[ Pobierz całość w formacie PDF ]
transmitters using similar frequencies that it is virtually impossible to filter out individual
signals1. The satellites cannot be used for the continuous monitoring of civilian radio
communications.
Alongside these satellites, the USA operates so-called quasi-geostationary SIGINT satellites
stationed in a high earth orbit (42 000 km)2. Unlike the geostationary telecommunications
satellites, these satellites have an inclination of between 3 and 10o, an apogee of between
39 000 and 42 000 km, and a perigee of between 30 000 and 33 000 km. The satellites are
thus not motionless in orbit, but move in a complex elliptical orbit, which enables them to
cover a larger area of the earth in the course of one day and to locate sources of radio
transmissions. This fact, and the other non-classified characteristics of the satellites, point to
their use for purely military purposes.
The signals received are transmitted to the receiving station by means of a strongly-focused,
24 GHz downlink.
3.3.2. Scope for the automatic analysis of intercepted communications: the use of filters
When foreign communications are intercepted, no single telephone connection is monitored
on a targeted basis. Instead, some or all of the communications transmitted via the satellite or
cable in question are tapped and filtered by computers employing keywords analysis of
every single communication would be completely impossible.
It is easy to filter communications transmitted along a given connection. Specific faxes and
e-mails can also be singled out through the use of keywords. If the system has been trained to
recognise a particular voice, communications involving that voice can be singled out3.
However, according to the information available to the rapporteur the automatic recognition
of words spoken by any voice is not yet possible. Moreover, the scope for filtering out is
restricted by other factors: the ultimate capacity of the computers, the language problem and,
above all, the limited number of analysts who can read and assess filtered messages.
1
Letter from the Minister of State in the Federal Defence Ministry, Walter Kolbow, of 14 February 2001.
2
Major Andronov, Zarubezhnoye voyennoye obozreniye, No 12, 1993, p. 37-43.
3
Information supplied privately to the rapporteur (confidential source).
DT\437638EN.doc 22/92 PE 300.153
EN
When assessing the capabilities of filter systems, consideration must also be given to the fact
that in the case of an interception system working on the basis of the vacuum-cleaner
principle those technical capabilities are spread across a range of topics. Some of the
keywords relate to military security, some to drug trafficking and other forms of international
crime, some to the trade in dual-use goods and some to compliance with embargoes. Some of
the keywords also relate to economic activities. Any move to narrow down the range of
keywords to economically interesting areas would simply run counter to the demands made
on intelligence services by governments; what is more, even the end of the Cold War was not
enough to prompt such a step1.
3.3.3. The example of the German Federal Intelligence Service
Department 2 of the German Federal Intelligence Service (FIS) obtains information through
the interception of foreign communications. This activity was the subject of a review by the
German Federal Constitutional Court. The details made public during the court proceedings2,
combined with the evidence given to the Temporary Committee on 21 November 2000 by
Mr Ernst Uhrlau, the coordinator for the secret services in the Federal Chancellor s Office,
give an insight into the scope for obtaining intelligence by intercepting satellite
communications.
On the basis of their right of access to cable communications or the availability of a greater
number of analysts, the capabilities of other intelligence services may be greater in detail
terms in given areas. In particular, the monitoring of cable traffic increases the statistical
likelihood of success, but not necessarily the number of communications which can be
analysed. In fundamental terms, in your rapporteur s view the example of the FIS
demonstrates the capabilities and strategies employed by foreign intelligence services in
[ Pobierz całość w formacie PDF ]