Acceptance Criteria for Interoperability: How to Prove Compatibility

Interoperability is not a feeling. It is a set of measurable outcomes that prove two systems can work together under real operating conditions. In ground stations, “compatibility” can mean many things at once: RF lock, correct decoding, clean metadata, predictable scheduling behavior, secure access, and reliable delivery to downstream systems. This guide explains how to write acceptance criteria for interoperability and how to run tests that give everyone confidence before operations go live.

Table of contents

1. What Interoperability Means in Ground Station Terms
2. Why Acceptance Criteria Matter
3. Define the Scope: Interfaces, Not Just Systems
4. Acceptance Criteria Principles: Clear, Measurable, Repeatable
5. RF and Link-Layer Acceptance Criteria
6. Baseband and Protocol Acceptance Criteria
7. Operational Workflow Acceptance Criteria
8. Data Products, Metadata, and Delivery Acceptance Criteria
9. Security and Access Acceptance Criteria
10. Resilience and Failure-Mode Acceptance Criteria
11. Test Planning: How to Run a Credible Interoperability Campaign
12. Evidence Pack: What to Collect to Prove Compatibility
13. Common Mistakes and How to Avoid Them
14. Glossary: Interoperability Terms

What Interoperability Means in Ground Station Terms

In ground station operations, interoperability is the ability to connect components, teams, and services so that mission goals are met without fragile, manual workarounds. It often spans multiple layers at once:

• RF and pointing: the antenna can acquire and track with stable signal quality.
• Baseband: the receiver can demodulate, decode, and reconstruct the bitstream correctly.
• Protocol and framing: the system can interpret frames, packets, and encapsulation as expected.
• Operations: scheduling, pass execution, and reporting behave predictably.
• Data handling: products are delivered with correct naming, metadata, and integrity checks.
• Security: access control and audit logs meet required standards.

Because the scope is broad, a good acceptance plan breaks interoperability into testable interfaces, then defines what “pass” looks like for each interface.

Why Acceptance Criteria Matter

Teams often discover late that they have different definitions of “working.” One team means “we can see a carrier.” Another means “we can deliver usable data to end users within a time limit.” Acceptance criteria prevent misunderstandings by turning expectations into measurable statements.

Good acceptance criteria help you:

• Reduce risk: issues are found before operational reliance.
• Speed onboarding: clear tests shorten integration cycles.
• Support accountability: disputes become evidence-based, not opinion-based.
• Enable repeatability: you can re-test after upgrades or changes.

The goal is not to make acceptance paperwork heavy. The goal is to make compatibility provable and re-checkable.

Define the Scope: Interfaces, Not Just Systems

Interoperability is easiest to validate when you define it by interfaces. Instead of “the station interoperates with the spacecraft,” describe the specific boundaries where systems touch and information must be correct.

Common interoperability interfaces include:

• RF interface: frequency plan, polarization, bandwidth, modulation, coding.
• Timing interface: time tags, frequency stability expectations, Doppler handling approach.
• Control interface: antenna control, scheduling APIs, pass start/stop triggers.
• Data interface: file formats, packetization, metadata fields, delivery method.
• Security interface: authentication methods, authorization roles, audit requirements.

Writing acceptance criteria at the interface level keeps the scope manageable and makes it clear what must be tested end to end.

Acceptance Criteria Principles: Clear, Measurable, Repeatable

Acceptance criteria should read like testable statements. They should not rely on interpretation. A practical rule is that a third party should be able to run the test and reach the same pass/fail result.

Strong acceptance criteria typically include:

• Condition: what setup or scenario applies.
• Measurement: what you observe or record.
• Threshold: the numeric or categorical pass condition.
• Duration or sample size: how long it must hold, or how many passes are required.
• Evidence: what artifacts prove the result.

For example, “Successful contact” is too vague. “Carrier acquired within 30 seconds of AOS for 9 out of 10 passes, with continuous lock for at least 95% of each pass” is testable.

RF and Link-Layer Acceptance Criteria

RF interoperability proves that the station can acquire and maintain the signal in a way that supports stable demodulation. Even if decoding is handled elsewhere, you still want to establish that the RF chain is compatible with the spacecraft’s emissions and operational constraints.

Common RF acceptance criteria areas:

• Frequency accuracy: received carrier is within an expected offset window given Doppler compensation strategy.
• Polarization alignment: correct polarization selection and stable cross-pol isolation behavior.
• Signal quality: minimum C/N0 or Eb/N0 observed during the pass under defined conditions.
• Stability: lock maintained for a defined fraction of the pass, not just momentary acquisition.
• Interference tolerance: ability to identify and characterize interference events with recorded evidence.

RF acceptance criteria should account for pass geometry. A low-elevation pass is not the same as a high-elevation pass. Define the elevation range and expected performance bounds for the test set.

Baseband and Protocol Acceptance Criteria

Baseband interoperability proves that the receiver correctly reconstructs the bitstream and interprets framing and encapsulation as expected. This is where many “almost works” integrations fail: the signal looks good, but the data is not usable.

Acceptance criteria commonly cover:

• Demodulation lock: receiver achieves lock within a defined time and remains locked for a defined duration.
• FEC and decoding success: decoded frames meet expected error rates or thresholds.
• Framing correctness: expected frame sync and frame counters behave consistently.
• Protocol compliance: packet headers, sequence rules, and encapsulation match the agreed interface.
• Data completeness: expected volume or expected frame count is delivered per pass within tolerance.

If the mission uses multiple modes, acceptance should include tests for each operationally relevant mode. Otherwise, a “successful test” might only prove one configuration.

Operational Workflow Acceptance Criteria

Interoperability is not only technical. It also includes whether operations can run smoothly. If pass execution requires ad hoc manual steps, it may not be operationally compatible with the mission’s staffing or reliability needs.

