A.3 Measure Position Response

3GPP44.031Location Services (LCS)Mobile Station (MS) - Serving Mobile Location Centre (SMLC) Radio Resource LCS Protocol (RRLP)Release 17TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

A.3.1 General

The Measure Position Response is a RRLP component from the MS to the network. It is the response to the Measure Position Request. It contains the following elements. One of the five elements containing measurement data or location estimate (E-OTD Measurement Information, Location Information, GPS Measurement Information, GANSS Measurement Information or GANSS Location Information) or Location Information Error element must be included.

Table A.2: Measure Position Response component content

Element	Type/Reference	Presence
Multiple Sets	Multiple Sets 3.2.1	O
Reference BTS Identity	Reference BTS Identity 3.2.2	O
E-OTD Measurement Information	E-OTD Measurement Information 3.2.3	O
Location Information	Location Information 3.2.4	O
GPS Measurement Information	GPS Measurement Information 3.2.5	O
Location Information Error	Location Information Error 3.2.6	C
GPS Time Assistance Measurements	GPS Time Assistance Measurements 3.2.6a	O
Velocity Estimate	Velocity Estimate 3.2.6b	O
Extended Reference	Extended Reference 3.2.7	C
Uplink RRLP Pseudo Segmentation Indication	Uplink RRLP Pseudo Segmentation Indication 3.2.8	C
GANSS Location Information	GANSS Location Information 3.2.9	O
GANSS Measurement Information	GANSS Measurement Information 3.2.10	O

A.3.2 Elements

A.3.2.1 Multiple Sets Element

This element indicates how many E-OTD Measurement Information sets, GPS Measurement Information sets or GANSS Measurement Information sets, and Reference BTS Identities are included to this element. This element is optional. If this element is absent, a single measurement set is included.

Number of E-OTD/GPS/GANSS Measurement Information Sets

This field indicates the number of Number of E-OTD/GPS/GANSS Measurement Information sets included to this component. This field is mandatory. If two or more types of measurement elements are present, then there are the equal number of them, and each pair has the same reference BTS.

Range: 2 – 3

Number of Reference BTS

This field indicates the number of reference BTSs used in this component. This field is mandatory.

Range: 1-3

Reference BTS relation to Measurement Elements

This field indicates how the reference BTSs listed in this element relate to measurement sets later in this component. This field is conditional and included only if Number of E-OTD/GPS/GANSS Measurement Information Sets is ‘3’ and Number of Reference BTSs is ‘2’.

‘0’ = First reference BTS is related to first and second E-OTD/GPS/GANSS Measurement Information Sets, and second reference BTS is related to third E-OTD/GPS Measurement Information Sets.

‘1’ = First reference BTS is related to first and third E-OTD/GPS/GANSS Measurement Information Sets, and second reference BTS is related to second E-OTD/GPS/GANSS Measurement Information Sets.

‘2’ = First reference BTS is related to first E-OTD/GPS/GANSS Measurement Information Sets, and second reference BTS is related to second and third E-OTD/GPS/GANSS Measurement Information Sets.

If this field is not included, the relation between reference BTS and Number of E-OTD/GPS/GANSS Measurement Information Sets is as follows:

– if there are three sets and three reference BTSs -> First reference BTS relates to first set, second reference BTS relates to second set, and third reference BTS relates to third set;

– if there are two sets and two reference BTS -> First reference BTS relates to first set, and second reference BTS relates to second set;

– if there is only one reference BTS and 1-3 sets -> this reference BTS relates to all sets.

A.3.2.2 Reference BTS Identity Element

This element identifies the reference BTS(s). This element is conditional to the number of reference BTSs. It is mandatory, if there is more than one reference BTS, and optional otherwise. If this element is not included, the Reference BTS, used in other elements, is the current serving BTS of MS. If this element is included, the BTSs defined here are used as Reference BTSs in all other elements.

The following fields are repeated for the number of reference BTSs included in the Number of Reference BTS field.

CellIdType

This field indicates is the identity method of the Reference BTS. This field is mandatory within this element.

‘0’ = Cell identity is told using BSIC and BCCH carrier.

‘1’ = Cell identity is told using CI, and the LAC is the same as the current serving BTS.

‘2’ = Cell identity is told using an index referring to the BTS listed in the Measure Position Request component (the indicated reference BTS is 1)

‘3’ = Cell identity is told using an index referring to the BTS listed in the BCCH allocation list (System Information Neighbor Lists) of the serving BTS. This type of reference identity shall not be used by the MS unless it has received the "E-OTD Measurement Assistance Data for System Information List Element" from the SMLC for this cell.

‘4’ = Cell identity is told using CI, and the LAC.

Reference LAC

This field indicates the Location Area Code of the reference BTS. The purpose of the Location Area Code is to identify a location area. This field is conditional, and included, if CellIDType field is ‘4’.

Range: 0 – 65535

Reference CI

This field indicates the Cell Identity value of the reference BTS. The purpose of the Cell Identity value is to identify a cell within a location area. This field is conditional, and included, if CellIDType field is ‘1’ or ‘4’.

Range: 0 – 65535

Reference BCCH Carrier

This field indicates the absolute RF channel number of the BCCH of the reference base station. BCCH carrier field is conditional and is included only if CellIdType is set ‘0’.

Range: 0 – 1023

Reference BSIC

This field indicates the BSIC (Base Station Identity Code of the base station).

BSIC field is conditional and is included only if CellIdType is set ‘0’ or ‘3’.

Range: 0 – 63

Request Index

This field indicates an index identifying the reference BTS by referring to the BTSs listed in the Measure Position Request component (the indicated reference BTS in the Measure Position Request component has the index value 1, and possible next BTS ‘2’, and so on )

This field is conditional and included only if CellIdType is set to ‘2’.

Range: 1-16

System Info Index

This field indicates an index identifying the reference BTS by referring to the BCCH allocation list (System Information Neighbor List) of the serving BTS .

This field is conditional and included only if CellIdType is set to ‘3’.

