Measurement probe systems for co-ordinate positioning apparatus

Abstract

A measurement probe, such as a touch trigger measurement probe, is described that comprises a measurement portion for measuring an object and a data transfer portion for receiving data from and / or transmitting data to an associated unit. The measurement device also comprises an authentication module for verifying the authenticity of the associated unit. The authentication module may include a processor for running a one-way hash algorithm. Authenticity may be established using a challenge and response authentication process.

Description

[0001]This nonprovisional application claims the benefit of U.S. Provisional Application No. 60 / 996,984, filed Dec. 13, 2007.BACKGROUND OF THE INVENTION[0002]i) Field of the Invention[0003]The present invention relates to measurement devices that comprise an authentication module for verifying the authenticity of an associated unit and in particular to measurement systems that comprise a measurement probe mountable to co-ordinate positioning apparatus.[0004]ii) Description of Related Art[0005]Measurement probes for use with co-ordinate positioning apparatus, such as co-ordinate measuring machines, machine tools, inspection robots etc, are known. Examples of such measurement probes are described in US4153998, WO2004 / 57552 and WO2007 / 28964.[0006]To offer flexibility to users, measurement devices for use with co-ordinate positioning apparatus are often produced and sold as discrete modular units that are combined to establish a system that can perform the required measurement task. For...

AI Technical Summary

Benefits of technology

[0010]In this manner, the present invention ensures that any associated unit is authentic. This means that there is no requirement for a user to have to check or verify that an associated unit is fully compatible with the measurement probe system. Furthermore, it prevents third parties manufacturing associated units that can mimic the operation of an authentic device. In this manner, it is guaranteed that the measurement probe system is always used with fully compatible apparatus thereby ensuring the required levels of measurement accuracy are maintained.

[0011]Advantageously, the authentication module comprises a processor that, in use, runs an encryption algorithm. The processor is advantageously a stand-alone chip or circuit but may also be used for other processing tasks if required. Conveniently, the encryption algorithm is a one-way hash algorithm, such as the SHA-1 algorithm developed by the National Institute of Standards and Technology (NIST) of the USA. Although SHA-1 is a suitable algorithm, it should be noted that many alternative algorithms are available and could be used if required. The authentication module conveniently comprises a random data string generator which, as described in more detail below, can greatly increase the security of a challenge and response authentication process. A secure memory for storing a secret key may also be provided, the secure memory being inaccessible externally after the key has been entered.

[0012]Advantageously, the authentication module verifies the authenticity of the associated unit using a challenge and response process. The challenge and response process conveniently confirms that the associated unit holds the same secret key as the secure memory of the authentication module without disclosing the secret key.

[0014]The associated unit may be located remotely to the measurement probe system and a wireless link provided for communication therebetween. The data transfer portion thus conveniently comprises a transmitter and / or a receiver for providing a wireless communications link with an associated unit. The data transfer portion may thus provide an optical, RF or other suitable type of wireless communications link as required. Alternatively, the data transfer portion may comprise at least one electrical contact for providing a conductive electrical connection with an associated unit. In such an example, the associated unit may be brought into electrical contact with the electrical contact(s) of the measurement probe system as and when required. If the data transfer portion and any associated electrical contacts are provided on the measurement probe, a cover or lid may be provided to protect such contacts and / or any attached associated unit from physical damage.

[0016]As well as, or instead of, receiving measurement data the associated unit may comprise data that can be transferred to the measurement probe system. For example, the associated unit may comprise an activation button, smart card, control fob or similar that includes a store of trigger credits or contains updates to the software that is being run by the measurement probe system. In other words, data may be stored by the associated unit. The associated unit may thus be advantageously arranged to transmit information relating to operation of the measurement probe system. Conveniently, any such transmitted information is only acted upon by the measurement probe system if the authentication module has verified that the associated unit is authentic. In this manner, it can be assured that any data that is uploaded to, and acted upon, by the measurement probe system is authentic.

Problems solved by technology

Furthermore, it prevents third parties manufacturing associated units that can mimic the operation of an authentic device.