1、TIA/EIA INTERIM STANDARD A Position Determination Standard for Analog Systems Addendum 1 TIA/EIA/IS-817-1 (Addendum No. 1 to TIA/EIA/IS-8 7) FEBRUARY 2002 TELECOMMUNICATIONS INDUSTRY ASSOCIATION The Teleconmunications Industry Association represents the conmunications sector of NOTICE TIA/EIA Engine
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10、n approved by the Telecommunications Industry Association. Distribution of this TIA/EIA Interim Standard for comment shall not continue beyond 36 months fom the date of publication. It is expected that following this 36 month period, this TIA/EIA Interim Standard, revised as necessary, will be submi
11、tted to the American National Standards Institute for approval as an American National Standard. Suggestions for revision should be directed to: Standards Minimize message size to keep the mute time to a minimum; Provide messages that support both autonomous and wireless-assisted GPS location servic
12、es . 1.2. Definitions Acquisition Assistance. receiver in acquiring (detecting) signals from the GPS satellites. Almanac. A set of orbit and clock correction parameters for all GPS satellites. It is a subset of the ephemeris data with reduced accuracy, and allows calculation of approximate GPS satel
13、lite positions and clock corrections. Angle of Axis for Position Uncertainty. Position uncertainty is represented as a 1-0 (one standard deviation) ellipse. This angle is the angle of one of the ellipses axes with respect to True North. Information about the GPS system/signals that aids the GPS Assi
14、stance Data. various purposes (e.g., acquisition, location calculation or sensitivity improvement). Autonomous Mobile Station. A mobile station that is capable of detecting a navigation signal without any assistance. The mobile station may be capable of autonomously calculating its own position. Azi
15、muth. An angle that specifies a direction in the horizontal plane, expressed in degrees measured clockwise from True North. Base Station. his term refers to a number of functions performed on the land side, which are typically distributed between a Base Station Transceiver (BTS), a Base Station Cont
16、roller (BSC), a Mobile Switching Center (MSC) and any Inter-Working Function WF) The assistance data provided by the PDE to the mobile station for 1 TIA/EIA/IS-8 17.1 1 2 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 required for network connection. DE) be
17、low. Chip. The interval defied by the chipping (spreading) rate of the GPS C/A code (1023 kHz). Stated as a time interval, one chip equals approximately 977.5 ns; as a distance it is approximately 293.0 m. In this document, the exact value depends on the instantaneous Doppler shift experienced by th
18、e satellite signal. Code Chip. See Chip. Code Period. One repetition of a periodic digital code. It is used in this document to refer to a repetition ofthe PNcode used by a GPS satellite, which is 1023 chips long. Code Phase. The number (not necessarily integer) of code chips that have elapsed since
19、 the beginning of a code repetition. Doppler nth Order. The nth order moment specifying a satellites observed Doppler. ECEF. “Earth-Centered-Earth-Fixed”. A Kame of reference for specifying positions that is centered in the center of the Earth and rotates with it. Elevation Angle. The angle between
20、a (GPS) satellite and the horizon, expressed in degrees. Ephemeris. The predictions of current satellite positions transmitted by the GPS satellites (among other information) in the Navigation Message Bits. Fix. The process of performing position determination. FOCC Forward Control Channel. See also
21、 the definition of Position Determination Entity Forward Control Channel (Fi.occ). A control channel used from a base station to a mobile stat ion. Forward Link. The communication path Kom the PDE to the mobile station. Forward Voice Channel (FVC). stat ion. FVC Forward Voice Channel. A voice channe
22、l used from a base station to a mobile Geolocation. The process of determining a geographic location. GPS. Global Positioning System. A DOD conceived, implemented and operated constellation of 24 satellites orbiting the Earth at a nominal altitude of about 11,000 miles. The satellites transmit a set
23、 of radio signals expressly structured to enable a suitably-designed receiver to determine its own position. IwF= Interworking Function. A network entity enabling interactions between network elements, such as interactions between an MSC and a landline function. The IWF usually performs protocol con
24、versions as its primary function. Location. The terms “location” and “position” are used interchangeably throughout this document. In this respect, the definition of the term differs Kom the historic use of location in wireless systems to identify the mobiles current serving system. See Position. 2
25、TIA/EIA/IS-8 17.1 1 2 3 4 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 Location Assistance. Information about the GPS system/signals that enables the mobile to compute its own location based on the GPS measurements. LSB. Least Significant Bit. Mobile Station. A s
26、tation that communicates with the base station. Mobile Switching Center (MSC). A configuration of equipment that provides cellular radio-telephone service. Also called the Mobile Telephone Switching Office (MSO). ms. Millisecond second). MSB. Most Significant Bit. MSC. See Mobile Switching Center. N
27、avigation Bits Assistance. receivers ability to detect the GPS signal. It is also useful for time synchronization. Navigation Message Bits. satellites, containing the satellite clock, ephemeris, almanac and other parameters. ns. Nanosecond second). PDE. See Position Determination Entity. Position. T
28、he geographic position of the mobile station expressed in latitude and longitude. Position Determination Entity (PDE). A network entity which manages the position or geographic location determination of the mobile station. Also see Informative Reference 4. Pseudorange. The measured range (in GPS chi
29、p) from the observed satellite to the GPS receiver antenna. Since the satellite and receiver clock biases are included, it is referred to as pseudorange. Reference Bit Boundary. A boundary between two 20-ms GPS bit intervals chosen as the reference point for code phases. RECC. Reverse Control Channe
