For high precision orbit determination using radio signals, accuracy is improved by using a pair of frequencies linked by a simple ratio. The ratio is usually 8:3
Both the Soviet and US early navigation systems used linked frequencies near 150 MHz and 400 MHz. These were the "Nadezhda" and "Parus" systems on the Soviet side and the American "Transit" system. Today, the Nadezhda satellites are silent but Parus is still transmitting. Whether Parus is still used for navigation in these days of Glonass and GPS is a moot point. It may be that the satellites serve a different purpose where precise positional details are necessary.
Transit has been turned over to other purposes, coherent transmissions still emanate from the satellites but they are now used for ionospheric studies.
Some Chinese satellites transmit at coherent pairs of frequencies near 180 MHz and 480 MHz, in the 8:3 ratio.
Freq (MHz) |
Satellite |
Payload |
Signal Type |
Notes
|
149.910 |
Cosmos 2398
2003-23A
27818 |
Navigation (+ comms?) |
FM time and position information - sidebands at 3 kHz, 5 kHz and 7 kHz |
Transmission contains an almanac for all active satellites in the constellation
Use for navigation has probably ceased but is still supporting whatever other system requires reasonably precise positional information for the satellites
Coherent transmission at 399.760 MHz |
149.940 |
Cosmos 2378
2001-23A
26818 |
Navigation (+ comms?) |
FM time and position information - sidebands at 3 kHz, 5 kHz and 7 kHz |
Transmission contains an almanac for all active satellites in the constellation
Use for navigation has probably ceased but is still supporting whatever other system requires reasonably precise positional information for the satellites
Coherent transmission at 399.840 MHz |
149.970 |
Cosmos 2389
2002-26A
27436 |
Navigation (+ comms?) |
FM time and position information - sidebands at 3 kHz, 5 kHz and 7 kHz |
Transmission contains an almanac for all active satellites in the constellation
Use for navigation has probably ceased but is still supporting whatever other system requires reasonably precise positional information for the satellites
Coherent transmission at 399.920 MHz |
149.979 |
Oscar 29 (Transit)
1987-80B
18362 |
Ionospheric modelling for US military (NIMS) |
Modulated CW carrier |
Maintenance frequency
Coherent transmission at 399.944 MHz (has been heard to transmit tones similar to the other OSCAR satellite but 2003 December 28 - this frequency was occupied by a modulated 'buzzing' signal
No longer transmitting as of 2008 Feb 1 |
149.979 |
Oscar 31 (Transit)
1988-74B
19420 |
Ionospheric modelling for US military (NIMS) |
FM telemetry (tones) +/- 2.4 kHz from carrier |
Maintenance frequency
Coherent transmission at 399.944 MHz
Occasionally changes between this frequency and the operational one
Sometime between 2007 Dec 21 and 2008 Feb 7, the normal transmissions at both frequencies were replaced with a highly unstable CW carrier (wandering frequency + variations in strength) |
149.988 |
Oscar 23 (Transit)
1988-33A
19070 |
Ionospheric modelling for US military (NIMS) |
FM telemetry (tones) +/- 2.4 kHz from carrier |
Operational frequency
Coherent transmission at 399.968 MHz
Occasionally changes between this frequency and the maintenance one) |
149.988 |
Oscar 25 (Transit)
1988-74A
19419 |
Ionospheric modelling for US military (NIMS) |
FM telemetry (tones) +/- 2.4 kHz from carrier |
Operational frequency
Coherent transmission at 399.968 MHz
