Wavetronix SmartSensor HD - Introduction; What youll need

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SmartSensor HD
• A timestamp that records the year, month, day, hour, minute, second and millisecond of the time the vehicle left the detec-
tion zone
• Lane assignment
• Speed values in either mph or kph
• Vehicle length
• Classication using up to eight user-dened classes
• Range
e real-time true presence data packet protocol shall support:
• Sensor ID
• True presence information for each lane being monitored
10.0 Data Buering. e RVSD shall store, in non-volatile memory, at least 9,000 interval data packets with the maximum num-
ber of lanes and approaches congured and all interval elds enabled.
e RVSD shall timestamp interval data using a real-time clock that maintains accurate time even when power is disconnected
from the sensor for extended periods of time.
11.0 Radar Design. e RVSD shall employ a dual radar design that includes two receive channels.
In order to achieve accurate per vehicle speed measurements, two radar channels are necessary so that a speed trap–type speed measurement
can be made.
11.1 Frequency Stability. e circuitry shall be void of any manual tuning elements that could lead to human error and
degraded performance over time.
All transmit modulated signals shall be generated by means of digital circuitry, such as a direct digital synthesizer, that is
referenced to a frequency source that is at least 50 parts per million (ppm) stable over the specied temperature range, and
ages less than 6 ppm per year. Any upconversion of a digitally generated modulated signal shall preserve the phase stability
and frequency stability inherent in the digitally generated signal.
is specication ensures that, during operation, the RVSD strictly conforms to FCC requirements and that the radar signal quality
is maintained for precise algorithmic quality. Analog and microwave components within an RVSD have characteristics that change
with temperature variations and age. If the output transmit signal is not referenced to a stable frequency source, then the RVSD is
likely to experience unacceptable frequency variations which may cause it to transmit out of its FCC allocated band and thus will be
non-compliant with FCC regulations.
e RVSD shall not rely on temperature compensation circuitry to maintain transmit frequency stability.
Temperature-based compensation techniques have been shown to be insucient to ensure transmit frequency stability. One reason
this type of technique is not sucient is that it does not compensate for frequency variations due to component aging.
e bandwidth of the transmit signal of the RVSD shall not vary by more than 1% under all specied operating conditions
and over the expected life of the RVSD.
e bandwidth of an RVSD directly aects the measured range of a vehicle. A change in bandwidth causes a direct error in the
measured range, i.e., a 5% change in bandwidth would cause a range error of 10 ft. (3 m) for a vehicle at 200 ft. (61 m). If the
bandwidth changes by more than 1% due to seasonal temperature variations and component aging, then the RVSD will need to be
frequently recongured to maintain the specied accuracy.
11.2 Antenna Design. e RVSD antennas shall be designed on printed circuit boards.
Printed circuit board antennas eliminate the need for RF connectors and cabling that result in decreased reliability. Printed circuit
antennas are less prone to physical damage due to their extremely low mass.