RTMS® G4™ is a miniature radar operating in the 24 GHz microwave band, employing the FMCW (Frequency Modulated Continuous Wave) principle. It transmits a low-power microwave signal of constantly varying frequency in a fixed fan-shaped beam.
The beam "paints" a long elliptical footprint on the road surface. Any non-background targets will reflect the signal back to the RTMS where the targets are detected and their range instantly measured.
The RTMS range measurement resolution of 0.4 metres (1.3 ft.) allows the "slicing" of the footprint ellipse into 256 range-slices. The user can define a number (1 - 12) of detection zones, each consisting of multiple range slices, and usually covering a single lane.
The RTMS internal microcomputer controls in real time 16 opto-isolator relays corresponding to the detection zones. Relay contacts are closed when a target is present within the respective detection zone. The contact-pairs can be connected directly to traffic controllers. In addition, short-term statistical data on each zone are accumulated and transmitted by the RTMS via its serial port. Typically, every 30 to 300 seconds, a message containing the volume, occupancy, average speed and classification by length data in each detection zone is transmitted and/or collected in the sensor memory.
The long microwave wavelength and the range-measurement capability make the RTMS immune to all weather effects (including rain, snow, ice, strong winds and vibrations) and to most occlusion situations allowing vehicles hidden behind other vehicles to be detected.
The carefully engineered antenna beam shape, afforded by a flat patch array, ensures sufficient elevation coverage for either zero setback operation, as required in urban traffic control, or for 12 lane footprint required in highway traffic monitoring. At the same time, it is not too wide to minimize transmitter power waste, maximize interference rejection and avoid reflections from overhead tram cables and acoustic walls.
The transceiver is stabilized by a patented digitally generated modulator that ensures high efficiency and results in very low power consumption, as required by solar and battery powered applications.
The patented G4 enclosure is specially designed to achieve maximal protection of the electronics against water penetration and humidity, while allowing the user easy access for hardware upgrades. The enclosure presents a reduced wind-load for operations in severe storms and heavy rain.
The all-in-one concept of G4 permits all power and communications options to be contained within the detector unit, thereby eliminating the need for additional cabinets for power supplies, radio modems, contact pairs and other interfaces. This saves cables, connectors and obviates field integration time.
The new WinRTMS setup software, with its user friendly graphic user interface, is designed for high visibility even in bright sunlight and allows either mouse or keyboard control. The software permits automated lane and speed calibration, manual verification of all parameters, self-test, firmware upgrades and setup of all internal communications equipment.
RTMS G4 lane calibration is performed using a patented wizard that automatically detects the presence and location of travel lanes. The wizard allows user confirmation of the lanes of interest prior to final setting of lane boundaries to allow maximum flexibility in the setup process.