Location information in non-terrestrial networks

1 . A method for wireless communication at a user equipment (UE), comprising:

establishing a connection between the UE and a network node of a non-terrestrial network;

receiving, from the network node and based at least in part on a type of orbit around Earth of the network node, differential ephemeris information comprising a first value or the first value and a second value associated with a position or a velocity of the network node relative to a terrestrial-based reference; and

communicating with the network node based at least in part on the position or the velocity of the network node, or both, wherein the position or the velocity of the network node is based at least in part on ephemeris information comprising an altitude of the network node, the first value, the second value, and a third value, wherein the third value is computed at the UE based at least in part on the differential ephemeris information received at the UE.

2 . The method of claim 1 , further comprising:

receiving, from the network node, an indication of the altitude of the network node, wherein the indication comprises a value of the altitude, an altitude differential value, or the type of orbit of the network node, wherein the UE derives the altitude when the indication comprises the altitude differential value or the type of orbit of the network node.

3 . The method of claim 1 , further comprising:

determining an absolute value of the third value based at least in part on the first value, the second value, and the altitude of the network node, wherein the first value, the second value, and the third value of the position of the network node comprises geocentric coordinates of the network node in an earth-centered, earth-fixed Cartesian coordinate system.

4 . The method of claim 3 , further comprising:

receiving, from the network node, a correction value of the third value and a sign of the third value;

determining a corrected third value based at least in part on applying the sign and the correction value of the third value to the absolute value of the third value; and

determining the position of the network node relative to the terrestrial-based reference based at least in part on the first value, the second value, the corrected third value, and the altitude of the network node, wherein communicating with the network node is based at least in part on the position of the network node.

5 . The method of claim 1 , further comprising:

receiving, from the network node, a correction value of the altitude of the network node and a sign of the third value;

applying the correction value of the altitude to the altitude of the network node; and

determining the position of the network node based at least in part on applying the correction value of the altitude to the altitude of the network node.

6 . The method of claim 5 , further comprising:

determining an absolute value of the third value based at least in part on the first value, the second value, and the correction value of the altitude applied to the altitude of the network node, wherein communicating with the network node is based at least in part on determining the absolute value of the third value, wherein the first value is of a first coordinate of the network node, the second value is of a second coordinate of the network node, and the third value is of a third coordinate of the network node of a three-coordinate positioning system;

determining a corrected third value based at least in part on applying the sign of the third value to the absolute value of the third value; and

determining the position of the network node relative to the terrestrial-based reference based at least in part on the first value, the second value, the corrected third value, and the altitude of the network node.

7 . The method of claim 1 , further comprising:

receiving, from the network node, a correction value of the altitude of the network node, wherein the altitude of the network node, a reference time, and the first value or the second value, or both, are received in one or more system information blocks or one or more radio resource control messages;

determining a corrected altitude based at least in part on the altitude and the correction value of the altitude; and

determining the position of the network node relative to the terrestrial-based reference based at least in part on the first value, the second value, the third value, and the corrected altitude of the network node.

8 . The method of claim 1 , wherein the first value comprises a first velocity vector of the network node relative to the terrestrial-based reference, the second value comprises a second velocity vector of the network node relative to the terrestrial-based reference, and the third value comprises a third velocity vector of the network node relative to the terrestrial-based reference.

9 . The method of claim 8 , further comprising:

receiving, from the network node, a correction value of the third value and a sign of the third value;

determining an absolute value of the third velocity vector based at least in part on the first velocity vector, the second velocity vector, a gravitational constant, a mass of the Earth, and the altitude of the network node; and

determining a corrected third velocity vector based at least in part on the sign, the correction value of the third value, and the absolute value of the third velocity vector, wherein communicating with the network node is based at least in part on the first velocity vector, the second velocity vector, and the corrected third velocity vector.

10 . The method of claim 8 , further comprising:

receiving, from the network node, a correction value of the third value and a sign of the third value; and

determining an absolute value of the third velocity vector based at least in part on the first velocity vector, the second velocity vector, a first satellite velocity value based at least in part on a gravitational constant, a mass of the Earth, and the altitude of the network node, and a second satellite velocity value based at least in part on an angular speed of the Earth relative to the terrestrial-based reference.

11 . The method of claim 8 , further comprising:

receiving, from the network node, a radial vector of the network node, a tangent vector of the network node, and a velocity vector of the network node;

determining the first velocity vector of the network node, the second velocity vector of the network node, and the third velocity vector of the network node, based at least in part on the radial vector of the network node, the tangent vector of the network node, the velocity vector of the network node; and

determining a relative velocity of the network node based at least in part on the first velocity vector of the network node, the second velocity vector of the network node, and the third velocity vector of the network node, and a velocity of the UE, wherein communicating with the network node is based at least in part on the relative velocity of the network node.

12 . The method of claim 1 , further comprising:

receiving an indication of the type of orbit of the network node, wherein communicating with the network node is based at least in part on receiving the indication of the type of orbit.

13 . The method of claim 1 , further comprising:

identifying the type of orbit of the network node based at least in part on system information associated with the network node, wherein communicating with the network node is based at least in part on identifying the type of orbit.

14 . The method of claim 1 , further comprising:

identifying a round-trip delay between the UE and the network node; and

identifying the type of orbit of the network node based at least in part on the round-trip delay associated with the network node, wherein communicating with the network node is based at least in part on identifying the type of orbit.

