OmniAir Certification Services, Inc. is an independent, non‐profit organization chartered to develop certification programs for the transportation industry for technologies used in the Connected Vehicle community. OCS works at the request of user groups – state facility operators, airport authorities, tolled facilities and technology consortia. The first OCS test program developed was created at the request of the “6C Toll Operators Committee”, or 6CTOC, a user group wishing to deply toll systems based on the ISO 18000‐6c protocol. OCS develops certification programs for any technology requested by a user group. This also includes the potential for developing multi‐protocol testing programs. The goal of OCS certification is to ensure that OCS‐certified devices & systems are interoperable and perform according to requirements established by user groups. Devices must pass a series of rigorous tests in order to obtain certification.
As referenced above, OCS’ first program was developed for users in the toll community. While tolling is no stranger to testing, the OCS program is different from other testing programs in several ways. First, the OCS 6C program was driven and informed by toll operators, users and manufacturers. The ‘6C Certification Program’ was informed by ‘6CTOC’ a group of operators including E‐470 PHA, SRTA, WashDOT and UDOT. They provided requirements and were involved in all aspects of the program.
A second key difference is that OCS testing is based on open standards and certification programs are based on best test practices as established in other industries including:
- Accreditation and auditing of independent test laboratories;
- Commercially‐available test tools that offer automated testing; and,
- Recognition of already‐established certification programs
- Certification conducted on‐demand (when a product is available) rather than via test events that are less often, less rigorous and much less standardized.
The broad use of common and open test standards, tools and test methods permits OCS rapid and efficient adoption of other protocols into the certification program.
OCS testing is conducted by OCS‐Accredited Test Labs following ISO standards for lab auditing and accredidation. An independent lab has to implement ISO 17025 quality system and use qualified test equipment to ensure accuracy and consistency of test results. In addition, it has to prove it can accommodate the protocol and test/verify user requirements of the technology. After testing is complete, the lab reports results to the OCS Board, a group of experts in the highway operating and testing communities. The Board grants (or denies) the applicant the certification awards for the submitted device.
The OCS testing approach is straightforward – a protocol is based upon a standard and evaluated against its requirements as defined by a user group / client. The first protocol for which OCS testing services were requested is based on the ISO 18000‐6 Type C standards (also known as “ISO‐6C” or just “6C”). This standard was developed by EPCglobal and adopted by ISO. It covers UHF radio spectrum available globally. The 6C standard was designed with security and performance from the start and has been implemented in many industries, constantly evolving while preserving backward compatability.
Any organization – be they a manufacturer or user group with technology (a transponder, reader/interrogator, etc) that implements to a standard may apply to OCS to be tested and certified.
The OCS Certification approach follows an established and proven path to interoperability. It consists of 4 stages of testing: Conformance, Baseline Interoperability, Environmental Testing and Performance Testing. The first three are conducted in a laboratory environment.
A device has to past all tests in the first two stages before it can participate in Environmental and Performance testing. This approach has several advantages:
- Devices are proven to be interoperable in laboratory conditions;
- If any issues arise they can be addressed at the root level;
- Devices will work in the targeted operating climate, and;
- Application‐specific testing can focus on performance rather than interoperability.
In contrast, other test approaches have not standardized the lower levels of testing (see right) and therefore they require clients to focus scarce resources on conducting extensive performance testing to achieve interoperability (aka “shoot‐outs”). This approach may be sufficient in a single source environment but is not suitable or scalable to multi source environments.
OCS Testing in Detail (using the 6C program as an example)
OCS testing follows proven approaches commonly used in other mature industries such as supply chain management, broadband and the telecommunications.
- Conformance (OCS‐administered outside of OCS by EPCglobal or MET Labs).These tests ensure that a device has implemented all functions correctly. Both radio and protocol commands are tested. For example, tests verify that a tag responds in the correct amount of time to a reader command. These tests also ensure that a reader will not interfere with other readers by virtue of meeting multiple or dense interrogator masks. A device has to pass all tests at this level to obtain certification. A sophisticated test apparatus developed by National Instruments can prove beyond any doubt whether a device conforms or not. OCS recognizes EPCglobal or ISO certifications (such as from MET Labs) for this level.
- Baseline InteroperabilityThis series of tests ensures that a reader and tag seamlessly communicate with each other as they would in a tolling environment. Test cases verify that a) a single tag can be inventoried when in a population of tags, b) the memory content of a tag can be read, and c) data can be written to a tag and protected from unauthorized reads. The tag is eventually ‘killed’ by a reader command. If a tag is submitted for testing, qualified readers are used. If a reader is submitted, qualified tags are used. Qualified tags and readers go through intensive testing and are selected based on passing all conformance and baseline interoperability tests. A tag‐reader pair will go through 300 test cases. A device has to pass all tests at this level to obtain OCS certification.Device vendors need to correct the problems before they can proceed with other certification tests. The OCS Test approach ensures that resources are not wasted on testing readers that interfere with other readers or violate command protocol, or tags that cannot respond quickly enough to a reader or cannot write properly to a user memory. OCS recognizes EPCglobal or MET Labs certifications for this level. On average, over 50% of tags and readers fail Conformance or Baseline Interoperability.
- Environmental Testing (Applied Interoperability)These tests determine if a device can function in a specifically‐configured tolling environment. The device is subjected to the following tests, each lasting a week or longer: a) Temperature (‐40 to +85 degrees Celsius); b) Humidity (95% Relative); Ultraviolet Light (UV); and, d) Infrared Light (IR). Tests are based on 6CTOC requirements and reflect established telecommunications industry and/or military testing standards. A failure of any test does not preclude a device from being certified. A point of the last successful condition will be recorded (i.e. a device that worked up to 80°C) and the report is available to operators who may not need the technology to meet that specific requirement. OCS may recognize and select equivalent pre‐existing certifications on specific elements of the device’s performance conducted a priori by a recognized laboratory.
- Performance Testing (Applied Interoperability)
This testing most resembles the toll industry’s “shootouts” approach and is conducted on standard tolling roadside infrastructure. Tests are conducted using a typical sedan and SUV. A reader antenna is placed on a gantry at a specific angle per manufacturer recommendations. An RFID read zone for a reader antenna is determined (indicating maximum read range, RFID field strength and other parameters). This setup helps determine the exact location of the first and last reads and establishes the RF footprint.
A tagged vehicle travels through a toll point at various speeds (up to 85mph). The total number of reads is recorded for each configuration of tag height & orientation (i.e. angle), and vehicle speed. Testing is performed on a sedan and SUV. For each configuration, 128‐bit user memory is verified that it was successfully written. Testing is also performed to verify the tag can be read at the maximum read distance for each tag configuration. As an example, if the maximum distance is 7 meters for a particular reader antenna configuration (i.e. elevation and angle) then the ability for the reader to correctly read a tag on a vehicle travelling at 85 mph, 7 meters away, is verified. Depending on how the antennas are setup, testing verifies that a vehicle in an adjacent lane cannot be read.
The above tests are repeated at high speed for a convoy of cars to ensure that a reader can handle multiple read/writes in this common‐to‐tolling situation.
These tests are based on 6CTOC field requirements which are protocol‐independent. As in the Enviromental level, a failure of a particular test here does not preclude a device from being certified. A device that worked up to 65mph may still be acceptable to an agency in, say, Delaware.