Controlling an underground object
In order to control the sonde of an underground object, such as an underground boring tool, a predetermined sequence of rotation steps is applied to the object and that sequence is detected. The detection of the appropriate sequence causes the sonde to change its function, for example by changing the carrier frequency of the signal transmitted by the sonde on to change the data output sequence or transfer rate, or to change output power. While it is possible to use a single rotation step, the use of more than one step, with each step to be carried out within a predetermined time, reduces the risk of error.
1. A method of operating an underground or inaccessible object, said object including a sonde arranged to emit signals having a plurality of non-orientation-dependent characteristics, said method comprising the steps of:
applying a predetermined rotation sequence involving at least one rotation step to said object;
detecting, said rotation sequence;
wherein said detection of said rotation sequence causes said sonde to change from the emission of a hint signal having a first non-orientation-dependent characteristic to the emission of a second signal having a second nonorientation-dependent characteristic.
2. A method according to claim 1 wherein said first non-orientation-dependent characteristic and said second non-orientation-dependent characteristic of said signal are a first carrier frequency and a second carrier frequency respectively.
3. A method according to claim 1 wherein said first non-orientation-dependent characteristic and said second non-orientation-dependent characteristic of said signal are a first data output sequence and a second data output sequence respectively.
4. A method according to claim 1 wherein said first non-orientation-dependent characteristic and said second non-orientation-dependent characteristic of said signal are a first data transfer rate and a second data transfer rate respectively.
5. A method according to claim 1 wherein said first non-orientation-dependent characteristic and said second non-orientation-dependent characteristic of said signal are a first output power and a second output power respectively.
6. A method according to claim 1 wherein said rotation sequence comprises a plurality of steps is completed within a predetermined time limit.
7. Apparatus for operating an underground or inaccessible object, said apparatus including:
a sonde for emitting a plurality of signals having predetermined non-orientation-dependent characteristics of the underground or inaccessible object;
rotation means for applying a predetermined rotation sequence involving at least one rotation step to said object;
detection means for detecting said predetermined rotation sequence; and
response means activated by said detection of said predetermined rotation sequence for causing said sonde to change from the emission of a first signal having a first non-orientation-dependent characteristic to the emission of a second signal being a second non-orientation dependent characteristic.
8. Apparatus according to claim 7 wherein said object is an underground boring tool and said detection means is a roll sensor.
9. A method of operating an underground or inaccessible object including a sonde, said object being connected to an operator triggered drive means, said method comprising the steps of:
signaling from said drive means to said sonde, said
signaling including the operator triggering said
operator triggered drive means to apply a predetermined rotational sequence involving at least one rotation step to said object;
detecting said rotation sequence, wherein said detection of said rotation sequence causes said sonde to change from a first signal modulation to a second signal modulation.
10. A method according claim 9 wherein said rotation sequence-comprises a plurality of rotation steps.
11. A method according to claim 10 wherein each rotation of said plurality of steps is completed within a predetermined time limit.