Range: 1-32

A.3.2.3 E-OTD Measurement Information Element

The purpose of the E-OTD Measurement Information element is to provide OTD measurements of signals sent from the reference and neighbor based stations. The length of this element depends on the number of neighbor cells for which OTD measurements have been collected. This element is optional in the Measure Position Response component. It is included in the Measure Position Response component, if the network has requested the mobile to perform the MS assisted E-OTD method. BTSs which cannot be measured or whose measurements are excessively inaccurate need not be reported. The MS may include measurements for other BTSs not given in the assistance data by the SMLC.

The E-OTD and 51 multiframe offset values are reported relative to the reference BTS as defined in the previous sub-clauses.

The following fields are repeated for each measurement set.

Reference Frame Number

This field indicates the frame number of the last measured burst from the reference BTS modulo 42432. This information can be used as a time stamp for the measurements. This field is mandatory.

Range: 0 – 42431

Reference Time Slot

Reference Time Slot indicates the time slot modulo 4 relative to which the MS reports the reference BTS measurements. This field is mandatory.

Range: 0 to 3

NOTE 1: If MS does not know timeslot scheme, the MS reports the used timeslot. MS can only report results based on one time slot (N) or two time slots (N and N+4). If the MS knows the timeslot scheme, it can make measurements from several timeslots and reports that the used timeslot is zero (and makes correction).

Reference Quality

Reference Quality field includes the standard deviation of the TOA measurements from the reference BTS with respect to T_Ref (where T_Ref is the time of arrival of signal from the reference BTS used to calculate the OTD values). This field is optional. The Reference Quality field can be used to evaluate the reliability of E-OTD measurements in the SMLC and in weighting of the E-OTD values in the location calculation.

Following linear 5 bit encoding is used:

‘00000’ 0 – (R*1-1) meters;

‘00001’ R*1 – (R*2-1) meters;

‘00010’ R*2 – (R*3-1) meters;

…

‘11111’ R*31 meters or more.

where R is the resolution defined by Std Resolution field. For example, if R=20 meters, corresponding values are 0 – 19 meters, 20 – 39 meters, 40 – 59 meters, …, 620+ meters.

Number of Measurements

Number of Measurements for the Reference Quality field is used together with Reference Quality to define quality of the reference base site TOA. The field indicates how many measurements have been used in the MS to define the standard deviation of the measurements. Following 3 bit encoding is used:

‘000’: 2-4;

‘001’: 5-9;

‘010’: 10-14;

‘011’: 15-24;

‘100’: 25-34;

‘101’: 35-44;

‘110’: 45-54;

‘111’: 55 or more.

This field is optional.

Std Resolution

Std Resolution field includes the resolution used in Reference Quality field and Std of EOTD Measurements field. Encoding on 2 bits as follows:

’00’ 10 meters;

’01’ 20 meters;

’10’ 30 meters;

’11’ Reserved.

This field is mandatory.

TA Correction

This field indicates the estimate of the time difference between the moment that the MS uses to adjust its internal timing for reception and transmission (e.g. corresponding to maximum energy) and the estimate of the reception of the first arriving component from the serving BTS. This value can be used as a correction by the SMLC to the Timing Advance (TA) value when the distance between the MS and the serving BTS is estimated based on TA.

The value TACor in this field corresponds to the TA Correction in bit periods as follows:

– TA Correction in bit periods = TACor/64 -8.

TA Correction has the resolution of 1/64 bit period, and the range – 8 … +7 bit periods. Negative TA Correction in bits indicates that the first signal component from the serving BTS is estimated to arrive before the moment used for communication. This field is optional.

Range: 0-960

Number of Measured Neighbors

This field indicates the number of different neighbor BTSs. This field is mandatory.

Range: 0 – 10

NOTE 2: If the MS can not measure any neighbor BTSs, then this value is set to ‘0’.

The following fields are repeated for the number of BTSs included in the Number of Measured Neighbors field.

Neighbor Identity Present

The presence of this field is conditional, it shall not be present in the first set. It is mandatory for the other sets. This field indicates whether the identity information (i.e. CellIDType and possibly Neighbor CI / Neighbor BCCH Carrier / Neighbor BSIC / Neighbor Multiframe Offset / Request Index / System Info Index fields) concerning a certain BTS is present or whether the BTS identity is given as reference to the first measurement set.

‘0’ Identity information not included, and identity of this BTS is same as the identity of BTS in first set with same sequence number.

‘1’ Identity information is included.

CellIdType

This field indicates is the identity method of the cell. This field is conditional, and included if Neighbor Identity Present is ‘1’. If CellIdType field is not present, the following fields can not be present either: Neighbor CI, Neighbor BCCH Carrier, Neighbor BSIC, Neighbor Multiframe Offset, Request Index, System Info Index.

‘0’ = Cell identity is told using BSIC and BCCH carrier.

‘1’ = Cell identity is told using CI, and the LAC is the same as the current serving BTS.

‘2’ = Cell identity is told using 51 Multiframe offset and BCCH carrier.

‘3’ = Cell identity is told using an index referring to the BTS listed in the Measure Position Request component (the indicated reference BTS is 1).

‘4’ = Cell identity is told using an index referring to the BTS listed in the BCCH allocation list (System Information Neighbor Lists) of the serving BTS. This type of neighbor identity shall not be used by the MS unless it has received the "E-OTD Measurement Assistance Data for System Information List Element" from the SMLC for this cell.

‘5’ = Cell identity is told using CI and the LAC.

NOTE: The MS can decide which of these methods to use. The CellIdType ‘3’ and ‘4’ are preferred.

Neighbor LAC

This field indicates the Location Area Code of the neighbor BTS. The purpose of the Location Area Code is to identify a location area. This field is conditional, and included, if CellIDType field is ‘5’.

Range: 0 – 65535

Neighbor CI

This field indicates the Cell Identity of the particular neighbor cell. The purpose of the Cell Identity value is to identify a cell within a location area.

