1. Voice compression and decompression library
The voice compression and decompression library is an important function of the Vanastar Beidou open platform. It breaks through the high compression ratio voice coding and decoding technology, designs a low-latency voice data scheduling protocol, and realizes point-to-point continuous voice intercom between users, and users Real-time feedback between the background and the user.
Under the condition of conventional narrow-width satellite communication, the communication capacity is very limited. Generally speaking, only text messages can be sent, and the efficiency of emergency communication is extremely low, which cannot meet the actual application requirements. However, the current Vanadium Beidou open platform has successfully upgraded the voice compression and decompression library to the voice communication stage. Input the voice message through the APP of the sending end, and send the short message to the Beidou satellite after processing, and the receiving end can directly play the voice after receiving the short message.
Feature highlights:
1. Extreme compression ratio
The sampling rate is 8kHz, and the code rate is 450bps. When using the BDS-3 level 5 card (1750 bytes), the longest voice can be transmitted for 31 seconds.
2. Ultra-high compression efficiency
From voice input to compression, the whole process only takes 200 milliseconds.
3. High fidelity effect
The wave speed of integrated learning forms a voice enhancement algorithm, which can clearly distinguish male or female voices and identify the identity of the user.
Technical highlights:
1. Unvoiced/voiced sound judgment technology in speech transition
The pitch period estimation algorithm based on upsampling, the clear/voiced sound judgment in the transition period, and the asymmetric window LPC analysis method based on the transition period can effectively improve the voice quality.
2. Speech enhancement algorithm combining beamforming and deep learning
Using complex Gaussian mixture model to estimate time-frequency masking and beamforming method of direction vector, it can effectively remove environmental noise and enhance speech effect.
3. Efficient and reliable voice transmission protocol optimization technology in low bit rate environment
Anti-long-delay voice transmission protocol based on coding redundancy; dynamic packetization algorithm for adaptive channel rate; intelligent scheduling strategy for link resources based on genetic algorithm. Effectively support lost packet retransmission, support user dynamic adjustment, and improve transmission efficiency.
Voice demonstration video of short message sending in BDS-3 area
Beidou Handheld Voice Transceiver Demonstration Video-Pan Cobalt v0.2-20220428
Application field
-
Forest fire emergency location tracking
-
Geopark satellite voice one-key call
-
Tactical Communication Command and Dispatch
-
Power inspection emergency communication
2. Beidou SDK application
At present, the Beidou SDK application has covered Android mobile phones, Apple mobile phones, Beidou short message all-in-one machines and PCs. Developers can realize common operations such as sending and receiving Beidou short messages by integrating the provided Beidou SDK, which greatly saves developers Research and development time, improve research and development efficiency. Moreover, it supports RDSS short message communication and RNSS positioning products, supports Beidou-2 protocols 4.0 and 2.1, supports Beidou-3 protocols, and can perfectly run on various forms of Beidou products, such as vehicle-mounted terminals, ship-borne terminals, and Beidou boxes.
Feature highlights:
1. Perfectly adapt to multiple hardware
ios, android terminal mobile phone, Android tablet, PC terminal, etc. have been covered
2. Mature Beidou application
Support RDSS short message communication and RNSS positioning products, support BDS-2 4.0 and 2.1 protocols, and BDS-3 protocols
3. Continuous iterative update
Stable product updates, continuous iteration, keeping up with the development of Beidou
The communication role of Beidou short message has gradually expanded in people's daily life. It does not rely on the traditional three-network signal. It is very powerful in weak signal areas, no signal areas or harsh environments with communication signals. Powerful, providing more convenient and intelligent Beidou services for the people of the whole country.