1、164 STD-ITU-R RECMN fl-2307-ENGL 2997 4855232 0532563 528 Rec. ITU-R M.1307 RECOMMENDATION ITU-R M. 1307 AUTOMATIC DETERMINATION OF LOCATION AND GUIDANCE IN THE LAND MOBILE SERVICES (Question IT-R 51B) (1997) Summary The ability to automatically determine location and to provide guidance has become
2、increasingly important over at least the last decade and a half. This trend is likely to continue, if not accelerate, in the land mobile services. Further, various automatic determination of location and guidance (ADLG) techniques promise to play a major role in the Transport Information and Control
3、 System (TICS). This Recommendation presents a general overview of ADLG as well as technical information and examples of existing systems. The IT Radiocommunication Assembly, considering a) that automatic determination of location (ADL) will become an important part of many types of land mobile syst
4、ems, particularly, but not limited to, dispatch systems and public safety systems; and other types of systems such as tracking of objects or wildlife, and search and rescue; b) that the introduction of ADL into dispatch type systems can potentially improve spectrum utilization efficiency of communic
5、ations channels due to reduction in voice traffic related to location and routine information; c) that one of the most critical elements in dispatch service is the knowledge of current accurate location of every unit in the operational fleet; d) e) messages; f) operations; g) saving lives and protec
6、ting property; h) of an object; j) distress situations; k) 1) m) that costs of running land mobile dispatch operations are increasing; that a considerable part of the voice communications on a radio dispatch channel is location and other routine that ADL integrated with a land mobile radio dispatch
7、system can potentially reduce the cost of dispatch that accurate information on the location of units in a public safety operation can increase the potential of that ADL techniques may be of great value for non-dispatch type systems which involve tracking the location that ADL may be used to locate
8、people or vehicles travelling off-road routes or in wilderness, particularly in that within the land mobile service there is growing demand for guidance systems; that both ADL and guidance systems may use the same basic techniques for location; that guidance systems can potentially reduce journey co
9、sts and improve road safety; n) System (TICS), that both ADL and guidance techniques may be key elements of Transport Information and Control recommends 1 that ADL include the determination of location of all animate and inanimate objects, and messaging associated with the location or monitoring of
10、the given object. Such messaging may consist of voice or non-voice communications necessary to provide accurate, timely and complete status and instructional information relating to the object (or vehicle) being located or its occupants; STDoITU-R RECMN M.3307-ENGL 3997 485523i2 0533564 464 Rec. ITU
11、-R M.1307 165 2 operations; that interconnection with the public switched telephone network (PSTN) be limited to store and forward type 3 service. that the following broad operational requirements be considered when implementing ADL in the land mobile 3.1 Positional accuracy For many services, accur
12、acy to be provided is of the order of 100 m. In the public safety service, such as police, accuracy of the order of 10 m may be required. For other users (e.g. large area trucking and similar dispatch), an accuracy of about 1 km could be adequate. When systems such as tag readers are employed, as in
13、 bus and train routes, accuracy of 1 m may be achieved. 3.2 Updating position The frequency of position update transmissions will depend on the specific application. For vehicles requiring quick deployment in limited areas (e.g. police, fire tenders, ambulances), a frequency of updating of approxima
14、tely once per minute may be necessary. For dispatch operations over larger areas or defined routes (e.g. trucking, omnibuses, taxi, trains, or wildlife tracking), much less frequent updating is required. 3.3 Coverage area For many systems (e.g. police, fire, ambulance, passenger omnibus, taxi) opera
15、tional areas up to 100 km x 100 km are common. Some operations are confined to much smaller areas of up to 10 km; others may require national or regional coverage; 4 that ADL systems should be used to achieve the following benefits: 4.1 In fixed route operations: - - - - improved on-time service; -
16、- - reduction in checking and control personnel; more even distribution of passengers between vehicles; reduction in lay-over time resulting in reduction in number of vehicles and personnel; improved efficiency of response during emergency and dispatching a replacement vehicle; increased passenger l
17、oads due to more convenient and up-to-date location information being available to the public; economic benefits accruing from improved fuel efficiency and all of the improvements listed above; 4.2 In random route operations: - - - reduction of unnecessary travel; - - reduction in response time to e
