How to Calculate SAR Tasking Priority Score
Synthetic aperture radar constellations juggle hundreds of daily collection requests spanning defence, insurance, infrastructure monitoring, and disaster response. Assigning satellite resources requires an auditable priority model that considers contractual urgency, time since last collect, target footprint, and pointing feasibility. This walkthrough delivers a transparent scoring methodology that operations teams can embed in their tasking software, complementing link budget calculations from the downlink margin guide and manoeuvre planning covered in the space debris conjunction delta-v article.
The scoring approach is intentionally simple: weight each task by strategic priority, urgency relative to contractual revisit intervals, footprint size, and a geometry factor that captures sensor constraints. You can adjust constants for your fleet while preserving a single deterministic output. Integrating the workflow with optical or communications analytics—such as the laser interlink margin walkthrough—creates a consistent operations stack that balances sensing, downlink, and manoeuvre budgets.
Why a transparent priority score matters
Radar operators often rely on bespoke heuristics coded into scheduling tools. Without a documented formula, it is hard to explain to regulators or customers why certain tasks were skipped. A transparent score that decomposes into measurable inputs aligns scheduling with service-level agreements (SLAs) and allows rapid auditing. It also ensures that ad-hoc overrides are tracked and justified rather than applied arbitrarily.
By using the same score in planning and post-mission review, organisations can compare expected versus actual execution, measure backlog growth, and calibrate staffing for manual interventions. The embedded calculator in this article produces the exact numbers you can feed into mission control dashboards or share with partners.
Input variables and units
Collect the following inputs for each task:
- w – Strategic priority weight (dimensionless, typically 1–5) derived from customer tiering or mission type.
- t – Hours since the last successful collect of the target footprint.
- r – Required revisit interval in hours as defined in the SLA.
- A – Task area in square kilometres. Larger footprints reduce the score because they consume more satellite time.
- g – Geometry feasibility factor (optional, dimensionless) capturing look angle, power, or duty-cycle constraints.
Keep units consistent: hours for time, square kilometres for area. Normalise priority weights across business units so a defence task scored 4 means the same thing as a commercial task scored 4. Geometry factors usually range from 0.5 to 1.2; clamp values outside that window to prevent outliers from dominating.
Score formulation
The priority score S is calculated as
S = w × min(t ÷ r, 2) × [1 ÷ (1 + A ÷ 50)] × g
The time ratio t ÷ r is capped at 2 to prevent stale tasks from indefinitely crowding the queue. The area penalty uses 50 sq km as a reference swath; adjust this constant to reflect your instrument mode. Geometry defaults to 1 when not provided. The output is dimensionless and can be compared directly between tasks. Scores near zero indicate low priority while values above three merit immediate scheduling.
Step-by-step implementation
Step 1: Catalogue mission priorities
Align business, defence, and humanitarian teams on a common weighting scheme. Document the criteria—contractual penalties, national security status, or emergency response triggers—that justify each weight. Store the mapping in your mission planning system so analysts cannot assign ad-hoc values.
Step 2: Maintain revisit telemetry
Ensure your ground segment records timestamps for each successful collect. Build data pipelines that compute t, the hours since last collect, in near real time. Flag targets with missing or failed data so analysts can adjust geometry factors or escalate to anomaly response.
Step 3: Calculate task area accurately
Use geospatial tools to measure the footprint requested by the customer. For strip-mode tasks, area equals length times swath width. Spotlight tasks may be circular or polygonal; convert them into equivalent square kilometres. Consistent area measurements prevent large maritime corridors from unfairly crowding smaller urgent tasks.
Step 4: Apply the scoring equation
Run the formula for each task and sort descending to create the execution queue. The embedded calculator below can be used for ad-hoc validation or to brief partners. Embed the calculation in your scheduling software for automation.
Step 5: Track overrides and feedback
Sometimes manual overrides are necessary—emergency response, weather anomalies, or national security directives. Log the reason for each override alongside the computed score. Review overrides monthly to adjust weights or geometry rules if a pattern emerges.
Validation and continuous improvement
Validate the scoring system by comparing scheduled versus completed tasks. If high-score tasks regularly miss execution, investigate bottlenecks such as downlink bandwidth or pointing conflicts. Use historical data to test alternative constants—for example, adjusting the area reference from 50 to 40 sq km—and measure how the queue composition changes.
Share score distributions with customers and regulators to build trust. Provide evidence that high-priority requests are consistently completed within SLA windows. Integrate the scoring output with anomaly response analytics to see whether low scores correlate with higher revisit gaps and to refine alerting thresholds.
Limitations and extensions
The simplified score does not include orbital mechanics—slew times, reaction wheel momentum, or fuel constraints. For large constellations, integrate the score with optimisation solvers that honour visibility windows and attitude limits. Likewise, if you operate multiple sensor modes, consider separate area penalties for strip versus spotlight tasks.
Future enhancements may incorporate economic value, weather forecasts for optical sensors, or cross-constellation sharing agreements. Keep the core formula lightweight so analysts can reason about it; use secondary modules for more complex optimisation.
Embed: SAR tasking priority score calculator
Supply the priority weight, hours since last collect, required revisit interval, task area, and optional geometry factor. The calculator returns the dimensionless score used to order the task queue.