Neighbor CI field is conditional and is included only if CellIdType is set ‘1’ or ‘5’ and the CI value of the given cell is available.

Range: 0 – 65535

Neighbor BCCH Carrier

This field indicates the absolute RF channel number of the BCCH of the neighbor base station. BCCH carrier field is conditional and is included only if CellIdType is set ‘0’ or ‘2’.

Range: 0 – 1023

Neighbor BSIC

This field indicates the BSIC (Base Station Identity Code of the base station).

BSIC field is conditional and is included only if CellIdType is set ‘0’ or ‘4’.

Range: 0 – 63

Neighbor Multiframe Offset

This field indicates the frame difference between the start of the 51 multiframes frames arriving from this BTS and the reference BTS. The multiframe offset is defined as T_BTS– T_Ref, where T_BTS is the time of the start of the 51 multiframe in the BTS in question, and T_Ref is the time of the start of the 51 multiframe in the reference BTS. This field is conditional and included only if CellIdType is set to ‘2’.

Range: 0 – 51

Request Index

This field is conditional and included only if CellIdType is set to ‘3’.

Range: 1-16

System Info Index

This field indicates an index identifying the reference BTS by referring to the BCCH allocation list (System Information Neighbor List) of the serving BTS.

This field is conditional and included only if CellIdType is set to ‘4’.

Range: 1-32

Neighbor Time Slot

Neighbor Time Slot indicates the time slot modulo 4 relative to which the MS reports the neighbor BTS measurements. This field is mandatory.

Range: 0 to 3

NOTE 3: If the MS does not know the timeslot scheme, the MS reports the used timeslot. MS can only report a result based on one time slot (N) or two time slots (N and N+4). If the MS knows the timeslot scheme, the MS can make measurements from several timeslots and reports that the used timeslot is zero (and makes correction).

Number of EOTD Measurements

Number of Measurements field is used together with Std of EOTD Measurements field to define quality of a reported EOTD measurement. The field indicates how many EOTD measurements have been used in the MS to define the standard deviation of these measurements. Following 3 bit encoding is used.

‘000’: 2-4;

‘001’: 5-9;

‘010’: 10-14;

‘011’: 15-24;

‘100’: 25-34;

‘101’: 35-44;

‘110’: 45-54;

‘111’: 55 or more.

This field is mandatory.

Std of EOTD Measurements

Std of EOTD Measurements field includes standard deviation of EOTD measurements. This field is mandatory. It can be used to evaluate the reliability of EOTD measurements in the SMLC and in weighting of the OTD values in location calculation.

Following linear 5 bit encoding is used:

‘00000’ 0 – (R*1-1) meters;

‘00001’ R*1 – (R*2-1) meters;

‘00010’ R*2 – (R*3-1) meters;

…

‘11111’ R*31 meters or more.

where R is the resolution defined by Std Resolution field. For example, if R=20 meters, corresponding values are 0 – 19 meters, 20 – 39 meters, 40 – 59 meters, …, 620+ meters.

OTD

This field indicates the measured OTD value between the receptions of signals from the reference and the neighbor BTS. The OTD is defined as T_Nbor– T_Ref (modulo burst length) where T_Nbor is the time of arrival of signal from the neighbor BTS, and T_Ref is the time of arrival of signal from the reference BTS. The reporting resolution of the OTD value is 1/256 bit. This field is mandatory.

Range: 0 – 39999

A.3.2.3a E-OTD Measurement Extended Information Element

The purpose of the E-OTD Measurement Ext Information element is to provide OTD measurements of signals sent from the reference and neighbour base stations. The length of this element depends on the number of neighbour cells for which OTD measurements have been collected. This element is optional in the Measure Position Response component. It is included in the Measure Position Response component, if E-OTD measurements didn’t fit in the E-OTD Measurement Information Element.

The E-OTD and 51 multiframe offset values are reported relative to the reference BTS as defined in the previous sub-clauses.

The following fields are valid only for the first set of measurements

Number of Measured Neighbors

This field indicates the number of different neighbor BTSs. This field is mandatory.

Range: 0 – 5

NOTE: If the MS can not measure any neighbor BTSs, then this value is set to ‘0’.

The following fields are repeated for the number of BTSs included in the Number of Measured Neighbors field. They are defined in the previous sub-clause :

– CellIdType,

– Neighbor LAC,

– Neighbor CI,

– Neighbor BCCH Carrier,

– Neighbor BSIC,

– Neighbor Multiframe Offset,

– Request Index,

– System Info Index,

– Neighbor Time Slot,

– Number of EOTD Measurements,

– Std of EOTD Measurements,

– OTD

A.3.2.4 Location Information Element

The purpose of Location Information element is to provide the location estimate from the MS to the network, if the MS is capable of determining its own position. Optionally, the element may contain the velocity parameters computed by the MS.

This element is optional. This element contains the following fields.

Reference Frame

This field specifies the reference BTS Reference Frame number during which the location estimate was measured. The time of the Reference Frame boundary is as observed by the MS, ie without Timing Advance compensation. This field is mandatory. However, if the Reference Frame number is within (42432..65535), the value of this field shall be ignored and in that case the MS should provide GPS TOW if available.

Table A.3: Reference Frame field contents

Parameter	# of Bits	Resolution	Range	Units
Reference Frame	16	—	0 – 65535	frames

Note that expected values for Reference Frame are in range 0 – 42431.

GPS TOW

This field specifies the GPS TOW for which the location estimate is valid , rounded down to the nearest millisecond unit. This field is optional but shall be included if GPS Time Assistance Measurements are included. If GPS Time Assistance Measurements are included in the RRLP Measure Position Response, the MS shall align GPS System time (as defined by the GPS TOW and the GPS TOW Subms fields) with the reported GSM frame boundary observed by the MS at that time.

Table A.4: GPS TOW field contents

Parameter	# of Bits	Resolution	Range	Units
GPS TOW	24	1 ms	0 – 14399999	ms

The 24 bits of GPS TOW are the least significant bits. The most significant bits shall be derived by the Serving Mobile Location Center to unambiguously derive the GPS TOW.