Workflow acceptance criteria often include:

• Scheduling correctness: passes are generated and executed at the right times with correct parameters.
• Configuration loading: station profiles apply correctly and predictably for each pass.
• Automation behavior: alarms and exceptions trigger the right responses without creating noise.
• Pass reporting: summaries contain required metrics and timestamps consistently.
• Operator actions: any required human steps are documented, minimal, and repeatable.

Operational criteria should match the intended operating mode: manual, assisted, or lights-out. A station might be technically compatible but operationally incompatible if it cannot meet the expected staffing model.

Data Products, Metadata, and Delivery Acceptance Criteria

A ground station integration is not complete until the mission team receives usable data with the right context. That means correct files, correct metadata, and a delivery path that is reliable under real conditions.

Acceptance criteria for data delivery typically cover:

• Product format: output files match the agreed structure and naming conventions.
• Metadata completeness: required fields exist and are populated correctly.
• Time consistency: time tags and pass identifiers align with the mission’s expectations.
• Integrity checks: checksums match and corruption is detectable.
• Delivery performance: delivery occurs within a defined latency target for defined data volumes.
• Retries and partial delivery handling: the system can recover cleanly if a transfer is interrupted.

It helps to define what “done” means for delivery. For example, “file present” may not be sufficient if downstream systems need a completion marker or a manifest.

Security and Access Acceptance Criteria

Security acceptance criteria ensure that interoperability does not create unsafe access paths. This is especially important when multiple organizations share infrastructure or when remote access is required for operations.

Common security acceptance criteria:

• Authentication methods: required login methods are enforced for operator and admin access.
• Authorization roles: roles and permissions match job needs and prevent unnecessary privilege.
• Audit logging: access and configuration changes are logged with sufficient detail.
• Segmentation: mission systems cannot directly access control networks beyond defined interfaces.
• Credential handling: secrets are stored and rotated according to agreed practices.

Security criteria should include at least one negative test: proving that disallowed access is actually blocked, not just “not used.”

Resilience and Failure-Mode Acceptance Criteria

Systems rarely fail on schedule. Interoperability acceptance should prove that the system behaves safely and predictably when something goes wrong. This is where you validate alarms, fallbacks, and recovery steps.

Useful failure-mode acceptance criteria include:

• Backhaul outage behavior: data is buffered and delivered later without loss, or the system fails safely with clear reporting.
• Service restart recovery: critical services can restart without manual rework and without corrupting outputs.
• Partial pass behavior: short or degraded passes are handled with correct labeling and integrity indicators.
• Configuration rollback: known-good configurations can be restored quickly after a bad change.
• Safe transmission state: uplink capabilities do not become enabled unexpectedly.

These criteria help avoid the common operational problem where a system “works on a good day” but fails in confusing ways under stress.

Test Planning: How to Run a Credible Interoperability Campaign

Interoperability tests are more credible when they are planned as a short campaign rather than a single “demo pass.” The goal is to test across the conditions you will actually see in routine operations.

Practical planning steps:

• Define test cases: nominal passes, low elevation passes, mode changes, and delivery edge cases.
• Set sample size: enough passes to cover variance, not just one success.
• Control variables: document station configuration, spacecraft mode, and any known constraints per test.
• Decide pass/fail logic: thresholds for success rate, quality metrics, and delivery latency.
• Plan for re-test: specify how issues are fixed and how the test is repeated.

A campaign approach also improves trust. It shows that success is repeatable, not a one-time alignment of luck and attention.

Evidence Pack: What to Collect to Prove Compatibility

Acceptance is strongest when it produces an evidence pack: artifacts that demonstrate outcomes and allow later review. The evidence should be lightweight enough to collect routinely, but complete enough to support decisions.

Common evidence items include:

• Pass summary: AOS/LOS timestamps, acquisition time, lock duration, and key quality metrics.
• Configuration snapshot: station profile version, modem settings, and antenna tracking mode used.
• Quality logs: time series of key metrics such as C/N0, Eb/N0, or frame error indicators.
• Data integrity proof: checksums, manifests, completeness counts, and delivery confirmations.
• Exception records: alarms raised, operator actions taken, and resolution notes.

Evidence should be traceable. Each artifact should tie back to a pass ID and a time window so that results are not ambiguous.

Common Mistakes and How to Avoid Them

Many interoperability programs fail because criteria are incomplete or because tests focus on the easiest success case. The mistakes below are common and preventable.

• Testing only nominal passes: you miss the performance edges where most operational trouble occurs.
• Confusing RF success with data success: a visible carrier does not guarantee correct decoding or usable products.
• Ignoring failure modes: the system looks good until the first outage or restart event.
• No sample size: one good pass is not proof of repeatability.
• Unclear evidence: results cannot be audited later because artifacts are missing or inconsistent.
• Criteria that are too flexible: “acceptable performance” without thresholds leads to disputes.

A strong acceptance plan is balanced: it is strict enough to prove compatibility and flexible enough to reflect real-world variance.

Glossary: Interoperability Terms

Acceptance criteria

Measurable statements that define what must be true for a system integration to be accepted as working.

Interoperability

The ability of systems and workflows to work together reliably across technical interfaces and operational processes.

End-to-end test

A test that validates the full chain from acquisition through decoding, validation, and delivery.

Pass/fail threshold

A defined numerical or categorical condition used to decide whether a test case meets requirements.

Evidence pack

The set of artifacts collected during tests to prove outcomes, such as logs, configuration snapshots, and integrity checks.

Sample size

The number of passes or test repetitions required to demonstrate repeatability under real conditions.

Failure mode

A specific way a system can fail, such as loss of backhaul, loss of lock, or service restart during a pass.