30、l Information about the GPS signals that improves the GPS The message bits (50 bits per second) transmitted by GPS Reverse Control Channel (RECC). The control channel used from a mobile station to a base station. Reverse Link. The communication path from the mobile station to the PDE. Reverse Voice
31、Channel (RVC). The voice channel used from a mobile station to a base stat ion. RVC. Reverse Voice Channel. Sensitivity. the determination of the geolocation of the mobile station. Sub-Almanac. GPS almanac containing only the orbit and clock parameters for one satellite. SV. Satellite vehicle or sat
32、ellite. The minimum level (dBm) of received GPS signal at mobile station that allows 36 3 TIAIEIAIIS-8 17.1 1 2 3 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 True North. The direction of the geographical North Pole, according to WGS-84, as opposed to Magnetic North, whic
33、h is the direction of the North Magnetic Pole. WGS-84. World Geodetic System - 1984. See Informative Reference 3. WGS-84 Reference Ellipsoid. Worldwide datum reference system defining the surface of the Earth (note: supersedes WGS-72), i.e., the standard physical model of the Earth used for GPS appl
34、ications. Ellipsoid reference models are location specific and may be obtained from Defense MappingAgency publication DMATR 8350.2 (September 30, 1987). 1.3. References 1 -3.1. Normative The following document contains information that is required for implementation of this standard. 1. TIAIEIA-553-
35、4 Mobile Station -Base Station Compatibility Standard, November 1999. 1.3.2. Informative The following documents contain information that may be useful for the understanding andlor implementation of this standard. 1. TIAIEIAIIS-80 1, Position Bterrnination Service Standard for Dual-Mode Spread Spect
36、rum Systems, October 1999 2. ICD-GPS-200C, Navstar GPS Space Segment/Navigation User Interfaces, September 1997. 3. DMATR 8350.2, Bfense MppingAgenq Publication, September 30, 1987. 4. J-STD-036, Enhanced Wireless 9-1-1, Phase II (currently PN-3890). 5. FCC docket 94-102 (including orders 96-264, 99
37、-96 and 99-245). 6. TSB-100, Wireless Network Reference Model, July 1998. 7. TSB-70-4 Mobile Station - Land Station Compatibility Specijication Common Message Protocol Cross-Reference, September 1999. 1.4. Logical Information “Blocks” To ciar the structure of this standard, six logical “blocks” of i
38、nformation are outlined in Table 1.4-1. The Fist three “blocks” represent information conveyed from the PDE to the mobile station. Their purpose is to provide assistance for the mobile-station GPS receiver. The next two “blocks” represent information conveyed from the mobile station to the PDE. Thei
39、r purpose is to convey to the network the result of the GPS measurement performed by the mobile-station GPS receiver. The last “block” is used for the coarse location technique. The term “block” of information is used to convey the idea of a set of information elements that can be viewed as a logica
40、l single unit needed for a particular fiinction regardless of how it is broken up into one or more messages for the purpose of transmission. 4 TIA/EIA/IS-8 17.1 1 2 3 4 5 6 7 8 9 10 11 12 Table 1.4-1. Types of information ?blocks? exchanged between PDE and mobile Direction PDE to Mobile Station Mobi
41、le Station to PDE Information Blocks I. Acquisition Assist ance II. Location Assist ance III. Navigation Bits Assist ance VICalculated Coarse Position Report - Re que s t IV. GPS Measurement Report V. Calculated Position Report VL Calculated Coarse Position Report Description Information about the G
42、PS system/ signals that aids the GPS receiver in acquiring (detecting) signals from the GPS satellites. Information about the GPS system/ signals that enables the mobile to compute its own location based on the GPS measurements. Information about the 50-bps bit streams modulated onto the GPS satelli
43、te signals. Information about the GPS system/ mobile station approximate location that aids the GPS receiver in acquiring signals from the GPS satellites, and enables the mobile to compute its own coarse location based on the GPS measurements. Observed parameters of the GPS signals (e.g., code phase
44、s). These parameters are needed to compute mobile position. The geographical position data for the mobile station (latitude, longitude, etc.) A mobile station that is capable of computing its position uses this block to report the results. Amobile station that is capable of computing its coarse posi
45、tion uses this block to report the results. This document distinguishes between the base station (BS) and the PDE. The BS transmits to and receives from the mobile station. The PDE supports the position determination process, formulates all the information to be transmitted by the base station, and
46、processes all the data returned by the mobile station. The interconnection between PDE and BS is beyond the scope of this document. To perform an assisted GPS geolocation, the PDE sends an information block of type 1 to the mobile station. In response, the mobile may ask for additional assistance bl
47、ocks of type 2 and/ or 3, as needed. Then, the mobile station performs a measurement of the GPS satellite signals and reports the result to the PDE with a block of type 4 or 5. To perform an unassisted GPS geolocation, the PDE simply sends a request for a block of type 5. To 5 TIA/EIA/IS-8 17.1 5 6
48、7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 perform coarse location, the PDE broadcasts current GPS sub-almanacs and sends a request for a block of type 6. Then the mobile station performs a measurement of the GPS satellite signals, and it reports the calculated coarse po
49、sition to the PDE with a block of type 6. For transmission over the air, each PDE-to-mobile information block is subdivided into one or more messages. More specifically, PDE-to-mobile blocks 1, 2 and 3 are subdivided into GPS Assistance messages, each of which is individually acknowledged through a GPS Assistance - Response message. The details of how this subdivision is performed are summarized in the sections that follow. Mobile-to-PDE blocks 4 and 5 are embedded in a GPS Report message to be sent in response to GPS Report - Request message issued by the PDE. PDE-to-Mobile bloc
