DE102005016209A1 - Alarm signal generating and transmitting method for e.g. deep flying satellite, involves generating alarm signal, on detecting system failure, using error message and navigation satellites signals, and transmitting alarm signal to station - Google Patents

Abstract

The method involves instantly generating an alarm signal, when a serious system failure e.g. failure of sensor, on board a satellite (9) is detected by a communication unit (1) provided on the satellite. The alarm signal is generated using error message of a computer and using signals from navigation satellites (7, 8). The alarm signal is transmitted to a receiving station (11) by a Galileo satellite (6), where the receiving station receives the alarm signal. The alarm signal is forwarded to a satellite control center that is responsible for operation of the satellite. An independent claim is also included for a device for generation and transmission of an alarm signal on board of a satellite.

Description

The The invention relates to a method for generating an emergency signal on board a satellite and its transmission.

The Communication of satellites with a satellite control center over transmitting payload and satellite data from the satellite to one Ground station, which is part of a specific ground station segment represents. For low-flying satellites the duration between two ground station contacts usually several hours. So far you can Therefore, serious system failure aboard a satellite, such as the failure payload, sensors and actuators, from the control center first be detected when the satellite is back in contact with the ground station a specific ground station segment occurs.

Of the Disadvantage of the existing operating concept for low-flying satellites is that while in case of serious system errors on board the satellite usually a safe-position mode is activated, the maintenance of minimal functionality aboard the satellite ensure, but no timely message of the error takes place to the satellite operator. This is a timely preparation not possible for suitable rescue and countermeasures.

Of the Invention is based on the object under the restrictions of an existing ground station segment, a timely notification of heavy System errors on board a satellite to the satellite operator to convey. According to the invention This object is achieved in a method according to the preamble of Claim 1 solved by the features in its characterizing part. advantageous Further developments are the subject matter of claim 1 directly or indirectly related Claims.

According to the invention will aboard a satellite upon detection of serious system errors a communication unit generates an emergency signal. The distress signal will over one equipped with a suitable communication unit second satellite forwarded to a receiving station for distress signals. After all the emergency signal is transmitted from the emergency signal receiving station to one for satellite operation competent Control Center transmitted.

According to one advantageous development of the method according to the invention is the emergency signal Board the satellite bordautonom and in real time using a Error message of the on-board computer and optionally using the signals of a global navigation satellite system.

According to one advantageous embodiment of the method according to the invention can be used as a satellite for transmission the emergency signal equipped with a Search and Rescue (SAR) functionality Be used satellite of a global navigation satellite system. For global Satellite Navigation Systems (GNSS) are the American Global Positioning System (GPS), the Russian counterpart GLONASS as well as that in planning located European Galileo system. This is a transmission the emergency signal in real time to a ground station for distress signals guaranteed.

at the method according to the invention can Advantageously, the use of existing SAR systems, the so far exclusively for terrestrial, maritime or airborne users be used, also for Space-based Applications are used. An example of a SAR system is COSPAS-SARSAT, its space segment of low-flying satellites (LEOSAR) and geostationary satellites (GEOSAR) exists. This should be future be extended to GNSS (MEOSAR).

According to one advantageous development of the invention can by means of a satellite navigation receiver the Relative speeds between a satellite and the satellites of the GNSS. Since satellites of the GNSS, in particular Galileo, future with specially for SAR applications designed telecommunications units can be, by means of a calculated relative speed Doppler compensation of the distress signals done, allowing a robust reception the distress signal emitted by the satellite at one of the GNSS satellites possible is.

following The invention will be explained with reference to drawings in detail. It demonstrate:

1 in a block diagram functional units and between them extending signal data paths and

2 likewise in a block diagram an embodiment of a satellite on-board computer downstream communication unit for generating an emergency signal.

In the 1 The device shown has five functional blocks 1 to 5 on board on a satellite 9 are located. This includes the function block 1 a communication unit for generating a digital emergency message. The functional block 2 includes a satellite on-board computer that works with the function blocks 1 and 3 to 5 connected is. The functional blocks 3 and 4 represent typical subsystems of the satellite, such as a position control system, a thermal system, a communication system, an electrical system or a propulsion system for satellites.

In the event of failure of a critical component of one of the subsystems or any other serious malfunction, this will be done by the satellite on-board computer in the functional block 2 registered, which then autonomously and in real time an emergency message to the communication unit (function block 1 ) for emergency signals. The function block 5 is optional and is used for Doppler compensation; the function block 5 includes a satellite navigation receiver and an antenna for receiving signals of a global navigation satellite system, of which for purposes of illustration two navigation satellites 7 and 8th are shown.

The satellite equipped with a suitable communication unit 6 For example, a Galileo satellite receives it from the satellite 9 emitted emergency signal and directs the distress signal to a arranged on the ground receiving station 11 for emergency signals on. The receiving station 11 Forwards the emergency call to a satellite control center 10 Next, which is responsible for the operation of the satellite in an emergency situation.

The in 2 detailed functional block 1 has five function blocks 12 to 16 on. If an emergency message is issued by the on-board computer 2 of the satellite 9 , so first an emergency message is generated autonomously and in real time (function block 12 ), which in addition to an identification number that identifies the satellite, may contain other parameters, such as the type of fault that has occurred or the time of the fault. This message is sent by means of a modulator 13 in a known manner, for example by means of frequency modulation, modulated onto a carrier frequency transmitted via a transmitting unit 14 and an antenna 15 transmitted with hemispherical or omnidirectional radiation.