Occasionally changes between this frequency and the maintenance one) |
149.988 |
Oscar 27 (Transit)
1987-80A
18361 |
Ionospheric modelling for US military (NIMS) |
FM telemetry (tones) +/- 2.4 kHz from carrier |
Operational frequency
Coherent transmission at 399.968 MHz
Occasionally changes between this frequency and the maintenance one)
No longer transmitting as of 2008 Jan 1 |
149.988 |
Oscar 32 (Transit)
1988-33B
19071 |
Ionospheric modelling for US military (NIMS) |
FM telemetry (tones) +/- 2.4 kHz from carrier |
Operational frequency
Coherent transmission at 399.968 MHz
Occasionally changes between this frequency and the maintenance one) |
150.000 |
Tsikada and Nadezhda |
Navigation - plus Search and Rescue monitoring |
FM time and position information - sidebands at 3 kHz, 5 kHz and 7 kHz |
Several satellites - the system is no longer operational, has been silent since 2003 November 26
Coherent transmission at 400.000 MHz |
150.012 |
ARGOS
1999-8A
25634 |
USAF space experiments |
CW - Doppler tracking beacon |
Coherent transmission at 400.032 MHz
Ceased to transmit 2003 |
150.012 |
Geosat
1985-21A
15595 |
Oceanography - wave height measurement |
CW - Doppler tracking beacon |
Detected being switched on and off over Europe, not continuously active
Coherent transmission at 400.032 MHz |
150.012 |
GFO
1998-7A
25157 |
Oceanography - wave height measurement |
CW - Doppler tracking beacon |
Geosat Follow On satellite
Coherent transmission at 400.032 MHz and also transmits at 2207.5 MHz |
150.012 |
PicoSat 9
2001-43B
26930 |
USAF Space Test Program (STEP) |
CW - Doppler tracking beacon |
Coherent transmission at 400.032 MHz
Ceased to transmit late-2004 |
150.012 |
RADCAL
1993-41A
22698 |
Radar calibration |
CW - Doppler tracking beacon |
Radar Calibration satellite
Coherent transmission at 400.032 MHz, operation is intermittent |
150.012 |
USA-147 (DMSP F-15)
1999-67A
25991 |
RADCAL secondary payload aboard US military metsat |
CW - Doppler tracking beacon |
Defense Meteorological Satellite Program
Also transmits at 2237.5 MHz and 2252.5 MHz (information contributed by the late Ivan Artner), and 400.032 MHz
Post-launch testing revealed interference with other equipment from the 150/400 MHz transmitters so they remained inactive (apart from further testing) until 2006 Aug 14 |
150.030 |
Cosmos 2361
1998-76A
25590 |
Navigation (+ comms?) |
FM time and position information - sidebands at 3 kHz, 5 kHz and 7 kHz |
Coherent transmission at 400.080 MHz |
150.300 |
Cosmos 2373
2000-58A
|
Yantar/Cometa' recoverable satellite - photographic mapping |
AM telemetry - wide bandwidth |
Coherent transmission at 400.800 MHz
Cameras and film recovered after mission running between 2000 September 29 and 2000 November 14
no longer in orbit |
150.300 |
Cosmos 2415
2005-34A
28841 |
Yantar/Cometa' recoverable satellite - wide-area photographic reconnaissance |
CW - Doppler tracking beacon |
Coherent transmission at 400.800 MHz
Cameras and film recovered after mission mission running between 2005 September 2 and 2005 October 14 - transmissions heard over the USA
no longer in orbit |
179.951 |
Jiang Bing 3A (Zi-Yuan 2)
2000-50A
26481 |
Remote Sensing |
CW carrier on centre frequency plus telemetry sidebands at +/- 20 kHz- and further carriers at +/- 40 kHz |
Coherent transmission at 479.865 MHz |
180.006 |
Fengyun 1C
1999-25A
25730 |
Meteorological imaging |
CW carrier on centre frequency plus telemetry sidebands at +/- 5 kHz- and further carriers at +/- 10 kHz |
