Making Tracks With the MTA
The MTA is installing the tracking capabilities as part of Phase I of its Service Management and Customer Information System (SMCIS) deployment, which is slated to cost around $7.2 million, and due to be in place by the end of this year.
In the first phase, Siemens VDO is installing the wireless LAN tracking equipment at the 126th Street terminal, and souped-up GPS tracking, and display units on over 100 vehicles at the depot.
The system is designed to enable MTA users to centrally check that a vehicle is on the right part of its route at the correct time and receive any urgent data from the bus in real-time.
Dave Behmer, director of sales and marketing at Siemens VDO says that the company is using existing MTA infrastructure for real-time data transmissions. "We're using their private voice system," he says. "We pulled several of the channels and converted them for data."
Siemens has also developed a GPS system that allows the bus to be tracked around the city. This can be difficult with traditional satellite positioning because such receivers need a clear view of the sky to accurately triangulate its position. Tall buildings can block such sightlines and in places like Manhattan, create urban canyons.
To circumvent that, the Siemens unit has developed a system that grabs the last available GPS reading, then using an odometer and a gyro in the vehicle, plots how far and in which direction the bus is traveling on a computerized map, until the bus gets another satellite fix.
Behmer claims that this "patented dead reckoning" is more accurate than the other many forms of assisted GPS technology. (See Zeroing In on Rosum.)
The Siemens system is also being used to make automated announcements to passengers on the bus as it makes its way around the route.
When the buses are back at the depot, "non-critical" data from the day's drive can be downloaded over WiFi.
This can be used by the MTA to quantify how many riders use a particular route and what the traffic is like in that area.
— Dan Jones, Site Editor, Unstrung