Adaptive satellite-aiming method for low-orbit mobile satellite communication network

Patent metadata

Field	Value
Publication number	US-11764864-B2
Application number	US-201916965008-A
Country	US
Kind code	B2
Filing date	Sep 4, 2019
Priority date	Jun 10, 2019
Publication date	Sep 19, 2023
Grant date	Sep 19, 2023

Abstract

The present disclosure discloses an adaptive satellite-aiming method for a low-orbit mobile satellite communication network. The method first receives signals through an array antenna, estimates an offset angle between an array antenna and a satellite beam using a MUSIC-based angle estimation method; then, based on the estimated offset angle, tracks a satellite direction using the adaptive coupling model and achieves tracking and alignment of an antenna direction based on feature parameters extracted during a tracking process; finally, based on the obtained feature parameters, adjusts parameters in the MUSIC-based angle estimation method, and repeats the above steps, to achieve real-time estimation of the offset angle and real-time tracking and alignment of the antenna direction.

First claim

What is claimed is:

1. An adaptive satellite-aiming method for a low-orbit mobile satellite communication network, comprising:
Step S1: initializing all tracking feature parameters of a local layer and a global layer of an adaptive coupling model;
Step S2: receiving a signal through an array antenna, and estimating an offset angle between an array antenna beam and a satellite beam using a MUSIC-based angle estimation method;
Step S3: tracking a satellite direction using the adaptive coupling model based on the estimated offset angle, and achieving tracking and alignment of an antenna direction based on feature parameters extracted during the tracking of the satellite direction; and
Step S4: adjusting parameters in the MUSIC-based angle estimation method based on the feature parameters obtained in the Step S3, and returning to the Step S2 for achieving real-time estimation of the offset angle and real-time tracking and alignment of the antenna direction;
wherein the Step S1 comprises:
setting an initial value of a search range φ of the array antenna to an entire airspace, and setting an initial value of a number of sampling points as n;
initializing all the tracking feature parameters of the local layer and the global layer of the adaptive coupling model, taking an azimuth angle A(t) and an pitch angle E(t) of the satellite direction and tracking values of angular velocities respectively corresponding to the azimuth angle A(t) and the pitch angle E(t) as parameters of a state matrix X t at time t, setting a tracking interval ΔT, taking time t=0 as a tracking start time, and taking an observation value Y t at the time t=0 as an initial value of the state matrix; and
setting a layering length of the local layer as N, taking observation values [Y t , Y t-1 , . . . , Y t-N+1 ] as a layering feature of the local layer at time t, and setting an initial value of a tracking error P, an initial value of a process error Q, and an initial value of an observation error R of the feature parameters, wherein the initial value of the tracking error P is equal to the initial value of the observation error R.

2. The adaptive satellite-aiming method according to claim 1 , wherein the Step S2 comprises:
Sub-step S2.1: dividing the airspace, and performing spiral spatial scanning on each divided airspace around a beam direction by beamforming within a search range y after determining a beam direction of the array antenna;
Sub-step S2.2: obtaining a received signal X(t) in a scanning direction in which a maximum received signal power has been searched, after one spatial scanning;
Sub-step S2.3: calculating a covariance matrix value R XX of the received signal X(t), then performing eigenvalues decomposing on the covariance matrix value using a following formula to obtain a signal subspace U S and a noise subspace U N ,
R XX =UΣU T =U S Σ S U S T +U N Σ N U N T   (1),

where Σ S and Σ N are eigenvalues of the two subspaces respectively, and T represents a transposition;
Sub-step S2.4: obtaining the offset angle through a following formula in the noise subspace U N ,

θ
MUSIC

=

argmax

θ

[

1

α
⁡
(
θ
)

T

·

U
N

·

U
N
T

⁢

α
⁡
(
θ
)

]

,

(
2
)

where α(θ)=[a 1 , a 2 , . . . , a K ] T represents phase information, and θ MUSIC is a value of 0 when the right function takes a maximum value; and
Sub-step S2.5: obtaining an offset angle θ A of the azimuth angle and an offset angle θ E of the pitch angle through the Sub-steps S2.1 to S2.4, obtaining values of the azimuth angle A(t) and the pitch angle E(t) in the antenna direction through array antenna parameters, and then obtaining the observation value Y t at time t based on:

Y
t

=

[

A
⁡
(
t
)

+

θ
A

E
⁡
(
t
)

+

θ
E

]

.

(
3
)

3. The adaptive satellite-aiming method according to claim 2 , wherein the Step S3 comprises:
Sub-step S3.1: predicting a state matrix X t|t

Assignees

• Univ Zhejiang

Inventors

• Song Chunyi
• Chen Qin
• Xu Yuying
• Xu Zhiwei

Classifications

• H04B7/086 Primary

  using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming · CPC title

• H04B7/195 Primary

  Non-synchronous stations · CPC title

• H04B7/18519 Primary

  Operations control, administration or maintenance · CPC title

• H04B7/1851

  Systems using a satellite or space-based relay (H04B7/18508, H04B7/18521 take precedence; providing specific services H04B7/18523 - H04B7/18576) · CPC title