Active transmitter until 2007 February when attacked in ground-based interceptor test
Coherent transmission at 480.017 MHz |
180.007 |
Fengyun 1D
2002-24A
27431 |
Meteorological Imaging |
CW carrier on centre frequency plus telemetry sidebands at +/- 5 kHz- and further carriers at +/- 10 kHz |
Coherent transmission at 480.017 MHz |
180.011 |
CBERS 1 (Zi-Yuan 1)
1999-57A
25940 |
Remote sensing |
CW carrier on centre frequency plus telemetry sidebands at +/- 20 kHz - and further carriers at +/- 40 kHz |
China Brasil Earth Resources Satellite
Coherent transmission at 480.025 MHz
Silent since mid 2003, the last public report being 2003 Jun 6 by Maik Hermenau of www.satellitenwelt.de |
180.013 |
CBERS 2B
2007-42A
32062 |
Remote sensing |
CW carrier on centre frequency plus telemetry sidebands at +/- 20 kHz- and further carriers at +/- 40 kHz |
China Brazil Earth Resources Satellite
Coherent transmission at 480.033 MHz |
180.014 |
CBERS 2A
2003-49A
28057 |
Remote sensing |
CW carrier on centre frequency plus telemetry sidebands at +/- 20 kHz- and further carriers at +/- 40 kHz |
China Brazil Earth Resources Satellite
Coherent transmission at 480.037 MHz
Ceased to transmit 2007 |
399.760 |
Cosmos 2341
1997-17A
24772 |
Navigation |
CW - Doppler tracking beacon |
Coherent transmission at 149.910 MHz |
399.840 |
Cosmos 2366
1999-45A
25892 |
Navigation |
CW - Doppler tracking beacon |
Coherent transmission at 149.940 MHz |
399.920 |
Cosmos 2336
1996-71A
24677 |
Navigation |
CW - Doppler tracking beacon |
Coherent transmission at 149.970 MHz |
399.944 |
Oscar 29 (Transit)
1987-80B
18362 |
Ionospheric modelling for US military (NIMS) |
Modulated CW carrier |
Maintenance frequency
Coherent transmission at 149.979 MHz (known to change between this frequency and the operational one)
No longer transmitting as of 2008 Jan 1 |
399.944 |
Oscar 31 (Transit)
1988-74B
19420 |
Ionospheric modelling for US military (NIMS) |
Modulated CW carrier |
Maintenance frequency
Coherent transmission at 149.979 MHz (known to change between this frequency and the operational one)
Sometime between 2007 Dec 21 and 2008 Feb 7, the normal transmissions at both frequencies were replaced with a highly unstable CW carrier (wandering frequency + variations in strength) |
399.968 |
Oscar 23 (Transit)
1988-33A
19070 |
Ionospheric modelling for US military (NIMS) |
Modulated CW carrier |
Operational frequency
Coherent transmission at 149.988 MHz (known to change between this frequency and the maintenance one) |
399.968 |
Oscar 25 (Transit)
1988-74A
19419 |
Ionospheric modelling for US military (NIMS) |
Modulated CW carrier |
Operational frequency
Coherent transmission at 149.988 MHz (known to change between this frequency and the maintenance one) |
399.968 |
Oscar 27 (Transit)
1987-80A
18361 |
Ionospheric modelling for US military (NIMS) |
Modulated CW carrier |
Operational frequency
Coherent transmission at 149.988 MHz (known to change between this frequency and the maintenance one)
No longer transmitting as of 2008 Feb 1 |
399.968 |
Oscar 32 (Transit)
1988-33B
19071 |
Ionospheric modelling for US military (NIMS) |
Modulated CW carrier |
Operational frequency
Coherent transmission at 149.988 MHz (known to change between this frequency and the maintenance one) |
400.000 |
Tsikada and Nadezhda |
Navigation - plus Search and Rescue monitoring |
CW - Doppler tracking beacon |
Coherent transmission at 150.000 MHz
no longer active (see 150 MHz note) |
400.032 |
ARGOS
1999-8A
25634 |
USAF space experiments |