Fix Type

This field contains an indication as to the type of measurements performed by the MS: 2D or 3D. This field is mandatory.

‘0’ = 2D fix.

‘1’ = 3D fix.

Position Estimate

This field contains the calculated position estimate in the format defined in 3GPP TS 23.032. The allowed shapes are:

– ellipsoid Point;

– ellipsoid point with uncertainty circle;

– ellipsoid point with uncertainty ellipse;

– ellipsoid point with altitude and uncertainty ellipsoid.

A.3.2.5 GPS Measurement Information Element

The purpose of the GPS Measurement Information element is to provide GPS measurement information from the MS to the SMLC. This information includes the measurements of code phase and Doppler, which enables the network-based GPS method where position is computed in the SMLC. The proposed contents are shown in table A.5, and the individual fields are described subsequently. See also Figure A.1 for an illustration of the relation between some of the fields.

Figure A.1. Exemplary definitions of GPS measurement information fields.

This element is included in the Measure Position Response component if the network has requested the mobile to perform mobile-assisted location measurements using a GPS location method.

Following fields are repeated a number of times told in Number of E-OTD/GPS Measurement Sets field if Multiple Sets element is included. If Multiple Sets element is not included, the default value for sets is one (i.e. the following fields are present only once).

Table A.5: GPS Measurement Information element content

Element fields	Presence	Occurrences
Reference Frame	O	1
GPS TOW	M	1
# of Satellites (N_SAT)	M	1
Measurement Parameters	M	N_SAT

The following paragraphs describe the content of each information field of this element.

Reference Frame

This field is optional.

Table A.6: Reference Frame field contents

Parameter	# of Bits	Resolution	Range	Units
Reference Frame	16	—	0 – 65535	frames

Note that expected values for Reference Frame are in range 0 – 42431. If Reference Frame and GPS Time Assistance Measurements both are included in the RRLP Measure Position Response, the code phase measurements shall be aligned with the reported GSM frame boundary observed by the MS at that time, as indicated in Figure A.1. The time of the Reference Frame boundary is as observed by the MS, ie without Timing Advance compensation.

GPS TOW

This field specifies the GPS TOW for which the location estimate is valid, rounded down to the nearest millisecond unit.This field is mandatory.

Table A.7: GPS TOW field contents

Parameter	# of Bits	Resolution	Range	Units
GPS TOW	24	1 ms	0 – 14399999	ms

The 24 bits of GPS TOW are the least significant bits. The most significant bits shall be derived by the Serving Mobile Location Center to unambiguously derive the GPS TOW.

NOTE: The GPS Reference Time Uncertainty, if present, indicates the accuracy of GPSTOW, as described in sub-clause A.3.2.6.a.

# of Satellites (N_SAT)

Number of Measurements

This field specifies the number of measurements for which measurements satellites are provided in the component. This value represents the number of satellites that were measured by the MS. This value of N_SAT determines the length of the payload portion of the component. Typical range for N_SAT is four to a maximum of 12. This field is mandatory and occurs once per set.

Table A.7a: # of Satellites field contents

Parameter	# of Bits	Resolution	Range	Units
N_SAT	4	—	1 – 16	—

Measurement Parameters

This field contains information about the measurements of code phase and Doppler, which enables the network-based method where position is computed in the SMLC. This field is mandatory and occurs N_SAT times per message.

Table A.8: Measurement Parameters field contents

Parameter	# of Bits	Resolution	Range	Units
Satellite ID	6	—	0 – 63	—
C/N_o	6	1	0 – 63	dB-Hz
Doppler	16	0,2	6553,6	Hz
Whole Chips	10	1	0 – 1022	chips
Fractional Chips	11	2^-10	0 – (1-2^-10)	chips
Multipath Indicator	2	see Table A.9	TBD	—
Pseudorange RMS Error	6	3 bit mantissa 3 bit exp	0,5 – 112	m

Satellite ID

This field identifies the particular satellite for which the measurement data is valid. This values 0 – 63 represent satellite PRNs 1 – 64, respectively.

C/N₀

This field contains the estimate of the carrier-to-noise ratio of the received signal from the particular satellite used in the measurement. It is given in whole dBs and has a range of 0 to 63. Typical levels observed by MS-based GPS units will be in the range of 20 dB to 50 dB.

Doppler

This field contains the Doppler measured by the MS for the particular satellite signal. This information can be used to compute the 3-D velocity of the MS. The Doppler range is sufficient to cover the potential range of values measured by the MS.

Whole Chips

This field contains the whole value of the code-phase measurement made by the MS for the particular satellite signal at the time of measurement, in units of 1 GPS chip in the range from 0 to 1022 chips, where increasing binary values of the field signify increasing measured pseudoranges. The code phase measurement is divided into two fields, "Whole Chips" and "Fractional Chips".

Fractional Chips

This field contains the fractional value of the code-phase measurement made by the MS for the particular satellite signal at the time of measurement. The resolution of the fractional portion is approximately 0,3 m.

NOTE: The actual ASN.1 coding of this field reserves 11 bits for legacy compatibility. Only the 10 least significant bits are actually required to code the values (0..1023)

Multipath Indicator

This field contains the Multipath Indicator value. This parameter is specified according to the representation described in table A.9.

Table A.9: Multipath Indicator values and associated indications

Value	Multipath Indication
00	Not measured
01	Low, MP error < 5m
10	Medium, 5m < MP error < 43m
11	High, MP error > 43m

Range: 0 – 3

Pseudorange RMS Error

This field contains a Pseudorange RMS Error value.

Range: 0,5 m to 112 m

NOTE: This parameter is specified according to a floating-point representation as described in Table A.10.

