When Radio is the Answer

Many smaller, less wealthy school districts think GPS tracking is too expensive or too complicated for their own use. What they may not realize is it may be possible to implement low-cost GPS/AVL products into their existing radio infrastructure without any additional monthly or recurring costs.

The Holly Area Schools in southeast Michigan near Detroit recently installed a mobile radio type GPS/AVL product in their fleet of 50 buses. The radio shop, Electrocomm-Michigan, Inc., proposed the combination of a GPS/AVL unit that interfaces with a separate mobile radio to provide all GPS updates and messaging on a stand-alone radio channel.

This solution was particularly attractive to the district as it owned its own radio tower, base station and mobile radios. The only additional hardware items required were a separate antenna for the radio and GPS receiver and the AVL hardware for each bus.

By foregoing the mobile radio used for voice traffic already installed in the bus, the school district dedicated the transmission path for data only, according to Paul Wardner, technical sales manager for Pyramid Communications. The combination GPS/AVL unit and mobile radio was mounted in the overhead access panel on many buses or behind a dash panel, as available, for ease of installation. The same product used in this application can be used on radio systems where the voice channel is shared with the AVL device. A feature called “queuing” stores up GPS position updates then sends them in a batch. This reduces the data transmissions and provides recording of all updates to give the same GPS resolution.

Back at the bus garage, a second antenna was installed onto the district’s existing tower to provide the same coverage as the voice radios. A dedicated radio is used with the base modem that connects to the PC running the mapping software.

The installed AVL product has the ability to provide GPS updates “on-demand” when an input is triggered. For this application, the one input was wired to a switch that indicated if the front door was open or closed and a second input was used to report if the warning lights were active. This gives the mapping software additional information to be recorded, such as the bus location when the entry door is opened or closed and when the warning lights are activated. Recorded information can prove to be very useful when a parent calls in to find out if the bus stopped at a pick-up point, and it provides “proof-of-service” to the parent if the child was late to the bus stop. School districts also benefit from knowing when the bus delivers the students to the schools. If the students arrive early, there may not be teachers “clocked-in” for proper supervision. If the students arrive late it affects the attendance and interrupts the classroom session.
By using a dedicated radio channel or even if using the existing radio network, the add-on GPS/AVL unit requires no monthly service charges. It adds value to a resource that is already on the bus or allows a low-cost radio solution to be added to provide a whole set of tools for bus fleet management.