DataLink Systems has partnered with Wyless for school bus tracking
GPS location reporting over Kenwood LMR Networks
Much has been said about GPS reports choking the control channel. This is a reality when a mobile radio is programmed with "time slot" GPS updates. As an example, if 200 School Buses are programmed to send GPS reports every two minutes using time slot control, there would be a GPS TX every 0.6 seconds, this would result in control channel overload. One alternative is to assign one or more channels for data processing only. Another is to use GPS and Internet routing to steer NX radios off a trunked network and on to a conventional channel to send GPS and other data.
Trunked versus Conventional for GPS and other data reports
Sending GPS reports over a trunked network is very inefficient. One GPS transmission requires around 1000 milliseconds of channel time. To send the same report over a trunked network will tie up a channel for one to two seconds. When a high number of School Buses have to be GPS tracked and there are only a small number of channels available the most efficient approach calls for remote fixed site radios in conventional mode and connected to a local Internet node, routing GPS data directly to a processing hub such as DataGate, thus bypassing the trunked network completely. Those radios can be part of a trunked remote site and normally operating in a trunked mode, but also scanning the conventional channel. When activity is detected on the conventional channel the data is routed over the Internet to the central DataGate hub. The Datalink i50 MobiHub (required for School Bus tracking) has the ability to use GPS site location information to steer the NX radio to the correct channel.
Network Routing Capacity
Most School Bus authorities want to get GPS location updates every one or two minutes and this creates a burden for trunked networks. The following gives an estimate of how many School Buses can be monitored over a selected system.
A: Standard trunked network = 100 +/- Buses.
B: Separate conventional/Internet network = 500 +/- Buses.
C: Dual networks (LMR + GPRS) = Unlimited.
A dual network is simple to set up and operate. The Datalink i50 MobiHub is the "smart box" with internal GPS receiver which would be installed in each School Bus and connected to the data port on the NX radio. The i50 MobiHub is also connected to the various sensors attached to warning lights, stop arms, doors etc. All the sensor reports are then routed over the network to a DataGate processing hub and relayed to a host program such as Edulog. For dual network operation, the Datalink i50 MobiHub is supplied with an internal GPRS modem. Any Kenwood Dealer can add GPRS service by contracting with Wyless for SIMs and airtime. Estimated Dealer cost per month for GPRS service per Bus would be under $10.
Wyless GPRS
(USA only)
Datalink has partnered with Wyless, a national provider of M2M GPRS data services based on the T-Mobile network footprint. When a large number of School Buses have to be monitored, a "dual network" solution is the answer. This results in all voice traffic using the NEXEDGE network and data being routed over GPRS.
Edulog
Datalink has teamed up with Edulog, a leader in School Bus GPS tracking and information processing to deliver a complete "end to end" School Bus tracking and monitoring solution for Kenwood Dealers to offer to their local School Bus transportation authorities. Kenwood Dealers should contact Edulog directly for more information.
For more information on Datalink’s i50 MobiHub and DataGate software routing hub contact Datalink.