15 . The method of claim 1 , wherein the first value comprises a first difference between a current first coordinate of the network node and a target first coordinate of the network node, the second value comprises a second difference between a current second coordinate of the network node and a target second coordinate of the network node and the third value comprises a fixed value based at least in part on the type of orbit of the network node.

16 . The method of claim 15 , further comprising:

determining a first coordinate of the network node based at least in part on the first value, a second coordinate of the network node based at least in part on the second value, and a third coordinate of the network node based at least in part on the fixed value; and

determining the position of the network node relative to the terrestrial-based reference based at least in part on the first coordinate, the second coordinate, and the third coordinate, wherein communicating with the network node is based at least in part on the position of the network node.

17 . The method of claim 1 , further comprising:

receiving information about a second position of a reference network node and receiving an indication of the reference network node associated with the first value and the second value, wherein communicating with the network node is based at least in part on the receiving of information about the second position or receiving the indication of the reference network node, or both, wherein the first value comprises a first difference between the position of the network node and the second position of the reference network node, the second value comprises a second difference between the position of the network node and the second position of the reference network node, and the third value comprises a fixed value based at least in part on the type of orbit of the network node.

18 . The method of claim 1 , further comprising:

receiving a sign of the second value;

determining the second value of the network node based at least in part on the first value received from the network node, a fixed value for the third value, and the altitude of the network node, and

applying the sign to the determined second value.

19 . A method for wireless communication at a user equipment (UE), comprising:

establishing a connection between the UE and a network node of a non-terrestrial network;

receiving, from the network node and based at least in part on a type of orbit around Earth of the network node, a first value or the first value and a second value associated with a position of the network node relative to a terrestrial-based reference, wherein the first value and the second value are associated with a polar coordinate system, and wherein the first value corresponds to an azimuth angle and the second value corresponds to a zenith angle; and

communicating with the network node based at least in part on the position of the network node relative to the terrestrial-based reference, wherein the position of the network node is based at least in part on an altitude of the network node, the first value, and the second value.

20 . The method of claim 19 , further comprising:

receiving, from the network node, an indication of the altitude of the network node, wherein the indication comprises a value of the altitude, an altitude differential value, or the type of orbit of the network node, wherein the UE derives the altitude when the indication comprises the altitude differential value or the type of orbit of the network node.

21 . The method of claim 19 , further comprising:

determining a first angle of the network node based at least in part on the first value and a second angle of the network node based at least in part on the second value; and

determining the position of the network node relative to the terrestrial-based reference based at least in part on the first angle and the second angle, wherein communicating with the network node is based at least in part on the position of the network node, wherein the first value comprises a first difference between a current first angle of the network node and a first target angle of the network node and the second value comprises a second difference between a current second angle of the network node and a second target angle of the network node.

22 . The method of claim 19 , further comprising:

identifying the type of orbit of the network node; and

determining the position of the network node relative to the terrestrial-based reference based at least in part on the first value received from the network node, the second value being a fixed value based at least in part on the type of orbit of the network node, and the altitude of the network node, wherein communicating with the network node is based at least in part on the position of the network node.

23 . The method of claim 19 , wherein:

the terrestrial-based reference comprises a center of the Earth;

the first value comprises the azimuth angle or a longitude angle of the network node relative to the center of the Earth; and

the second value comprises the zenith angle or a latitude angle of the network node relative to the center of the Earth.

24 . The method of claim 19 , further comprising:

receiving, from the network node, an indication of a position of a second network node.

25 . The method of claim 24 , wherein the indication of the position of the second network node comprises the position of the second network node, or a velocity of the second network node, or a reference time of the second network node, or any combination thereof.

26 . The method of claim 24 , wherein the indication of the position of the second network node comprises a differential position of the second network node relative to the network node, or a differential velocity of the second network node relative to the network node, or a differential reference time of the second network node relative to the network node, or any combination thereof.

27 . The method of claim 24 , wherein the indication of the position of the second network node comprises a semi-major axis, or an eccentricity value, or an argument of periapsis, or a longitude of ascending node value, or an inclination value, or a mean anomaly value at an epoch time, or any combination thereof.

28 . The method of claim 24 , wherein the indication of the position of the second network node comprises a differential semi-major axis, or a differential eccentricity value, or a differential argument of periapsis, or a differential longitude of ascending node value, or a differential inclination value, or a differential mean anomaly value at an epoch time, or any combination thereof.

29 . An apparatus for wireless communication at a user equipment (UE), comprising:

a processor;

memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

establish a connection between the UE and a network node of a non-terrestrial network;

receive, from the network node and based at least in part on a type of orbit around Earth of the network node, differential ephemeris information comprising a first value or the first value and a second value associated with a position or a velocity of the network node relative to a terrestrial-based reference; and

communicate with the network node based at least in part on the position or the velocity of the network node, or both, wherein the position or the velocity of the network node is based at least in part on ephemeris information comprising an altitude of the network node, the first value, the second value, and a third value, wherein the third value is computed at the UE based at least in part on the differential ephemeris information received at the UE.

30 . An apparatus for wireless communication at a user equipment (UE), comprising:

a processor;

memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

establish a connection between the UE and a network node of a non-terrestrial network;

receive, from the network node and based at least in part on a type of orbit around Earth of the network node, a first value or the first value and a second value associated with a position of the network node relative to a terrestrial-based reference, wherein the first value and the second value are associated with a polar coordinate system, and wherein the first value corresponds to an azimuth angle and the second value corresponds to a zenith angle; and

communicate with the network node based at least in part on the position of the network node relative to the terrestrial-based reference, wherein the position of the network node is based at least in part on an altitude of the network node, the first value, and the second value.