems (AREA)

Abstract

The present invention relates to a scheduling scheme for multi function (5) radar. Specifically, the present invention relates to a priority based time scheduler for multifunction radar. The present invention provides a method of scheduling tasks to be performed by a radar comprising the steps of: (i) allocating a priority to each task to be performed; (ii) allocating a readiness level to each said task wherein (10) a predetermined value of the readiness level is determined to indicate that a said task is ready; and (iii) performing the task that has the highest priority and is ready.

Description

REAL TIME PRIORITY BASED SCHEDULING FOR RADAR TASKS
The present invention relates to a scheduling scheme for multi function radar. Specifically, the present invention relates to an urgency based time scheduler for multi function radar.
A known method of radar scheduling is shown in Figure 1 , and consists of scheduling tasks ad hoc for the next time slot (in the example of Figure 1 , the time slots are 10ms). This results in gaps in radar usage when there is not a sufficient number of tasks to perform, and is therefore inefficient. The present invention provides a method of scheduling tasks to be performed by a radar comprising the steps of: (i) allocating a priority to each radar function to be performed; (ii) allocating a readiness level to each task within each function wherein a predetermined value of the readiness level is determined to indicate that a said task is ready; and (iii) performing the task that has the highest priority and is ready.
The advantage of the present invention is that the radar time is allocated to tasks deemed "ready" such that the radar time is fully utilised whilst allowing higher priority functions to be performed as a priority over lower priority functions. Thus, the scheduler of the present invention should allow a radar to perform more functions is a more responsive and flexible manner and fully utilise the radar antenna.
Specific embodiments of the invention will now be described, by way of example only and with reference to the accompanying drawings that have like reference numerals, wherein:- Figure 1 is a diagram illustrating the ad hoc allocation of slots in the next time slot by a known time scheduling scheme;
Figure 2 is a diagram showing an example of a radar job table with a list of tasks to be performed by the radar and an associated priority for each task;
Figure 3 is a diagram showing a cross section of the volume in which the radar can operate, divided into sections; Figures 4 and 5 are diagrams showing two different jobs with differing associated repetition frequencies; and
Figures 6a, 6b, 6c, 6d and 6e are diagrams showing the progress of a job over time; and Figure 7 is a flowchart illustrating the process of performing a task and maintaining the time balance of the tasks.
The specific embodiment of the present invention will now be described with reference to Figures 2, 3, 4, 5, 6a to 6e and 7:
The radar load of a task to be performed by a radar is known as the occupancy of a task, and is given (as a percentage) by the formula:
Occupancy = Number of Beams x Dwell Time
Frame Time
With reference to Figure 2, the radar job table of the specific embodiment of the present invention is shown, listing exemplary functions that the radar performs. The present invention allocates priorities to each function that the radar apparatus has to perform. In the example radar job table shown in Figure 2, there are six functions of which "NCTR" has the highest priority, represented by being associated with numeral 6 in the table, and "Surveillance" has the lowest priority, represented by being associated with numeral 1 in the table.
For each task in the radar job table, the scheduler maintains a readiness level, or time balance, two examples of which are shown in Figures 4 and 5. For each task, there is a p re-determined dwell time that the radar needs to spend on the task for the respective zone. The amount of time between occurrences of that task being performed is determined by the radar occupancy of the task as follows. When any task is executed on the radar, the amount of radar time used is allocated to the time balances of the other tasks in the job table, starting with the highest priority and in proportion to their occupancies. For example, if a task has a 10% occupancy, its time balance is incremented with 10% of the radar time used after each task executes. This constitutes a mechanism for controlling behaviour when the radar is overloaded since when the total of all the task occupancies exceeds 100% then some tasks in the lower priority levels of the radar Job table will not have their time balances incremented i.e. their time balances will not become "ready" until the overload is over. A new task starts its life with a time balance which is negative but equal in magnitude to the radar dwell time it will use.
When the readiness level of a task reaches zero, the task is deemed to be "ready". The scheduler operates by picking the highest priority task that is "ready" or, if no tasks are "ready", then it picks the task that is closest to being "ready". So, referring to Figure 2, the scheduler starts from the top of the radar job table and works down until it reaches a "ready" task. If none are "ready", then it picks the most "ready" task in the lowest level of the job table, i.e. the task with the lowest priority task that has the highest readiness level. This constitutes a mechanism for controlling radar behaviour when radar is underloaded since, when total of all the task occupancies is less than 100%, the jobs in the lowest priority level are performed at an increased rate to absorb spare radar time.
The time balances of other tasks are then incremented as described above and the time balance of the task that has been executed is decremented by the radar dwell time that it used.
In Figures 6a to 6e, there is shown an example of the time balance of a task over time. Figure 6a shows the task on initialisation of the scheduler - the dwell time of the task is subtracted from the time balance, so the time balance starts with a value of -Tdweιι- In Figure 6b, another task is performed, so the dwell time for that task is shared amongst the other tasks as described above . In Figure 6c, again another task is performed, so the dwell time for that task also shared amongst the other tasks as described above, bringing the example task to the "ready" value of zero. In Figure 6d, as the task is now "ready", it is performed by the scheduler and the dwell time used is subtracted from the time balance. In Figure 6e, as the task is no longer "ready", another task is - A - performed, so the dwell time for that task is shared amongst the other tasks as described above. The process continues accordingly.
In Figure 7, a flow diagram is shown outlining the process followed by the scheduler. First, the system initialises: the priorities for all of the tasks are determined and the respective time balances are all set to equal the tasks' respective negative dwell times. Other initialisation steps will be necessary, and should be clear to the skilled person implementing this scheduling method from the description above. The next step is for the process of scheduling to begin: the task with the highest priority that is "ready" is performed or, if there is not a "ready" task, the task with the highest priority that is closest to being "ready" (i.e. has the least negative time balance) in the lowest priority level is performed. Once this task is performed, the time balance for the performed task has the dwell time subtracted from its time balance and the unperformed tasks are incremented by the dwell time as described above. The process then repeats. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.