18、mergency and service calls; reduction in the number of vehicles while maintaining the same coverage area; economic benefits accruing from the above; possible improved chances of success in search and rescue operations at remote locations; 4.3 - - location of stolen vehicles; - In other types of oper
19、ations: scientific uses such as wildlife tracking; increased efficiency of certain manufacturing processes, such as assembly line quality control; 5 need for voice communication to provide location information; that ADL systems should be used to improve spectrum utilization efficiency by reducing or
20、 eliminating the STD-ITU-R RECMN M-3307-ENGL 3997 4855232 O533565 3T0 166 Rec. ITU-R M.1307 6 6.1 Multilateration systems: that the following ADL techniques could be used in the land mobile services: - hyperbolic, - - differential-GNSS; 6.2 Non-multilateration systems: Global Navigation Satellite Sy
21、stem (GNSS), - proximity, - dead reckoning, - satellite, - homing beacons, - combinations of the above; 6.3 6.4 Links: Combinations of multilateration and non-multilateration systems; - - - A brief description of each ADL technique is given at Annex 1; 7 a forward link is any signal transmitted to a
22、 mobile unit to be located by a multilateration system, a reverse link is a multilateration signal transmitted to the fixed or base station, a communication link is used for two-way messaging in multilateration systems. that the following navigation systems could be used within land mobile service a
23、pplication: - - Loran-C; GNSS (Global positioning system (GPS), GLONASS, etc.); 8 examples of three such systems given in Appendices 1,2 and 3; that examples of parameters which may be useful for international standardization, can be found in the 9 that guidance systems can provide savings of journe
24、y costs by reducing travel time; 10 that the following guidance systems could be used in the land mobile services: - autonomous systems, - infrastructure supported systems, - dual mode systems, - 11 that frequency bands which could be used in automatic determination of location and guidance (ADLG) i
25、n the land mobile services would be found within the bands allocated to radiolocation and mobile as necessary for specific uses described in Annexes 1 and 2. a brief description of each is given at Annex 2; - STDmITU-R RECMN M.1307-ENGL 1997 lI855212 05315bb 237 Rec. ITU-R M.1307 167 ANNEX 1 ADL tec
26、hniques The following ADL techniques can be used individually or in combination to meet the operational requirements of land mobile users: 1 Multilater ation 1.1 Hyperbolic Location is determined using distance differences from three or more fixed transmitting sites. These differences can either be
27、expressed by phase differences between received signals (phase multilateration) or differences in the time of arrivai of leading edges of synchronized pulse signals (pulse multilateration) producing hyperbolic lines of constant phase or time differences. Location is then determined from the intersec
28、tion of these lines. 2 Non-multilateration 2.1 Proximity A number of techniques may be employed which use proximity detection: 2.1.1 Tag readers Location is determined by proximity to signposts of precisely known location. A wide range of techniques has been employed to this end (generally for locat
29、ion of vehicles), including inductive loops, UHF radio transmission, microwave transmission and infrared transmissions. Generally, signposts at known locations along a predetermined route are equipped with small low power transmitters. The vehicles travelling the route are equipped with “tags” affix
30、ed to their sides which, at close range, passively reflect or retransmit the signal from the signpost - modulating the signal to provide specific information about the vehicle - which the signpost receives in acknowledgment to its interrogation. This information is then relayed to the dispatcher. Th
31、is type of system may also be useful for tracking objects in manufacturing assembly lines for quality control, and in electronic toll and traffic management systems. 2.1.2 Homing devices Radio-frequency beacons have been successfully used for the purpose of locating stolen vehicles. A transmitter is
32、 automatically activated upon unauthorized use of the vehicle. The location of the vehicle is then determined using direction finding arrays and triangulation. 2.1.3 Radar proximity devices Super high frequency short range radar can be used in vehicles to detect the presence of other vehicles moving
33、 into range for potential collision. These form the basis of land mobile collision avoidance systems. 2.1.4 Dead reckoning These techniques employ heading and distance-travelled sensors for calculating the location of vehicles relative to fixed known location references. Location determination accur
