BRAS-3 (RS-10)
 | |
|---|---|
| Frequencies | 1.685 MHz,1.712 MHz,1.774 MHz,1.791 MHz,1.816 MHz,2.107 MHz |
| Frequency Range | 1.685 MHz - 2.107 MHz |
| Mode | AM |
| Modulation | AM,Pulse |
| ACF | — |
| Emission Designator | — |
| Bandwidth | 14 kHz |
| Location | Russia |
| Short Description | BRAS-3 and the closely related RS-10 are Russian medium frequency hyperbolic navigation systems used for marine navigation |
| I/Q Raw Recording | — |
| Audio Sample | |
BRAS-3 and the closely related RS-10 are Russian medium frequency hyperbolic navigation systems designed mainly for marine navigation. Information about these systems, especially RS-10, is scarce. It is known that the systems are deployed as "chains" of three stations, each with one master and two slave stations which transmit pulsed signals in a rather complex sequence. As of 2026, most chains have been decommissioned. At least one chain is still operational somewhere in the Baltic Sea area, likely in Kaliningrad. [1]
The system is said to have range of 200 km or more, and accuracy of 12 to 60 meters. Transmitter output power is said to be only 15 watts. [2]Samples[edit]
These samples are in AMAmplitude Modulation mode and show different types of signals. See the description for different frequencies below.
| 1791 kHzKiloHertz (kHz) 10^3 Hz (assumed positioning frequency) |
1816 kHzKiloHertz (kHz) 10^3 Hz (assumed "command and control" frequency) |
1774 kHzKiloHertz (kHz) 10^3 Hz (assumed sync frequency) |
|---|---|---|
| |
 |
 |
Sometimes there are more than one beep to be heard in one transmit cycle. They are likely coming from different stations of the same chain as the stations transmit in different sequences. If propagation changes it's also changed which stations are heard. USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables) samples are included below, these samples are weak and it may be easier to hear multiple stations with USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables). It must be noted that the sync frequency (description below) is only used by one station in the chain.
| Multiple stations heard on 2107 kHzKiloHertz (kHz) 10^3 Hz | Multiple stations heard on 1816 kHzKiloHertz (kHz) 10^3 Hz |
|---|---|
 |
 |
Frequencies[edit]
At least the following frequencies are active:
| Frequency | Transmit cycle (typically observed) |
Note |
|---|---|---|
| 1685 kHzKiloHertz (kHz) 10^3 Hz | 0.47 sec | Assumed f1 |
| 1712 kHzKiloHertz (kHz) 10^3 Hz | 0.47 sec | Assumed f4 |
| 1774 kHzKiloHertz (kHz) 10^3 Hz | 0.94 sec | Assumed fsync |
| 1791 kHzKiloHertz (kHz) 10^3 Hz | 0.47 sec | Assumed f3 |
| 1816 kHzKiloHertz (kHz) 10^3 Hz | 0.94 sec | Assumed fks |
| 2107 kHzKiloHertz (kHz) 10^3 Hz | 0.47 sec | Assumed f2 |
Each chain uses six frequencies in total. Four (f1, f2, f3, f4) are used to determine position and are transmitted from all stations, one is used for (fks) for "command and control" and is also transmitted from all stations, and one (fsync) is transmitted only from the master station to synchronize oscillators at the slave stations. Transmission sequences are described in [2]. Frequencies are derived from a reference oscillator according to specified formula.
In total, there are 23 possible reference frequencies, from which 23 such frequency sets of six, or "channels", can be derived. A table of all possible frequency sets is available in [2] and also shown in image below. It is not stated anywhere if these are center frequencies. If they are, the active frequencies listed above can be matched roughly to channel 17 although not all frequencies match accurately.
Video Examples[edit]
- Russian BRAS-3 Hyperbolic Radio Navigation Signal | Signal Phantom
- Bike DXer: Strange beeps on MF - The Russian BRAS-3 MF Positioning System
Additional Links[edit]
Additional Images[edit]
|
|