CW - Doppler tracking beacon |
Coherent transmission at 150.012 MHz
Ceased to transmit 2003 |
400.032 |
Geosat
1985-21A
15595 |
Oceanography - wave height measurement |
CW - Doppler tracking beacon |
Coherent transmission at 150.012 MHz |
400.032 |
GFO
1998-7A
25157 |
Oceanography - wave height measurement |
CW - Doppler tracking beacon |
Geosat Follow On
Coherent transmission at 150.012 MHz and also transmits at 2207.5 MHz |
400.032 |
PicoSat 9
2001-43B
26930 |
USAF Space Test Program (STEP) |
CW - Doppler tracking beacon |
Detected being switched on and off over Europe, not continuously active
Coherent transmission at 150.012 MHz
Ceased to transmit late-2004 |
400.032 |
RADCAL
1993-41A
22698 |
Radar calibration |
CW - Doppler tracking beacon |
Radar Calibration satellite
Coherent transmission at 150.012 MHz, operation is intermittent |
400.032 |
USA-147 (DMSP F-15)
1999-67A
25991 |
RADCAL secondary payload aboard US military metsat |
CW - Doppler tracking beacon |
Defense Meteorological Satellite Program - also transmits at 2237.5 MHz (information contributed by the late Ivan Artner), and 150.012 MHz
Post-launch testing revealed interference with other equipment from the 150/400 MHz transmitters so they remained inactive (apart from further testing) until 2006 Aug 14
|
400.080 |
Cosmos 2361
1998-76A
25590 |
Navigation |
CW - Doppler tracking beacon |
Non operational but still transmitting 2000 December 13
Coherent transmission at 150.030 MHz |
400.080 |
Cosmos 2373
2000-58A
|
Navigation |
CW - Doppler tracking beacon |
Coherent transmission at 150.030 MHz |
400.550 |
Resurs O1-4
1998-43A
25394 |
Remote sensing |
CW Spread Spectrum |
Signals from Little LEO ranging between 400.318 and 400.787 MHz
Piggy-back 'store and forward' communications payload carried by Russian satellite
Transmitter not heard since 2001 February
The meteorological payload transmitted at 137.85 MHz
no longer active |
400.800 |
Cosmos 2373
2000-58A
|
'Yantar/Cometa' recoverable satellite - photographic mapping |
CW - Doppler tracking beacon |
Coherent transmission at 150.300 MHz
Cameras and film recovered after mission running between 2000 September 29 and 2000 November 14
no longer active |
400.800 |
Cosmos 2415
2005-34A
28841 |
Yantar/Cometa' recoverable satellite - wide-area photographic reconnaissance |
CW - Doppler tracking beacon |
Coherent transmission at 150.300 MHz
Cameras and film recovered after mission running between 2005 September 2 and 2005 October 14?
no longer active |
479.865 |
Jiang Bing 3A (Zi-Yuan 2)
2000-50A
26481 |
Remote sensing |
CW - Doppler tracking beacon |
Coherent transmission at at 179.951 MHz |
480.017 |
Fengyun 1D
2002-24A
27431 |
Meteorological Imaging |
CW - Doppler tracking beacon |
Coherent transmission at 180.007 MHz |
480.019 |
Fengyun 1C
1999-25A
25730 |
Remote sensing |
CW - Doppler tracking beacon |
Active transmitter until 2007 February when attacked in ground-based interceptor test
Coherent transmission at 180.007 MHz |
480.025 |
CBERS 1 (Zi-Yuan 1)
1999-57A
25940 |
Remote sensing |
CW - Doppler tracking beacon |
China Brasil Earth Resources Satellite
Coherent transmission at 180.011 MHz - silent since mid-2003 |
480.033 |
CBERS 2B
2007-42A
32063 |
Remote sensing |
CW - Doppler tracking beacon |
China Brazil Earth Resources Satellite
Coherent transmission at 180.013 MHz |
480.037 |
CBERS 2A
2003-49A
28057 |
Remote sensing |
CW - Doppler tracking beacon |
China Brazil Earth Resources Satellite
Coherent transmission at 180.014 MHz |
