 Micrologic Vehicle Tracking System |
 |
| The main components of the MVTS Mobile Unit are the GPS receiver, Sensors, Memory Module and Communications module. These are all interfaced to a microprocessor-based controller and housed in a single, rugged tamper-proof enclosure. |  |
The GPS receiver processes signals from the U.S. Navstar satellites and generates the position information of the vehicle in the form of coordinates. Being a civilian application, the accuracy is intentionally degraded by the U.S. government to 100 meters. However, with the optional use of Differential GPS it is possible to achieve accuracies of less than 5 meters. In most applications, such high accuracy is not necessary although the user can always avail of this option for a very reasonable price. Some of the features of the MVTS GPS receiver are:
 |
Uninterrupted
operation in urban areas with high rise buildings |
|
Uninterrupted
operation in areas with extensive foliage |
|
Fast
start time of less than one minute |
|
Reacquisition
time of only 100 milliseconds in case contact with the satellites
is momentarily lost |
|
Built-in differential GPS capability |
In addition to position and time information, the MVTS mobile unit has built-in sensors that can detect or measure the following:
|
Vehicle
speed |
|
Emergency
buttons |
|
Altitude |
|
Engine
status |
|
User-defined detectors |
All these data are automatically captured in a memory module which uses non-volatile memory devices. The module can be unplugged at the end of the trip and the data downloaded to a PC by plugging to the PC's serial port. This means that the MVTS can also be operated in off-line mode in case there is no need for real-time monitoring. Shipping and Public Bus systems are applications which can still benefit from the MVTS even without real-time monitoring.
The mobile unit is also equipped with an alphanumeric LCD display to facilitate monitoring of the unit's operation and for diagnostics purposes.
For communicating with the Central Monitoring Station, there are three options:
|
VHF/UHF Radio Modems - These are data grade radios and modems operating at frequencies allocated by authorities to the user. The typical transmission speed is 19.2 kbps and the range without repeaters vary from 10 to 40 km depending on the nature of the terrain. For greater distances the user has to set up its own infrastructure of re-peaters or interfaces to public carriers in the various localities of operation. |
|
Trunk Radios - These are usually voice grade radios operated by a public carrier. The area of coverage can be several cities or even the whole country. Charges are fixed on a monthly basis but being voice grade, transmission speed is very slow, usually 1200 bps. |
|
GSM Cellular - a digital cellphone system can provide almost unlimited geographic coverage. Transmission speeds of 14.4 kbps are possible but communications costs can escalate since charges are time-based. |
For applications involving hundreds or thousands of vehicles operating in a citywide area, such as public transports or police, the radio modem option is ideal. It provides the fastest response time of the three and as many as 200 mobile units can be accomodated on one frequency with a maximum scanning time of only 30 seconds for all the 200 units. There are also no monthly communications charges.
For fewer vehicles or applications where response time is not critical, the trunk radio is suitable, especially if the coverage has to extend into other cities. The advantage is that the user does not have to deal with the headaches of operating and maintaining his own radio network.
If the application requires very wide coverage, such as the whole country, and/or the location updates do not have to be frequent, then the GSM option is ideal. Examples are shipping, provincial bus and surveillance applications. Some cellular phone companies offer wholesale discounted rates or fixed monthly charges for special applications like vehicle tracking. In this case, even applications requiring frequent up-dating may be feasible.
Specifications of MVTS Mobile Unit
| GPS Receiver: | ||
| L1,
C/A code 12 channels Cold Start: 40 seconds Hot Start: 8 seconds Reacquistion Time: 100 ms Differential GPS capability |
||
| Position Accuracy: | ||
| 100 meters 1 - 5 meters with DGPS option |
||
| Memory Module: | ||
| 256 Kb
capacity non-volatile RS232 serial interface (DB-9) Waterproof casing 25 mm (H) x 62 mm (W) x 92 mm (D) |
||
| Sensors: | ||
| Standard - | Vehicle
speed 2 Emergency buttons |
|
| Optional - | Engine monitor Altimeter Power supply voltage monitor 3 General purpose inputs 0-5 VDC |
|
| Display | ||
| Dot
Matrix LCD 2 x 16 characters with backlighting |
||
| Communications: | ||
| Radio Modem Option | ||
| Operating
frequencies: 132 - 208 Mhz 380 - 520 Mhz 928 - 960 Mhz 300 - 19,200 bps Transmit power: 100 mw to 5 watts Receive sensitivity: -103 dBm 6.25-12.5 khz narrow band operation |
||
| Trunk Radio Option: | ||
| Bell 202
Protocol 300 - 1200 bps Optional voice operation Radio transceiver to be provided by trunk radio operator |
||
| GSM Option: | ||
| GSM 900
Phase II 2400 - 14,400 bps Transmit power: 2 watts Receive sensitivity: -108 dBm Optional voice operation |
||
| Power Supply: | ||
| External: | 10 - 14 VDC Unregulated | |
| Internal: | 9 VDC NiMh rechargeable back-up battery | |
| Weight: | 2 Kg max. | |
| Enclosure: | Aluminum 60 mm (H) x 200 mm (W) x 165 mm (D) | |
| Environmental: | ||
| 0
to 50 deg. C 90 % Relative humidity 9 G's |
||
"Innovative Technologies for Transportation and Utility Industries"