The Common Data Link (CDL) Test Bed located at JITC is equipped with the appropriate CDL test tools and personnel to provide CDL Waveform Specification Compliance Testing and Certification. CDL vendors are charged a standard rate using a Standard Rate Schedule. This fee helps pay for the costs of the test, and includes maintenance and operation of the CDL Test Bed.
The Testbed provides:
- Greater access to test equipment by allowing developers and Program Managers (PM) access to the facility.
- Better cost effectiveness by allowing program managers and developers to share the testing costs.
- Resources for JITC to perform as airborne reconnaissance community independent waveform tester.
- Confidence for PMs and services that the data link has demonstrated a specific level of interoperability with legacy CDL equipment.
CDL legacy, migration, and future implementations are tested and verified in accordance with CJCSI 6212.01F. As a precursor to the interoperability test, a compliance certification test is performed. The objective of this test is to determine the degree of compliance to the CDL specification. CDL Systems need to accomplish as a minimum the following:
- Verify CDL is Compliant with Relevant CDL Specifications
- Certify Interoperability is Relevant to CJCSI 6212.01F
JITC conducts CDL compliance certification tests as laboratory tests. An RF cable connection between the system under test (SUT) and an external CDL PCE/SCE is used instead of an over-the-air RF transmission from antenna to antenna. The SUT is tested in the operational X / Ku band frequency ranges and at operational data rates but is not tested with sensor or processor interfaces. JITC can conduct the test in conjunction with developmental test events or can plan and conduct the test as a JITC-only test event.
Laboratory testing does not measure:
- Accuracy of the SND, antenna tracking, and Ranging. SND, antenna tracking, and Ranging are verified during operational tests or demonstrations
- FL/RL phase and amplitude. Vendor provides the CDL PM with verification that the FL/RL phase and amplitude imbalance meet the specification criteria.
JITC will use compliance verified CDL equipment, compliance validated CDL equipment tested by JITC with CDL systems that have demonstrated CDL compliance through operational or test bed use, or CDL test systems. These equipment and systems include but are not limited to the following CDL systems:
- Modularized Interoperability Surface Terminal (MIST), at L3 Communications
- Common Imagery Ground/Surface System (CIGSS) Testbed
- CDL Functional Tester (CDL-FT)
- CDL Test Terminals
- CDL Waveform Compliance Tester
Based on test results, analysts determine if the system complies with the current Waveform Specification for the CDL Segment, Specification. Where anomalies occur, analysts attempt to determine the operational impact.
JITC uses synchronization (SYNC) indicators to determine if specific digital processes are correctly operating. If SYNC indicators are not available on the SUT then JITC infers from a successfully established data link that specific digital processes are correctly operating. JITC conducts the compliance certification test in the following five phases:
- Phase 1. Modulation Off: Frequency counter used to measure accuracy of each unmodulated X/Ku-band FL/RL frequencies (carrier frequency uncertainty).
- Modulation on. A Spectrum Analyzer is used to observe center frequency signal for spurious signlas or in-band interference. JITC also determines whether the SUT transmitter meets the X/Ku band spectral emission requirement.
- Phase 2. Modulation On: External PCE/SCE connected to the SUT by RF cable to provide functional capabilities needed to test SUT. JITC observes and records data from FL and RL RF and digital functions to determine if the SUT performs the interleave/de-interleave, encode/decode, multiplex/de-mulitplex and EFC/EFD IDL and MIDL frame format functions. JITC observes, times, and records data to determine if FL/RL frequency change commands (5MHz steps) are executed and Pseudo-random Noise (PN) codes are resolved within the specified time criteria. A Clean link break test is performed to determine how long it takes the SUT to require the link after the FL transmit is turned off for a specified period of time. JITC tests the capability of the SUT to maintain EFC sync when the CWCT transmitter (FL) carrier frequency and symbol clock are adjusted to simulate motion.
- Phase 3. JITC uses the CWCT to internally generate a BER Test to measure BER on the SUT channels and performs a Packet Loss Ratio test to verify ATM/Ethernet network functions.
- Phase 4. SND and EFC/EFD Real Time / Ground Station Coordinate changes and link audio functions: JITC uses the CWCT to encode and decode Standard Navigational Data, verify real-time ground coordinate change commands. JITC uses headsets with microphones connected to the SUT to test audio (voice) quality of the full-duplex link.
- Phase 5. Encryption/Decryption: JITC observes and records data during COMSEC power interrupt and bypass test to evaluate cryptographic key retention and the COMSEC bypass function. JITC uses CWCT to internally generate a BER Test to measure encrypted BER and/or packet loss ratio to verify ATM/Ethernet network functions.
CDL CERTIFICATION PROCESS
The CDL certification process is initiated at the request of a PM or Vendor and is based on the CDL Waveform Specification criteria. The CDL Team coordinates the following:
- Assist Program Managers throughout the life cycle with System Development and Achieving DoD/Office of the Secretary of Defense (OSD) Interoperability Goals.
- Review requirements documents, test plans and test reports.
- Coordinate test requirements and test opportunities with PMs, testers, developers, vendors, and user representatives as appropriate.
- Develop and coordinate test plans to ensure specification/standards compliance and interoperability requirements are fully integrated with CDL test events.
- Conduct specification/standards compliance and interoperability testing of CDL Migration and Legacy Systems.
- Process test data and present the data in a form consistent with JITC reporting requirements/procedures.
JITC issues a CDL Compliance Certification Letter based on a successful compliance test or approved waivers. The Compliance Certification Letter with Test Summary enclosure will be distributed to all concerned. Compliance Certifications are good for three years unless major changes are made to the system. At the end of the three years, a desktop analysis is conducted to determine if retesting is necessary. If not, a letter is issued for another three year period. All Compliance Certification Letters are placed on the JITC CDL Web Page Registry.
CDL ASSESSMENT LETTER AND TEST SUMMARY
If the system is not CDL compliant and requires a waiver or retest a JITC CDL Assessment Letter with enclosed Test Summary is issued 30 days after completion of testing. This letter is sent to the PM or Vendor stating the system is not compliant with the CDL Waveform Specification and identifies possible waiver requirements. The PM or Vendor requests a waiver for the non-compliant criteria through their service CDL representative, who provides an endorsement or rejection, to the CDL Working Integrated Product Team (WIPT). If the CDL WIPT approves the request for waiver of non-compliant criteria an approval letter is forwarded to JITC and JITC changes the compliance assessment to a compliance certification and prepares a Compliance Certification Letter for the PM or Vendor.