LabSat 3 Wideband Signal Descriptions - SatGen 4
SatGen 4 Wideband can create signals in the upper and lower L band and will take advantage of the LabSat 3 Wideband unit's ability to read RF data at up to 95 MB/s.
SatGen 4 can create the following signals:
| Signal | Description |
|---|---|
|
GPS L1 C/A |
This signal is transmitted by all GPS satellites on the L1 (1575.42 MHz) frequency. It is the most important signal for civilian applications and it is accepted by a huge majority of GNSS receivers around the globe. |
|
GPS L1 P & GPS L2 P |
This signal is transmitted by all GPS satellites on the L1 (1575.42 MHz) and the L2 (1227.6 MHz) frequencies. They are precision military signals that are normally encrypted and referred to as the P(Y) code. The encryption algorithm is classified, but receiver manufacturers managed to develop special codeless or semi-codeless techniques to acquire L1P(Y) and L2P(Y). The position accuracy is improved, because dual-frequency receivers can measure the difference between signal reception times between the two frequencies and calculate the exact value of the ionospheric delay (which is the main source of error). All receivers that accept the P(Y) code will also accept the unencrypted P code simulated by SatGen. |
|
GPS L2 transmitted |
This signal is transmitted by GPS IIR-M and newer satellites on the L2 (1227.6 MHz) frequency. It is the second most important civilian signal. The fact that it is transmitted on a different frequency than L1C/A makes it possible to measure the ionospheric delay to improve accuracy. Dual-frequency civilian receivers can now provide the same level of accuracy as military receivers that use L1P(Y) and L2P(Y). |
|
GPS L5 |
This signal is transmitted by GPS IIF and newer satellites on the L5 (1176.45 MHz) frequency. It is a signal intended for life-critical applications, such as aircraft precision approach guidance. It consists of two signals (L5 I and L5 Q) transmitted on the same frequency. The L5 I signal is modulated by the navigation message. The L5 Q signal does not carry any data. |
|
GPS L1 M & GPS L2 M |
This signal is transmitted by GPS IIR-M and newer satellites on the L1 (1575.42 MHz) and the L2 (1227.6 MHz) frequencies. They are modernised military signals intended to eventually replace L1P(Y) and L2P(Y). Very little has been published about them, but the modulation details are known and SatGen can transmit random data using the BOCsin (10,5) modulation and create signals matching the M-Code spectral characteristics. |
|
GALILEO E1 B/C |
This signal is transmitted by all Galileo satellites on the E1 (1575.42 MHz) frequency (the same as GPS L1). It is a standard precision open service signal that consists of Data component B and Pilot component C. |
|
GALILEO E5a |
This signal is transmitted by all Galileo satellites on the E5a (1176.45 MHz) frequency, (the same as GPS L5). It is an open service signal that consists of Data component I (with the F/NAV navigation message) and Pilot component Q. It is intended to be used with E1 B/C to improve accuracy. |
|
GALILEO E5b |
This signal is transmitted by all Galileo satellites on the E5b (1207.14 MHz) frequency, (the same as BeiDou B2). It is an open service signal that consists of Data component I (with the I/NAV navigation message) and Pilot component Q. It is intended to be used with E1 B/C to improve accuracy. |
|
GALILEO E6 B/C |
This signal is transmitted by all Galileo satellites on the E6 (1278.75 MHz) frequency. It is a high-accuracy commercial service signal that consists of Data component B and Pilot component C. Since the content of the C/NAV navigation message is encrypted, SatGen transmits a dummy navigation message, that should be accepted by all receivers. |
|
GLONASS L1 OF |
This signal is transmitted by all GLONASS satellites on the GLONASS L1 frequency band (14 channels around the nominal frequency of 1602 MHz). It is a standard precision civilian signal that is more suitable for navigation in polar regions thanks to the more inclined orbits of GLONASS satellites. |
|
GLONASS L2 OF |
This signal is transmitted by GLONASS-M and newer satellites on the GLONASS L2 frequency band (14 channels around the nominal frequency of 1246 MHz). It is a standard precision civilian signal, identical to L1 OF (but with smaller channel spacing). The fact that it is transmitted on a different frequency band than L1 OF makes it possible to use a dual-frequency receiver to measure the ionospheric delay to improve accuracy. |
|
BEIDOU B1l |
This signal is transmitted by all BeiDou satellites on the B1 (1561.098 MHz) frequency. It is a standard precision civilian signal that is very similar to GPS L1C/A. |
|
BEIDOU B2I |
This signal is transmitted by all BeiDou satellites on the B2 (1207.14 MHz) frequency. It is a standard precision civilian signal identical to B1I. The fact that it is transmitted on a different frequency than B1I makes it possible to use a dual-frequency receiver to measure the ionospheric delay to improve accuracy. |
|
BEIDOU B3I |
This signal is transmitted by all BeiDou satellites on the B3 (1268.52 MHz) frequency. It is a standard precision civilian signal that is similar to B1I, but it has a chipping rate that is 5 times higher. The fact that it is transmitted on a different frequency than B1I makes it possible to use a dual-frequency receiver to measure the ionospheric delay to improve accuracy. |
|
NAVIC L5 SPS |
This signal is transmitted by all NAVIC (formerly known as IRNSS) satellites on the L5 (1176.45 MHz) frequency (the same as GPS L5 and Galileo E5a). It is a standard precision service and the main public signal of the NAVIC constellation. |
|
NAVIC S SPS |
This signal is transmitted by all NAVIC (formerly known as IRNSS) satellites on the S (2492.028 MHz) frequency. It is a public standard precision service that is very similar to L5 SPS, but transmitted on a different frequency to allow receivers to measure the ionospheric delay and improve accuracy. NAVIC is the only constellation that uses S-band. |
Signals can generally be split into two categories; narrowband and wideband.
- Narrowband: There signals have a modulation (chipping code) frequency of no more than a few megahertz, such as GPS L1C/A (1.023 MHz), GLONASS L1OF (0.511 MHz), BeiDou B1I (2.046 MHz).
- Wideband: These signals use a modulation (chipping code) frequency of 10 megahertz or more, such as GPS L1P (10.23 MHz), GPS L5 (10.23 MHz).
When SatGen 4 Wideband simulates signals transmitted on up to 3 frequencies, the following conditions will apply:
- Each frequency band is transmitted on a different LabSat 3 Wideband output channel.
- For narrowband signals the 10.5 MHz sampling rate and 10 MHz bandwidth are used.
- For wideband signals, a 20 or 30 MHz bandwidth is used depending on the actual signals. If a single wideband signal is present, the output channels will use a high sampling rate.
When SatGen 4 Wideband simulates signals transmitted on more than 3 frequencies:
- The signals transmitted on frequencies that are close to each other are grouped together to form very wide output channels.
- The following groups are examples of groupings:
- L1 with GPS L1C/A, GPS L1P, GPS L1M, GLONASS L1OF and BeiDou B1I.
- L2 with GPS L2C, GPS L2P, GPS L2M, GLONASS L2OF and BeiDou B2I.
To maximise the performance, SatGen 4 will use a sophisticated algorithm to create the correct centre frequency and bandwidth, depending upon the signal required. You can easily check the actual parameters used in the scenario by looking at the .ini file produced alongside the.LS3W scenario file on your PC.