Table A.10: Pseudorange RMS Error representation

Index	Mantissa	Exponent	Floating-Point value, x_i	Pseudorange value, P
0	000	000	0,5	P < 0,5
1	001	000	0,5625	0,5 <= P < 0,5625
I	x	y	0,5 * (1 + x/8) * 2^y	x_i-1 <= P < x_i
62	110	111	112	104 <= P < 112
63	111	111	—	112 <= P

A.3.2.6 Location Information Error Element

The purpose of Location Information Error element is to provide the indication of error and the reason for it, when the MS can not perform the required location or the network can not determine the position estimate. The element may also indicate what further assistance data may be needed by the target MS to produce a successful location estimate or location measurements. This element is optional. This element has the following fields.

Error Reason

This field indicates the reason for error. This field is mandatory.

‘0’: Undefined error.

‘1’: There were not enough BTSs to be received when performing mobile based E-OTD.

‘2’: There were not enough GPS satellites to be received, when performing GPS location.

‘3’: E-OTD location calculation assistance data missing.

‘4’: E-OTD assistance data missing.

‘5’: GPS location calculation assistance data missing.

‘6’: GPS assistance data missing.

‘7’: Requested method not supported.

‘8’: Location request not processed.

‘9’: Reference BTS for GPS is not the serving BTS.

’10’: Reference BTS for E-OTD is not the serving BTS.

’11’: There were not enough GANSS satellites received, when performing GANSS location.

’12’: GANSS assistance data missing.

’13’: Reference BTS for GANSS is not the serving BTS.

Additional Assistance Data

This field is optional. Its presence indicates that the target MS will retain assistance data already sent by the SMLC. The SMLC may send further assistance data for any new location attempt but need not resend previous assistance data. The field may contain the following:

GPS Assistance Data:	Necessary additional GPS assistance data (structure and encoding as for the GPS Assistance Data IE in 3GPP TS 49.031 excluding the IEI and length octets)
GANSS Assistance Data:	Necessary additional GANSS assistance data (structure and encoding as for the GANSS Assistance Data IE in 3GPP TS 49.031 excluding the IEI and length octets)

A.3.2.6a GPS Time Assistance Measurements Element

This IE contains measurements that are used to define an accurate relation between GSM and GPS time or to provide additional GPS TOW information for MS Assisted A-GPS. The contents are shown in Table A.10a, and the individual fields are described subsequently.

Table A.10a: GPS Time Assistance Measurements Information element content

Element fields	Presence
Reference Frame MSB	O
GPS TOW Subms	O
Delta TOW	O
GPS Reference Time Uncertainty	O

Reference Frame MSB

This field shall be included when GPS-GSM time association is provided for either MS Based A-GPS or MS Assisted A-GPS. It indicates the Most Significant Bits (MSBs) of the frame number of the reference BTS corresponding to the GPS measurement or location estimate. Starting from the complete GSM frame number denoted FN, the MS calculates Reference Frame MSB as

Reference Frame MSB = floor(FN/42432)

The complete GSM frame number FN can then be reconstructed in the SMLC by combining the fields Reference Frame with Reference Frame MSB in the following way

FN = Reference Frame MSB*42432+Reference Frame

Range: 0-63

GPS TOW Subms

This field is only applicable for MS-Based A-GPS. This field indicates in units of 100ns the submillisecond part of the GPS time of measurement. This field together with the GPS TOW field in the Location Information Element provides a more accurate time stamp of the location estimate for MS based AGPS Expressed in units of microseconds. The precise GPS time of measurements in milliseconds is thus equal to

GPS TOW + 0,0001*GPS TOW Subms

The estimation of precise GPS time of measurement using AGPS is vulnerable to millisecond ambiguities. Therefore the MS shall only report this field when it is confident that any millisecond ambiguities have been avoided.

Range: 0-9999

Delta TOW

This field is only applicable for MS-Assisted A-GPS. This field specifies the difference in milliseconds between the GPS TOW reported in the GPS Measurement Information Element and the millisecond part of the SV time tsv_1 of the first SV in the list reported from the MS. Figure A.1 shows an example of Delta TOW calculation. The Delta TOW is defined as Delta TOW = GPS TOW – fix(tsv_1)

where fix() denotes rounding to the nearest integer towards zero. The estimation of tsv_1 which forms the basis for the calculation of Delta TOW is vulnerable to millisecond ambiguities. Therefore the MS shall only report this field when it is confident that the correct millisecond event has been recovered.

Range: 0-127

GPS Reference Time Uncertainty

This element is optional. It provides the accuracy of the relation GPS and GSM time in the Location Information or GPS Measurement Information Element when GPS-GSM time association is provided. For MS Assisted A-GPS when GPS-GSM time association is not provided, even if GPS Time Assistance Measurement Request is not included in the Measure Position Request, this element can be included to provide the accuracy of the reported GPS TOW. The interval, range and treatment is as described in sub-clause 2.2.4b.

A.3.2.6b Velocity Estimate Element

This field contains the calculated velocity estimate in the format defined in 3GPP TS 23.032. The allowed encodings are:

– Horizontal Velocity

– Horizontal with Vertical Velocity

– Horizontal Velocity with uncertainty

– Horizontal with Vertical Velocity and uncertainty

A.3.2.7 Extended Reference IE

This IE shall be included in any Measure Position Response if and only if an Extended Reference IE was received in the corresponding previous Measure Position Request message.

NOTE: For reasons of backward compatibility, a Release 4 or earlier MS will not include this IE.

The Extended Reference IE contains the following elements.

SMLC code: an integer in the range 0-63. The value returned by a target MS in a Measure Position Response shall equal the value received from the SMLC in the earlier Measure Position Request.

Transaction ID: an integer in the range 0-262143 distinguishing different RRLP transactions in different MSs currently being served by the same SMLC. The value returned by a target MS in a Measure Position Response shall equal the value received from the SMLC in the earlier Measure Position Request.

When an MS employs pseudo-segmentation to return an RRLP response, the same Extended Reference IE shall be included in each RRLP Measure Position Response component.

A.3.2.8 Uplink RRLP Pseudo Segmentation Indication

This element is included by the MS when up-link RRLP pseudo-segmentation is used. In the first segment, ‘first of many’ is indicated and in the second ‘second of many’ is indicated. It is not included when up-link pseudo-segmentation is not used.