34、acies depend on the sensing devices, frequency of reference updates and the severity of external factors such as magnetic field variation, wheel slippage and road camber, etc. 2.1.5 Links Links are used in multilateration systems, as follows. 2.1.5.1 Forward links A forward link is any signal transm
35、itted to a mobile unit to be located by a multilateration system. STD-ITU-R RECMN MmL307-ENGL 1777 M q85-5212 0533567 173 168 Rec. ITU-R M.1307 2.1.5.2 Reverse links A reverse link is a multilateration signal transmitted to the fixed or base station. Reverse link signals are contained within the bro
36、adband segment of the multilateration signal and are primarily location pulses originating from mobile units and used for determination of the position of mobile units. Such transmissions may also originate from other fixed or base stations for the purpose of system synchronization or testing. These
37、 transmissions are likely to occur less frequently and more randomly than forward links and are therefore less likely to cause interference. 2.1.5.3 Communication links Communication links emanate from the fixed or base station and mobile units ancillary to the ADL function of the multilateration sy
38、stem, and provide status and instructional information relating to the vehicle being located or its occupants. These links may be interconnected with the PSTN to enable emergency communications. 3 Satellite Satellites in the mobile-satellite service may be used to relay information concerning the lo
39、cation of vehicles. Satellite systems may be similarly employed in search and rescue operations. The vehicle or person in distress activates an emergency transmitter which relays its location to a rescue centre. ANNEX 2 Guidance systems 1 Autonomous systems Autonomous systems do not require any exte
40、rnal map data or route guidance calculation. There are three types of autonomous systems - directional aids, map display, and route guidance systems. 1.1 Directional aids These systems primarily use dead reckoning techniques, although some include other methods such as GPS. An on- board processor es
41、timates the vector connecting the initial location with the destination. The route of travel is inferred by the driver using the heading and distance information provided. 1.2 Map display systems These systems indicate position on a map display of digitized cartographic data. The vehicle tracks its
42、own progress along the route using gyroscopes, map matching, dead reckoning, and GPS techniques. Centrally assembled digital traffic information can be transmitted to the vehicle and displayed on the map for the drivers information. 1.3 Route guidance systems These systems include an on-board comput
43、er, which computes turn-by-turn driving directions. The vehicle tracks its own progress using gyroscopes, map matching, dead reckoning, and GPS techniques, and corrects the routing instructions as necessary. These systems may also accept digital traffic information for real-time route optimization.
44、2 Infrastructure supported systems In infrastructure supported systems, a large number of roadside signposts are installed at strategic locations. Guidance between signposts is accomplished by dead reckoning techniques. A vehicle on-board computer measures journey time between signposts and transmit
45、s this information to a central controller via two-way communication signposts which STD-ITU-R RECMN M-L307-ENGL 3997 4855232 O533568 OOT Rec. ITU-R M.1307 169 have combined active and passive functions. Journey time, together with the traffic conditions, is taken into account by a central computer
46、which determines the best route for each individual user. The recommended route information is then transmitted back to the user through the signpost network. Guidance and current traffic information are available in this system, but the information is only valid within the coverage area of the infr
47、astructure network. 3 Dual mode systems Dual mode systems combine features of infrastructure-based and autonomous route guidance systems. In city centres and other densely populated and congested areas, infrastructure-based mode is used to combine route guidance capabilities with real-time traffic m
48、anagement. Signalized intersections or other appropriate structures in the central area are equipped with beacons. Outside the central area, the system switches to autonomous mode, providing wide area route guidance capabilities without need for infrastructure. APPENDIX 1 ADLG system used in the Uni
49、ted States of America The band 902-928 MHz is one band that will be used for ADLG in the United States. The basic technical and operational characteristics of this system are as follows: 1 Technical parameters 1.1 Bandwidth The bandwidth used will vary depending upon the type of ADL system or utilization, as follows: - - - Maximum peak effective radiated power (e.r.p.) is limited to 300 W for narrow-band datalinks and 30 W for multilateration and non-multilateration systems, in order to reduce the potential for interference between ADL systems and between
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