The invention claimed is:1. A radio communication equipment installed on a vehicle, comprising:a radio communicator configured to perform radio communication with a network; anda controller configured to perform location registration and emergency call origination to a public safety answering point (PSAP) as an emergency call process via the network, whereinthe controller is configured to,determine that the emergency call origination has failed;perform any one of termination of the emergency call process or continuation of the emergency call process, according to a failure cause value notified via the network, when at least one of the location registration and the emergency call origination is failed when the emergency call process is performed via the network in occurrence of an emergency situation;receive, as the failure cause value of the emergency call origination, a first failure cause value indicating that a telephone number of the radio communication equipment is not notified to the PSAP even when the location registration is successful;terminate the emergency call process in response to receiving the first failure cause value;receive, as the failure cause value of the emergency call origination, a second failure cause value indicating that the telephone number of the radio communication equipment is notified to the PSAP when the location registration is successful; andretry the emergency call in response to receiving the second failure cause value.2. The radio communication equipment according to claim 1, whereinwhen the location registration is failed, the controller is configured to terminate the emergency call process when the failure cause value is a value indicating a case of expectation that no location registration is performable, andwhen the location registration is failed, the controller is configured to try the location registration when the failure cause value is a value indicating a case of expectation that location registration is performable.3. The radio communication equipment according to claim 1, whereinwhen the emergency call origination is failed, the controller is configured to terminate the emergency call process when the failure cause value is a value indicating a case of expectation that no emergency call origination is performable.4. A vehicle on which the radio communication equipment according to claim 1 is installed.5. The radio communication equipment according to claim 1, wherein the controller is configured to,start a timer in response to receiving the second failure cause value;continue the emergency call process during running the timer; andterminate the emergency call process in response to the timer expired.6. A control method for a radio communication equipment installed on a vehicle, the radio communication equipment comprising:a radio communicator configured to perform radio communication with a network, anda controller configured to perform location registration and emergency call origination to a public safety answering point (PSAP) as an emergency call process via the network,the control method for the radio communication equipment, comprisingdetermining that the emergency call origination has failed;performing any one of termination of the emergency call process or continuation of the emergency call process, according to a failure cause value notified via the network, when at least one of the location registration and the emergency call origination is failed when the emergency call process is performed via the network in occurrence of an emergency situation;receiving, as the failure cause value of the emergency call origination, a first failure cause value indicating that a telephone number of the radio communication equipment is not notified to the PSAP even when the location registration is successful;terminating the emergency call process in response to receiving the first failure cause value;receiving, as the failure cause value of the emergency call origination, a second failure cause value indicating that the telephone number of the radio communication equipment is notified to the PSAP when the location registration is successful; andretrying the emergency call in response to receiving the second failure cause value.