A.3.2.9 GANSS Location Information Element

The purpose of GANSS Location Information element is to provide the GANSS location estimate from the MS to the SMLC, if the MS is capable of determining its own position. Optionally, the element may contain Reference Frame element for including accurate relation between the cellular frame and GANSS Time of Day (TOD) for the serving cell if requested by the SMLC.

If GANSS Positioning Method was included in a Measure Position Request component, this field shall be used to report the location estimate from the MS to the network.

The time reference of GANSS TOD in GANSS Location Information Element can be any GNSS specific system time. The time reference is indicated by GANSS_TIME_ID.

The contents of GANSS Location Information are shown in Table A.10.1, and the individual fields are described subsequently.

Table A.10.1: GANSS Location Information Element Content

Element fields	Presence
Reference Frame	O (note 1)
GANSS TOD	O (note 1)
GANSS TOD Frac	O
GANSS TOD Uncertainty	O
GANSS_TIME_ID	O (note 2)
Fix Type	M
Position Data	M
Stationary Indication	O
Location Estimate	M
NOTE 1: Either Reference Frame or GANSS Reference Time shall always be included. NOTE 2. Absence of this field means Galileo

Reference Frame

This element contains Reference FN and Reference FN MSB fields. Reference FN field specifies the reference BTS reference frame number during which the location estimate was measured. The time of the reference frame boundary is as observed by the MS, i.e. without Timing Advance compensation.

Note that expected values for Reference FN are in range 0 – 42431.

Reference FN MSB field specifies the Most Significant Bits (MSB) of the frame number of the reference BTS corresponding to the GANSS Measurement Information or Location Estimate. Starting from the complete GSM frame number denoted FN, the MS calculates Reference FN MSB as

Reference FN MSB = floor(FN/42432)

The complete GSM frame number FN can then be reconstructed in the SMLC by combining the fields Reference Frame with Reference FN MSB in the following way

FN = Reference FN MSB*42432+Reference FN

Range: 0-63

Table A.10.2: Reference Frame field contents

Parameter	# of Bits	Resolution	Range	Unit	Incl.
Reference FN	16	—	0 – 65535	frame	M
Reference FN MSB	6	—	0 – 63	frame	O

GANSS TOD

This field specifies the time for which the location estimate is valid, rounded down to the nearest integer millisecond. This field is optional but shall be included if GANSS TOD – GSM time association is included in which case the MS shall align GANSS TOD with the reported GSM frame boundary observed by the MS at that time. The time reference of GANSS TOD is indicated by GANSS_TIME_ID.

Table A.10.3: GANSS TOD contents

Parameter	# of Bits	Resolution	Range	Unit
GANSS TOD	22	1	0 – 3599999	ms

The 22 bits of GANSS TOD are the least significant bits. The most significant bits shall be derived by the SMLC to unambiguously derive the GANSS TOD.

GANSS TOD Frac

This field is the submillisecond part of the GANSS time of day. This field together with the GANSS TOD field provides a more accurate time stamp of the Location Estimate having resolution of ~61 ns. This field is optional but shall be included if GANSS TOD – GSM time association is included.

Table A.10.4: GANSS TOD Frac contents

Parameter	# of Bits	Resolution	Range	Unit
GANSS_TOD_Frac	14	2^-14	0 – (1-2^-14)	ms

GANSS TOD Uncertainty

This parameter provides the accuracy of the relation between GANSS TOD and GSM time if GANSS TOD- GSM time association is provided. When GANSS TOD-GSM time association is not provided, this element can be included to provide the accuracy of the reported GANSS TOD.

The uncertainty r, expressed in microseconds, is mapped to a number K, with the following formula:

r = C*(((1+x)^K)-1)

with C = 0,0022 and x = 0,18. With 0 £ K £ 127, a suitably useful range between 0 and 3 second is achieved for the uncertainty, while still being able to code down to values as small as 0,3 nanoseconds. To encode any higher value of uncertainty than that corresponding in the above formula to K=127, the same value, K=127, shall also be used. The uncertainty is then coded on 7 bits, as the binary encoding of K.

Table A.10.5: Example values for the GANSS TOD Uncertainty Parameter Format

Value of K	Value of uncertainty
0	0 nanoseconds
1	0,396 nanoseconds
2	0,863 nanoseconds
–	–
50	8,64 microseconds
–	–
127	≥ 2,96 seconds

GANSS_TIME_ID

This field indicates which GNSS has been used as the time reference for GANSS Location Information. This field is optional and absence of this field means that Galileo system time is used as time reference.

Table A.10.6: GANSS_TIME_ID

GANSS_TIME_ID	Indication
GPS	0
QZSS	1
GLONASS	2
BDS	3
Reserved for future use	4-7

Fix Type

This field contains an indication as to the type of measurements performed by the MS: 2D or 3D. This field is mandatory.

‘0’ = 2D fix.

‘1’ = 3D fix.

Position Data

This element provides a list of positioning methods and satellite systems used to calculate the Position Estimate. Each bit of this bitmap is of type Boolean, where TRUE (‘1’) means the particular positioning method or signal(s) from a satellite system has been used.

‘bit 0’: E-OTD;

‘bit 1’ GPS;

‘bit 2’: Galileo;

‘bit 3’: SBAS;

‘bit 4’: Modernized GPS;

‘bit 5’: QZSS;

‘bit 6’: GLONASS;

‘bit 7’: BDS;

‘bit 8-15’: Reserved.

Stationary Indication

This field indicates whether the MS is stationary (horizontal and vertical speeds less than the resolution of the Velocity Estimate parameters as defined in 3GPP TS 23.032).

If Velocity Estimate is requested and the MS is stationary, then the Stationary Indication is set to ‘1’ and Velocity Estimate may not be included in Measure Position Response Element.

