8 Description of Velocity

23.0323GPPRelease 16TSUniversal Geographical Area Description (GAD)

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

A description of velocity is applicable to any target entity on or close to the surface of the WGS84 ellipsoid.

8.1 Horizontal Velocity

Horizontal velocity is characterised by the horizontal speed and bearing. The horizontal speed gives the magnitude of the horizontal component of the velocity of a target entity. The bearing provides the direction of the horizontal component of velocity taken clockwise from North.

Figure 11: Description of Horizontal Velocity with Uncertainty

8.2 Horizontal and Vertical Velocity

Horizontal and vertical velocity is characterised by horizontal speed, bearing, vertical speed and direction. The horizontal speed and bearing characterise the horizontal component of velocity. The vertical speed and direction provides the component of velocity of a target entity in a vertical direction.

8.3 Horizontal Velocity with Uncertainty

Horizontal velocity with uncertainty is characterised by a horizontal speed and bearing, giving a horizontal velocity vector V, and an uncertainty speed s. It describes the set of velocity vectors v related to the given velocity V as follows:

|v – V|  s

Figure 12: Description of Horizontal Velocity with Uncertainty

8.4 Horizontal and Vertical Velocity with Uncertainty

Horizontal and vertical velocity with uncertainty is characterised by a horizontal speed and bearing, giving a horizontal velocity vector V_x,y, a vertical speed and direction giving a vertical velocity component V_z,and uncertainty speeds s1 and s2. It describes the set of velocity vectors v with horizontal and vertical components v_x,y, and v_z that are related to the given velocity components V_x,y, and V_z as follows:

|v_x,y, – V_x,y, |  s1

|v_z– V_z|  s2

8.5 Coding Principles

Velocity is encoded as shown in Figure 13. The velocity type in bits 8-5 of octet 1 defines the type of velocity information in succeeding bits.

Figure 13: General Coding of Velocity

8.6 Coding of Velocity Type

Table 3 shows the coding of the velocity type.

Table 3: Coding of Velocity Type

Bits
4 3 2 1
0 0 0 0	Horizontal Velocity
0 0 0 1	Horizontal with Vertical Velocity
0 0 1 0	Horizontal Velocity with Uncertainty
0 0 1 1	Horizontal with Vertical Velocity and Uncertainty
other values	reserved for future use

8.7 Coding of Horizontal Speed

Horizontal speed is encoded in increments of 1 kilometre per hour using a 16 bit binary coded number N. The relation between the number N and the horizontal speed h (in kilometres per hour) it encodes is described by the following equations:

N  h < N + 0.5 (N = 0)

N – 0.5  h < N + 0.5 (0 < N < 2¹⁶-1)

N – 0.5  h (N = 2¹⁶-1)

8.8 Coding of Bearing

Bearing is encoded in increments of 1 degree measured clockwise from North using a 9 bit binary coded number N. The relation between the number N and the bearing b (in degrees) it encodes is described by the following equation:

N  b < N+1

except for 360  N < 511 which are not used.

8.9 Coding of Vertical Speed

Vertical speed is encoded in increments of 1 kilometre per hour using 8 bits giving a number N between 0 and 2⁸-1. The relation between the number N and the vertical speed v (in kilometres per hour) it encodes is described by the following equations:

N  v < N + 0.5 (N = 0)

N – 0.5  v < N + 0.5 (0 < N < 2⁸-1)

N – 0.5  v (N = 2⁸-1)

8.10 Coding of Vertical Speed Direction

Vertical speed direction is encoded using 1 bit: a bit value of 0 indicates upward speed; a bit value of 1 indicates downward speed.

8.11 Coding of Uncertainty Speed

Uncertainty speed is encoded in increments of 1 kilometre per hour using an 8 bit binary coded number N. The value of N gives the uncertainty speed except for N=255 which indicates that the uncertainty is not specified.

8.12 Coding of Horizontal Velocity

The coding of horizontal velocity is described in figure 14.

Figure 14: Coding of Horizontal Velocity

Bearing

Bit 1 of octet 1 is the high order bit; bit 1 of octet 2 is the low order bit

Horizontal Speed

Bit 1 of octet 4 is the low order bit

8.13 Coding of Horizontal with Vertical Velocity

The coding of horizontal with vertical velocity is described in figure 15.

