Klaus Briess

BIRD detection and analysis of high-temperature events: first results

The primary mission objective of a new small Bi-spectral InfraRed Detection (BIRD) satellite, which was put in a 570 km circular sun-synchronous orbit on 22 October 2001, is detection and quantitative analysis of high-temperature events (HTE) like fires and volcanoes. A unique feature of the BIRD mid- and thermal infrared channels is a real-time adjustment of their integration time that allows a HTE observation without sensor saturation, preserving a good radiometric resolution of 0.1-0.2 K for pixels at normal temperatures. This makes it possible: (a) to improve false alarm rejection capability and (b) to estimate HTE temperature, area and radiative energy release. Due to a higher spatial resolution, BIRD can detect an order of magnitude smaller HTE than AVHRR and MODIS. The smallest verified fire that was detected in the BIRD data had an area of ~12 m2. The first BIRD HTE detection and analysis results are presented including bush fires in Australia, forest fires in Russia, coal seam fires in China, and a time-varying thermal activity at Etna.

Detection, monitoring, and quantitative analysis of wildfires with the BIRD satellite

Increasing concern about environment and interest to avoid losses led to growing demands on space borne fire detection, monitoring and quantitative parameter estimation of wildfires. The global change research community intends to quantify the amount of gaseous and particulate matter emitted from vegetation fires, peat fires and coal seam fires. The DLR Institute of Space Sensor Technology and Planetary Exploration (Berlin-Adlershof) developed a small satellite called BIRD (Bi-spectral Infrared Detection) which carries a sensor package specially designed for fire detection. BIRD was launched as a piggy-back satellite on October 22, 2001 with ISRO’s Polar Satellite Launch Vehicle (PSLV). It is circling the Earth on a polar and sun-synchronous orbit at an altitude of 572 km and it is providing unique data for detailed analysis of high temperature events on Earth surface. The BIRD sensor package is dedicated for high resolution and reliable fire recognition. Active fire analysis is possible in the sub-pixel domain. The leading channel for fire detection and monitoring is the MIR channel at 3.8 μm. The rejection of false alarms is based on procedures using MIR/NIR (Middle Infra Red/Near Infra Red) and MIR/TIR (Middle Infra Red/Thermal Infra Red) radiance ratio thresholds. Unique results of BIRD wildfire detection and analysis over fire prone regions in Australia and Asia will be presented. BIRD successfully demonstrates innovative fire recognition technology for small satellites which permit to retrieve quantitative characteristics of active burning wildfires, such as the equivalent fire temperature, fire area, radiative energy release, fire front length and fire front strength.

Sensor system for fire detection on-board the small satellite BIRD

With the successful launch of BIRD satellite in October 2001, new possibilities of the observation of hot events like forest fires, volcanic eruptions a.o. from space are opened. The BIRD (Bi-spectral Infrared Detection) is the first satellite which is equipped with space instrumentation dedicated to recognize high temperature events. Current remote sensing systems have the disadvantage that they were not designed for the observation of hot events. Starting with the FIRES Phase A Study, the principle requirements and ideas for a fire recognition system were defined. With the German BIRD demonstrator mission, a feasible approach of these ideas has been realized and work now in space. This mission shall answer technological and scientific questions related to the operation of a compact bi-spectral infrared push-broom sensor and related to the detection and investigation of fires from space. The payload of BIRD is a multi-sensor system designed to fulfil the scientific requirements under the constraints of a micro satellite. The paper describes the basic ideas for fire detection and the estimation of fire temperature, fire size, and energy release in the sub-pixel domain and describes the technical solution for the infrared sensor system on board of BIRD.

Space-Borne Autonomous On-Board Recognition of High Temperature Events

Satellite fire detection and monitoring observations are currently in an experimental or preoperational phase and directed to the development and testing of fire detection and analysis algorithms.

The BIRD payload platform

For hot spot events as forest fires, volcanic activity or burning oil spills and coal seams a dedicate dspace instrumentation does not exist. With its successful launch end of October 2001 with the Indian Polar Satellite Launch Vehicle the German Aerospace Center starts closing this gap with the micro-satellite mission BIRD. As space segment serves a three-axis stabilized satellite of 92 kg including a contingent of over 30% for the scientific instruments. The main payload of the BIRD micro-satellite is the newly developed Hot Spot Recognition System. Its a dual-channel instrument for middle and thermal IR imagery based on cooled MCT line detectors. The miniaturization by integrated detector/cooler assemblies provides a highly efficient design. A complement for the hot spot detection is the wide-angle stereo-scanner WAOSS-B. It is a hardware re-use dedicated to vegetation and cloud assessment in the visible spectral range. Besides the main objective of hot spot detection the mission has to answer several technological questions of the operation of cooled detectors in space, special aspects of their adaptation to the satellite platform as well as their calibration.

Objectives and results of the BIRD mission

The DLR small satellite BIRD (Bi- spectral Infrared Detection) is successfully operating in space since October 2001. The main payload is dedicated to the observation of high temperature events and consists mainly of a Bi-Spectral Infrared Push Broom Scanner (3.4-4.2μm and 8.5-9.3μm), a Push Broom Imager for the Visible and Near Infrared and a neural network classification signal processor. The BIRD mission answers topical technological and scientific questions related to the operation of a compact infra-red push-broom sensor on board of a micro satellite. A powerful Payload Data Handling System (PDH) is responsible for all payload real time operation, control and on-board science data handling. The IR cameras are equipped with an advanced real time data processing allowing an autonomously adaptation of the dynamic range to different scenarios. The BIRD mission control, the data reception and the data processing is conducted by the DLR ground stations in Weilheim and Neustrelitz (Germany) and is experimentally performed by a low cost ground station implemented at DLR Berlin-Adlershof. The BIRD on ground data processing chain delivers radiometric and geometric corrected data products, which will be also described in this paper. The BIRD mission is an exemplary demonstrator for small satellite projects dedicated to the hazard detection and monitoring.