Position Estimate

This field contains the calculated position estimate in the format defined in 3GPP TS 23.032. The allowed shapes are:

– ellipsoid Point;

– ellipsoid point with uncertainty circle;

– ellipsoid point with uncertainty ellipse;

– ellipsoid point with altitude and uncertainty ellipsoid.

As defined in 3GPP TS 23.032, the position estimate is provided in WGS-84 reference system.

A.3.2.10 GANSS Measurement Information Element

The purpose of the GANSS Measurement Information element is to provide GANSS measurement information from the MS to the SMLC and GANSS TOD – GSM time association if requested by the SMLC. This information includes the measurements of code phase, Doppler, C/N_o and optionally accumulated carrier phase, also called accumulated deltarange (ADR), which enable the network-based GANSS method where position is computed in the SMLC. The contents are shown in table A.10.7, and the individual fields are described subsequently. See also Figure A.1a for an illustration of the relation between some of the fields.

Figure A.1a. Exemplary definitions of GANSS measurement information fields.

GANSS Measurement Information element is included in the Measure Position Response component if the network has requested the mobile to perform mobile-assisted location measurements using GANSS Positioning Method. GANSS Measurement Information element will also optionally include carrier phase measurements if SMLC has requested the MS to perform carrier phase measurements.

The following fields are repeated the number of times indicated in Number of E-OTD/GPS/GANSS Measurement Sets field if Multiple Sets element is included. If Multiple Sets element is not included, the default value for sets is one (i.e. the following fields are present only once).

Table A.10.7: GANSS Measurement Information element content

Element fields	Presence	Occurrences
Reference Frame	O	1
GANSS TOD	O (note 1)	1
DeltaTOD	O	1
GANSS TOD Uncertainty	O	1
GANSS Generic Measurement Information	M	N_GANSS
NOTE 1: If GPS Measurement Information element is not included in a Measure Position Response component, this field shall be present.

The following paragraphs describe the content of each information field of this element.

Reference Frame

These fields are shown in Table A.10.8 and are optional, but shall be included when GANSS TOD- GSM time association is provided.

Note that expected values for Reference FN are in range 0 – 42431. The time of the reference frame boundary is as observed by the MS, ie without Timing Advance compensation.

Reference FN MSB field indicates the Most Significant Bits (MSB) of the frame number of the reference BTS corresponding to the GANSS Measurement Information.

Starting from the complete GSM frame number denoted FN, the MS calculates Reference FN MSB as

Reference FN MSB = floor(FN/42432)

The complete GSM frame number FN can then be reconstructed in the SMLC by combining the fields Reference Frame with Reference FN MSB in the following way

FN = Reference FN MSB*42432+Reference FN

Table A.10.8: Reference Frame field contents

Parameter	# of Bits	Resolution	Range	Unit
Reference FN	16	—	0 – 65535	frame
Reference FN MSB	6	—	0 – 63	frame

GANSS TOD

This field specifies the GANSS TOD for which the GANSS Measurement Parameters in GANSS Generic Measurement Information Element are valid. This field shall be included when GANSS TOD-GSM time association is provided or if GPS Measurement Information element is not present in a Measure Position Response component. If GPS Measurement Information element is present in a Measure Position Response component, and GANSS TOD field is absent in the GANSS Measurement Information element, the GPS TOW included in the GPS Measurement Information element specifies the reference time for which the GANSS Measurement Parameters are valid.

The 22 bits of GANSS TOD are the least significant bits. The most significant bits shall be derived by the Serving Mobile Location Centre to unambiguously derive the GANSS TOD.

The value for GANSS TOD is derived from the GNSS specific system time of the GNSS reported first in the GANSS Measurement IE rounded down to the nearest millisecond unit.

Table A.10.9: GANSS TOD field contents

Parameter	# of Bits	Resolution	Range	Units
GANSS TOD	22	1 ms	0 – 3599999	ms

DeltaTOD

This field specifies the difference in milliseconds between GANSS TOD reported in the GANSS Measurement Information Element and the millisecond part of the SV time tsv_1 of the first SV in the list reported from the MS. The DeltaTOD is defined as

DeltaTOD = GANSS TOD – fix(tsv_1)

where fix() denotes rounding to the nearest integer towards zero.

Range: 0-127

GANSS TOD Uncertainty

This element provides the accuracy of the relation GANSS TOD -GSM time when GANSS TOD-GSM time association is provided. When GANSS TOD-GSM time association is not provided, even if GANSS TOD – GSM Time Association Measurement Request is not included in the Measure Position Request, this element can be included to provide the accuracy of the reported GANSS TOD.

If GANSS TOD is the given GNSS time, then the true GNSS time, corresponding to the provided GSM time as observed at the MS location, lies in the interval (GANSS TOD – GANSS TOD Uncertainty, GANSS TOD + GANSS TOD Uncertainty).

The uncertainty r, expressed in microseconds, is mapped to a number K, with the following formula:

r = C*(((1+x)^K)-1)

Examples of GANSS TOD Uncertainty value are shown in Table A.10.10.

Table A.10.10: Example values for the GANSS TOD-GSM Time Uncertainty Parameter Format

Value of K	Value of uncertainty
0	0 nanoseconds
1	0,396 nanoseconds
2	0,863 nanoseconds
–	–
50	8,64 microseconds
–	–
127	≥ 2,96 seconds

N_GANSS, Number of GANSS Generic Measurement Information Elements

N_GANSS specifies the number of GANSS Generic Measurement Information Element occurrences in GANSS Measurement Information element, one occurrence for each reported GANSS. The range is from 1 to 8.

A.3.2.10.1 GANSS Generic Measurement Information Element

Table A.10.11: GANSS Generic Measurement Information

Element fields	Presence	Occurrences
GANSS ID	O (note 1)	1
GANSS Generic Measurement Element	M	N_SGN_TYPE
Note 1: Absence of this field means Galileo.

GANSS ID

GANSS ID field identifies the GNSS constellation on which GANSS Measurement Parameters were measured according to Table A.40.