Figure 15: Coding of Horizontal with Vertical Velocity

D: Direction of Vertical Speed

Bit value 0 Upward

Bit value 1 Downward

8.14 Coding of Horizontal Velocity with Uncertainty

The coding of horizontal velocity with uncertainty is described in figure 16.

Figure 16: Coding of Horizontal Velocity with Uncertainty

8.15 Coding of Horizontal with Vertical Velocity and Uncertainty

The coding of horizontal with vertical velocity and uncertainty is described in figure 17.

Figure 17: Coding of Horizontal with Vertical Velocity and Uncertainty

Annex A (informative):
Element description in compact notation

The notation is the one described in GSM 04.07 [2].

<Geographical Area Description> ::=

<Point> |

<Point with uncertainty circle > |

<Point with uncertainty ellipse> |

<Polygon> |

<Point with Altitude> |

<Point with altitude and uncertainty ellipsoid> |

<Arc>;

<Point> : :=

0000 <spare>(4)

<Point horizontal co-ordinates> ;

<point horizontal co-ordinates> ::=

<Longitude : bit string(24)> ;

<Point with uncertainty circle > ::=

0001 <spare>(4)

<spare bit> <Uncertainty: bit string(7)> ;

<Point with uncertainty ellipse> ::=

0011 <spare>(4)

<spare bit> <Confidence: bit string(7)>;

<Polygon> ::=

0101 <Number of points>

<Point co-ordinates>(val(Number of points)) ;

<Number of points> ::=

0011 | 0100 | 0101 | 0110 | 0111 | 1000 | 1001 | 1010 |

1011 | 1100 | 1101 | 1110 | 1111 ;

<Point with Altitude> ::=

1000 <spare>(4)

<Point vertical co-ordinate>;

<point vertical co-ordinate> ::=

<Point with altitude and uncertainty ellipsoid> ::=

1001 <spare>(4)

<spare bit> <Confidence: bit string(7)>;

<Ellipsoid Arc> ::=

<1010> spare(4)

<Spare bit> <Uncertainty radius: bit string(7)>;

<spare bit> <Confidence: bit string(7)>;

<Velocity Description> ::=

<Horizontal Velocity> |

<Horizontal and Vertical Velocity> |

<Horizontal Velocity with Uncertainty>|

<Horizontal and Vertical Velocity with Uncertainty>;

<Horizontal Velocity> : :=

0000 <spare>(3)

<Bearing: bit string(9)>

<Horizontal speed: bit string(16)>;

<Horizontal and Vertical Velocity> : :=

0001 <spare>(2)

<Bearing: bit string(9)>

<Vertical speed: bit string(8)>;

<Horizontal Velocity with Uncertainty> : :=

0010 <spare>(3)

<Bearing: bit string(9)>

<Uncertainty Speed: bit string(8)>;

<Horizontal and Vertical Velocity with Uncertainty> : :=

0011 <spare>(2)

<Bearing: bit string(9)>

<Vertical Uncertainty Speed: bit string(8)>;

Annex B (informative):
Change history

Change history
Date	Meeting	TD	CR	Rev	Cat	Subject/Comment	New version
2004-12	SP-26					Created version 6.0.0	6.0.0
2007-06	SP-36	–	–	–		Update to Rel-7 version (MCC)	7.0.0
2008-12	SP-42	–	–	–		Update to Rel-8 version (MCC)	8.0.0
2009-12	SP-46	–	–	–		Update to Rel-9 version (MCC)	9.0.0
2011-03	SP-51	–	–	–	–	Update to Rel-10 version (MCC)	10.0.0
2012-09	–	–	–	–	–	Update to Rel-11 version (MCC)	11.0.0
2014-09	SP-65	–	–	–	–	Update to Rel-12 version (MCC)	12.0.0
2015-12	–	–	–	–	–	Update to Rel-13 version (MCC)	13.0.0
2017-03	–	–	–	–	–	Update to Rel-14 version (MCC)	14.0.0
2018-03	SP-79	SP-180089	0014	–	F	Correction to the speed encoding	14.1.0
2018-06	SP-80	–	–	–		Update to Rel-15 version (MCC)	15.0.0
2018-09	SP-81	SP-180729	0015	1	F	GAD shape(s) for high accuracy positioning	15.1.0
2020-07	SP-88E	–	–	–	–	Update to Rel-16 version (MCC)	16.0.0
2021-12	SP-94E	SP-211279	0020	1	F	Introducing new high accuracy GAD shape with scalable uncertainty	16.1.0