Claims

Claims
1 . A method of scheduling tasks to be performed by a radar comprising the steps of: (i) allocating a priority to each task to be performed;
(ii) allocating a readiness level to each said task wherein a predetermined value of the readiness level is determined to indicate that a said task is ready; and
(iii) performing the task that has the highest priority and is ready.
2. A method according to claim 1 , further comprising the step of:
(iv) performing the task with the highest readiness in the lowest priority level if no task is ready.
3. A method according to claim 1 or claim 2 wherein, when a task is performed, the step of incrementing the readiness levels of the unperformed tasks is carried out.
4. A method according to claim 3 wherein said increment for each unperformed task is given by a dwell time spent on the performed task multiplied by the occupancy of the unperformed task starting at the highest priority level 5. A method according to any preceding claim further comprising the step of:
(v) subtracting the dwell time spent on the performed task from the readiness level of the performed task.
6. A radar apparatus operable to carry out the method according to any of claims 1 to 5.
7. A method substantially as hereinbefore described with reference to Figures 2 to 4b.
8. An apparatus substantially as hereinbefore described with reference to Figures 2 to 4b.
EP08788723A 2007-09-14 2008-08-29 Real time priority based scheduling for radar tasks Withdrawn EP2188719A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP08788723A EP2188719A1 (en) 2007-09-14 2008-08-29 Real time priority based scheduling for radar tasks

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
EP07270051 2007-09-14
GB0717973A GB0717973D0 (en) 2007-09-14 2007-09-14 Real time priority based scheduling
EP08788723A EP2188719A1 (en) 2007-09-14 2008-08-29 Real time priority based scheduling for radar tasks
PCT/GB2008/050752 WO2009034368A1 (en) 2007-09-14 2008-08-29 Real time priority based scheduling for radar tasks

Publications (1)

Publication Number Publication Date
EP2188719A1 true EP2188719A1 (en) 2010-05-26

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Application Number Title Priority Date Filing Date
EP08788723A Withdrawn EP2188719A1 (en) 2007-09-14 2008-08-29 Real time priority based scheduling for radar tasks

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EP (1) EP2188719A1 (en)
AU (1) AU2008299666A1 (en)
WO (1) WO2009034368A1 (en)

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Publication number Priority date Publication date Assignee Title
CN101887381A (en) * 2010-06-22 2010-11-17 北京伟库电子商务科技有限公司 Method and device for configuring timing tasks based on Quartz frame
CN103617359B (en) * 2013-12-04 2017-06-16 中国船舶重工集团公司第七二四研究所 A kind of many front rotating phased array radar method for scheduling task
CN112346845B (en) * 2021-01-08 2021-04-16 腾讯科技（深圳）有限公司 Method, device and equipment for scheduling coding tasks and storage medium
CN116911526A (en) * 2023-06-19 2023-10-20 成都信息工程大学 Cooperative control method for weather radar networking

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Publication number Priority date Publication date Assignee Title
WO1992017796A1 (en) * 1991-03-28 1992-10-15 The Commonwealth Of Australia Radar control task scheduling
AU658412B2 (en) * 1991-05-24 1995-04-13 Commonwealth Of Australia, The Optimising radar tasking using backwards scheduling

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2009034368A1 *

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Publication number Publication date
AU2008299666A1 (en) 2009-03-19
WO2009034368A1 (en) 2009-03-19

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