Range: 0 – 7

N_SGN_TYPE, Number of GANSS Generic Measurement Elements

N_SGN_TYPE specifies the number of GANSS Generic Measurement Element occurrences in GANSS Generic Measurement Information element. The range for N_SGN_TYPE is from 1 to 8.

Table A.10.12: GANSS Generic Measurement Element contents

Element fields	Presence	Occurrences
GANSS Signal ID	M	1
GANSS Code Phase Ambiguity	O	1
GANSS Measurement Parameters	M	N_SGN

This element contains measurement information for one GNSS signal type indicated by GANSS Signal ID.

GANSS Signal ID

GANSS Signal ID field identifies the signal on which GANSS Measurement Parameters were measured. The supported signals are listed in Table A.59.

Range: 0 – 7

GANSS Code Phase Ambiguity

The GANSS Code Phase Ambiguity field gives the ambiguity of the code phase measurement. It is given in ms and is an integer between 0 and 127.

The Total Code Phase for a satellite k (Satk) is given modulo this GANSS Code Phase Ambiguity and is reconstructed with :

Code_Phase_Tot(Satk) = Code_Phase (Satk)+ Integer Code Phase(Satk) + n * Code Phase Ambiguity, n= 0,1,2,…

If there is no code phase ambiguity, the GANSS Code Phase Ambiguity shall be set to 0.

The field is optional. If GANSS Code Phase Ambiguity is absent, the default value is 0.

N_SGN, Number of Signal Measurements

N_SGN specifies the number of GANSS Measurement Parameters element occurrence in GANSS Generic Measurement Information element. Typical range for N_SGN is 4 to a maximum of 16.

GANSS Measurement Parameters

Table A.10.13: GANSS Measurement Parameters field contents

Parameter	# of Bits	Resolution	Range	Units	Incl.
Signal Quality Parameters
SV ID	6	—	–	—	M
C/N_o	6	1	0 – 63	dB-Hz	M
Multipath Indicator	2	—	See Table A.9	—	M
Carrier Quality Indication	2	—	—	—	O⁽¹⁾
Code Phase Measurements
Code Phase	21	2^-21	0 – (1-2^-21)	ms	M
Integer Code Phase	7	1	0 – 127	ms	O
Code Phase RMS Error	6	3 bit mantissa 3 bit exp	0,5 – 112	m	M
Doppler Frequency Measurements
Doppler	16	0,04	1310,7	m/s	O
ADR	25	2^-10	0 – 32767,5	m	O⁽¹⁾
NOTE 1: All of these fields shall be present together, or none of them shall be present.

SV ID

The SV ID is an index number for a satellite within a satellite system. The SV ID value range starts from 0 for each satellite system. The interpretation of SV ID for each GANSS is defined in Table A.10.14.

Table A.10.14: Interpretation of SV ID

System

Value of SV ID

Interpretation of SV ID

Galileo

‘0’ – ’35’

’36’ – ’63’

Code No. 1 to 36

Reserved

Modernized GPS

‘0’ – ’62’

’63’

Satellite PRN Signal No. 1 to 63

Reserved

SBAS

‘0’ – ’38’

’39’ – ’63’

Satellite PRN Signal No. 120 to 158

Reserved

QZSS

‘0’ – ‘4’

‘5 – ’63’

Satellite PRN Signal No. 193 to 197

Reserved

GLONASS

‘0’ – ’23’

’24 – ’63’

Slot Number 1 to 24

Reserved

BDS

‘0’ – ’36’

’37’ – ’63’

Satellite ranging code number signal No.1 to 37 [18]

Reserved

C/N₀

This field contains the estimate of the carrier-to-noise ratio of the received signal from the particular satellite. It is given in whole dB-Hz and has a range of 0 to 63. Typical levels observed by GNSS receivers will be in the range of 16 dB-Hz to 50 dB-Hz.

Carrier Quality Indication

This field indicates the quality of a carrier phase measurement as a bit field. The LSB indicates the data polarity, that is. if the data from a specific satellite is received inverted, this is indicated by setting the LSB value to ‘1’. In the case the data is not inverted, the LSB is set to ‘0’. The MSB indicates if accumulation of the carrier phase has been continuous, that is, without cycle slips since the previous measurement report. If the carrier phase accumulation has been continuous, the MSB value is set to ‘1X’. Otherwise, the MSB is set to ‘0X’.

This field is optional and shall be included only when carrier phase measurements are requested.

Table A.10.16: Carrier Phase Quality Indication values and associated indications

Bit	Polarity Indication
‘0’	Data Direct
‘1’	Data Inverted
‘0X’	Carrier phase not continuous
‘1X’	Carrier phase continuous
X = do not care

Code Phase

This field contains the whole and fractional value of the code-phase measurement made by the MS for the particular satellite signal at the time of measurement in the units of ms. GNSS specific code phase measurements (e.g. chips) are converted into unit of ms by dividing the measurements by the nominal values of the measured signal chipping rate (e.g. Galileo L1 OS measurement is divided by 1023,0 chip/ms).

Integer Code Phase

This field indicates the integer millisecond part of the code phase that is expressed modulo the GANSS Code PhaseAmbiguity.

The value of the ambiguity is given in the GANSS Ambiguity field of the GANSS Generic Measurement Information element.

The Integer code phase is optional. The default value is 0.

Code Phase RMS Error

This field contains Code Phase RMS Error value. This parameter has the same range as described in Table A.10.

Doppler

This field contains the Doppler measured by the MS for the particular satellite signal. This information can be used to compute the 3-D velocity of the MS.

The Doppler range is sufficient to cover the potential range of values measured by the MS. Doppler measurements are converted into unit of m/s by multiplying the Doppler measurement in Hz by the nominal wavelength of the measured signal.

ADR

This field contains the ADR measurement measured by the MS for the particular satellite signal. This information can be used to compute the 3-D velocity or high-accuracy position of the MS. ADR measurements are converted into units of m by multiplying the ADR measurement by the nominal wavelength of the measured signal.

This field is optional and shall be included only when carrier phase measurements are requested.