The Government of India felt the need for a permanent agency to expedite the publication of standards
and development of test facilities in parallel when the work on the preparation of the standards is going on, as the development of improved safety critical parts can be undertaken only after the publication of the standard and commissioning of test facilities. To this end, the erstwhile Ministry of Surface
Transport (MoST) has constituted a permanent Automotive Industry Standards
Committee (AISC) vide order No. RT -11028/11/97
MVL dated September 15, 1997. The standards prepared by AISC will be approved by the permanent CMVR
Technical Standing Committee (CTSC). After approval, the Automotive Research Association of India
(ARAI), Pune, being the secretariat of the AIS Committee, will publish this standard.
Intelligent Transport Systems (ITS) are globally proven systems to optimize the utilization of existing transport infrastructure and improve transportation systems in terms of efficiency, quality, comfort and safety. Having realized the potential of ITS, Government bodies and other organizations in India ar
e presently working towards implementing various components of ITS across the country.
INTELLIGENT TRANSPORTATION SYSTEMS - VLT WITH AN EMERGENCY SYSTEM
Requirements on ITS devices and functions - Vehicle Location Tracking and Emergency Button
For the purpose of this standard, definitions are given below:
refers to the minimum signal level at which the
device is able to successfully perform a cold start TTFF. The acquisition
sensitivity test is a simulated signal test.
"Assisted GPS (A -GPS)" is a system allowing satellite receivers to obtain
information from communication network resources to assist in acquiring
- GPS system is especially useful when the receiver is in a location where it is difficult for the satellite signals to penetrate. In addition to providing better coverage,
- GPS also improves the start - up time, which is the time required by the satellites and the receivers to establish a reliable connection.
"Circular Error Probability (CEP)"
is defined as the radius of a circle centered on the true value that contains 50% of the actual GPS measurements. So a receiver with 5 meter CEP accuracy will be within 5 meter of the true measurement 50% of the time. The other 50% of the time the measurement will be in error by more than one meter.
"Dilution of Precision (DOP)" is the degree of proximity of the location data to their mean value. The relative position of satellites affects the accuracy of location calculation by the locating module. Location coordinates computed when the satellites are clustered together suffer from dilution of precision (DOP), a factor that multiplies the associated errors. The DOP for an ideal satellites constellation arrangement equals close to 1, which does not magnify the underlying errors.
"Distance Root Mean Square (DRMS also called RMS, 1Sigma)"
This is computed as square root of the average of the squared horizontal position errors with 65% probability. The position expressed has the probability of being within a circle with radius with 65% probability. A locating module with 6 metre DRMS accuracy would be within 6 meters of its actual position 65% of the time.
"Emergency Button" A button provided in vehicle for passengers or crew members to send specialized data packet /SMS to Centralized regulatory server to indicate safety/panic situation caused by human or natural disaster or vehicle accident etc.
"Global Positioning System (GPS)" is a space - based radio navigation system. It provides positioning, navigation, and timing services to military and civilian users on a continuous basis.
"Sensitivity "refers to the minimum signal strength level at which locating module can successfully perform a location fix. A GNSS locating module has two different sensitivity levels – acquisition sensitivity and tracking sensitivity.
"Time to First Fix (TTFF)" describes the time required for a tracking device to acquire adequate satellite signals and related data (almanac and ephemeris data) to compute location.
"Tracking Sensitivity" refers to the minimum signal level at which the device is able to successfully maintain the location fix. The acquisition sensitivity test is a simulated signal test.
"Vehicle Location Tracking (VLT)" device uses satellite based location technology to determine and record
the precise location of a vehicle at regular intervals. The location data so determined can be stored within the device, and/or can be transmitted to the Backend Control Centre using a wireless communication modem built in the device.