The Role of Small Satellite Missions in Global Change Studies

There is an increasing need for Earth Observation (EO) missions to meet the information requirements in connection with Global Change Studies. Small and cost-effective missions are powerful tools to flexibly react on information requirements with space borne solutions. Small satellite missions can be conducted relatively quickly and inexpensively and provide increased opportunity for access to space. The spacecraft bus and instruments can be based either on optimised off-the-shelf systems, with little or no requirements for new technology, or on new high-technology systems. Thus a new class of advanced small satellites, including autonomously operating “intelligent” satellites may be created, opening new fields of application for scientific purposes as well as operational, public and commercial services. Further milestones in the small satellite Earth observation mission developments are the availability and improvement of small launchers, the development of small ground station networks connected with rapid and cost-effective data distribution methods, and cost-effective management and quality assurance procedures. Advantages of small satellite missions, complementing the large complex missions are: more frequent mission opportunities and therefore faster return of science and application data; larger variety of missions and therefore also greater diversification of potential users; more rapid expansion of the technical and/or scientific knowledge base; and greater involvement of local and small industry. The paper deals with general trends in the field of small satellite missions for Earth observation. Special attention is given to the potential of spatial, spectral, and temporal resolution of small satellite based systems. Examples show that constellations give the unique for small satellites possibility to provide good daily coverage of the globe or/and allow to observe dynamic phenomena.

Design and Implementation of a Remote, Server-Client- Based Telemetry Retrieval and Monitoring System

Telemetry retrieval and monitoring is one of the basic functionalities of every satellite Electrical Ground Support Equipment, EGSE. There are hence a vast number of different tools and systems available for this purpose. Most of these systems have been, however, developed in the context of individual satellite projects or in some cases even a single payload. A limited number of multi-mission and more general purposed telemetry retrieval systems exist presently as an integrated part of major commercial EGSE systems, which are used at the professional satellite control centres. The use of these systems in a new satellite projects requires respectively certain adaptation of the system or the satellite hardware/software. Another lacking functionality of many telemetry retrieval systems is their local accessibility, where there is no or limited remote interface to the system through the internet. In this paper a low-cost, modular and flexible telemetry retrieval system with a server-client based architecture is presented. It allows the remote clients to login to the system through the internet, using conventional web-browsers and monitor the satellite telemetry data in real-time during a satellite pass. It also offers functionalities for off-line data analysing, graphical visualising and telemetry database administration through the web interface. The system has been developed at the German Aerospace Centre, DLR and the TU-Berlin and is being used for retrieving telemetry data of the DLR satellite BIRD at TUBerlin. The ESA Young Engineers Satellite, YES2 is another potential user of the system. The complete platform independency of the system and its pure object oriented and modular software architecture makes it a highly flexible and reusable telemetry retrieval and monitoring system. The objective of an easy adaptation and cross-mission reusability of the system has been the major design deriver and has lead to the development of a dedicated Application Programming Interface, API. Satellite engineers can use the introduced API to develop new modules and to extend the existing ones, in order to adapt the system to the requirements of a new satellite project.

An autonomous information generation and distribution system for the next generation of small satellites: examples of the BIRD mission experiments

The general trend in remote sensing is on one hand to increase the number of spectral bands and the geometric resolution of the imaging sensors which leads to higher data rates and data volumes. On the other hand the user is often only interested in special information of the received sensor data and not in the whole data mass. Concerning these two tendencies a main part of the signal pre-processing can already be done for special users and tasks on-board a satellite. For the BIRD (Bispectral InfraRed Detection) mission a new approach of an on-board data processing is made. The main goal of the BIRD mission is the fire recognition and the detection of hot spots. This paper describes the technical solution and the first results, of an on-board image data processing system based on the sensor system on two new IR-Sensors and the stereo line scanner WAOSS (Wide-Angle-Optoelectronic-Scanner). The aim of this data processing system is to reduce the data stream from the satellite due to generations of thematic maps. This reduction will be made by a multispectral classification. For this classification a special hardware based on the neural network processor NI1000 was designed. This hardware is integrated in the payload data handling system of the satellite.

Onboard autonomy and fault protection concept of the BIRD satellite

BIRD (Bi-Spectral Infra-Red Detection) has been demonstrating new technologies since its launch on 22. October, 2001 with the PSLV-C3 from Shar/India successfully into a sun-synchronous low Earth orbit at 560 km. Besides the successful in-orbit test of the detection and evaluation of vegetation fires with micro satellites, BIRD has also been demonstrating a number of advanced spacecraft bus technologies, especially in the field of satellite autonomy and fault detection and protection. A number of ingenious features make it possible to operate the 92 kg satellite in a comfortable and safely way. Special features include the autonomous management of onboard computer failures, surveillance and response to critical parameters limit exceeding, system attitude anomalies. A robust redundancy philosophy and optimised ground-spacecraft interaction concept has contributed to the success of the BIRD mission, which was designed to operate for one year and has completed now its second year of operation. The paper describes the related new technologies and the results from the experience with BIRD.