In the event that the bandwidth of the communication system in the satellite 6 the high relative speeds between the satellite 9 and the satellite 6 not supported, can, provided the satellites 6 . 7 , and 8th belong to the same system, an on-board Doppler compensation be performed. For this purpose, the relative speed information of the system using the functional unit 5 via the on-board computer 2 of the satellite 9 to the communication unit 1 transfer. Through the Doppler compensation unit 16 For example, based on the knowledge of corresponding relative speeds, the modulation of the transmitted signal can be changed such that the reception of the emergency signal at the satellite 6 without Doppler shift is possible. This is a robust reception of the emergency signal in the receiver of the satellite 6 ensured.

The use of existing and future SAR communication payloads can be used with the in 2 represented communication unit 1 be achieved. For example, existing payloads of the COSPAS-SARSAT system on low-flying satellites (LEOSAR) and geostationary satellites (GEOSAR) will in future be complemented by GNSS SAR payloads (MEOSAR). The communication unit can be used to use the COSPAS-SARSAT system 1 for distress signals so that the signal is transmitted at 406 MHz, whereby a message with a length of 112 bits or 144 bits can be transmitted in the frequency modulation method.

One An essential advantage of the invention is based on the fact that as an SAR payload for forwarding the distress signal a so equipped Satellite of a GNSS can be used. As for deep-flying satellites at least four satellites of a GNSS are visible at any time, for example four Galileo satellites, is a receipt of distress signal at least one of the GNSS satellites. This ensures the use the satellites of a GNSS a permanent global communication possibility for SAR and allows so the receipt of an emergency message at the control center in real time.

• • Vorbereitung des Bodenbetriebspersonals auf eine Notsituation für den nächsten zu erwartenden Kontakt mit der Bodenstation;
• • kurzfristige Anmietung zusätzlicher Bodenstationen zur Verkürzung der durch die geographische Verteilung der Bodenstationen gegebenen Kommunikationslücken;
• • Reduzieren des Bodenpersonals im Routinebetrieb aufgrund permanenter Kenntnis über die Nominalität der Mission sowie
• • Reduzieren der Versicherungsprämien im Routinebetrieb der Mission durch verbesserte Kenntnis des Missionszu standes und der gegebenenfalls zu treffenden Maßnahmen.

Significant advantages of the inventive method for on-board autonomous generation and forwarding of an emergency signal in real time are listed below:

• • preparing ground operations personnel for an emergency situation for the next expected contact with the ground station;
• • short-term leasing of additional ground stations to reduce the communication gaps caused by the geographical distribution of ground stations;
• • Reduction of ground personnel in routine operations due to permanent knowledge of the mission's nominality as well as
• • reduce mission-related insurance premiums by better understanding the mission status and any action that may be taken.

Further advantages of the method according to the invention are the market potential in the development of new SAR subsystems for satellites in the space industry, the expansion of the SAR functionality of existing space systems applications and the implementation of an emergency call process chain for satellite mission operators.

1

communication unit for emergency signals

2

Satellite-board computer

3.4

Satellite subsystem (e.g., location control)

5

Satellite navigation receiver

6

communications satellite

7.8

navigation satellite

9

satellite

10

satellite Control of the satellite with emergency i

situation

11

receiving station for emergency signals

12

unit for generating a digital emergency message

13

modulator

14

transmission unit

15

transmitting antenna

16

doubler compensation unit

Claims (6)

Method for generating an emergency signal on board a satellite and its transmission, characterized in that upon detection of a serious system error on board a satellite ( 9 ) from one on the satellite ( 9 ) communication unit ( 1 ) immediately generates an emergency signal, the emergency signal promptly via a equipped with a suitable communication unit satellites ( 6 ) to a receiving station ( 11 ), which is provided for the reception of emergency signals, and the distress signal from the receiving station ( 11 ) to a satellite control center ( 10 ) is forwarded. Method according to Claim 1, characterized in that the emergency signal on board the satellite ( 9 ) bordautonom and in real time using an error message of the aboard the satellite ( 9 ) or optionally generated using the signals of a global satellite navigation system. Method according to claim 1, characterized in that that as a communication unit for Emergency signals on low-flying satellites (LEOSAR), geostationary satellites (GEO-SAR) or satellites a Global Navigation Satellite System (MEOSAR), such as the Global Positioning Systems (GPS) and / or Galileo existing communication systems be used. Method according to claim 1, characterized in that existing Search and Rescue Systems (SAR), which are responsible for terrestrial, maritime or aviation-based Applications are used on space SAR applications be extended. Method according to one of the preceding claims, characterized in that a Doppler compensation of an emitted emergency signal due to relative velocities calculated by means of a satellite navigation receiver between the satellite affected by a disturbance ( 9 ) and the satellite equipped with a communication unit ( 6 ) of the satellite navigation system. Device for generating an emergency signal on board a satellite and its forwarding, characterized by an aboard the satellite ( 9 ) provided communication unit ( 1 ), which has a unit ( 12 ) for generating a digital emergency message in the event of a serious system error, a modulator ( 13 ), by means of which the emergency message is modulated onto a carrier frequency and a transmitting unit ( 14 ) with a downstream antenna ( 15 ) with hemispherical or omnidirectional radiation over which the carrier frequency modulated emergency message to a satellite ( 6 ) is transmitted with a suitable communication device.